# Viessmann Vitodens 100 w/RTV-52 tank



## futz

It's been a while since I posted one of these. This one was nice to do - roomy and fairly simple. It's a Viessmann Vitodens 100 doing four zones of radiant, with a Bradford White RTV-52 tank. I wired and vented it, but gas was done by others.

Before you start nagging, the floor is dropped over an inch. The entire floor is a pan.









This pic is a stitch of three pics so there's some fairly severe distortion. Some stuff looks crooked, but it actually isn't.




































That coil of LVT on the left is for the outdoor sensor. It's not connected yet. Once we don't need temporary heat anymore I'll connect it up.


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## user2090

How long does it take to plumb, something like that in? What benefit is there to using a unit like that? I can see space savings, but was wondering what else. 

Looks good to me, right up my alley, once I get my foot in the door on one or two. I cannot say that I have ever seen anything like that in my neck of the woods. Maybe one of the factories or industrial facility. Seems like most people get talked into the forced air equipment.


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## breid1903

heell indie we live indiana. all the rich folks live in bc. lol. breid............:rockon:


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## futz

Indie said:


> How long does it take to plumb, something like that in?


For just that mechanical room (there's a lot more work in the slabs and walls/ceilings that you don't see here) there's probably a not-too-long day of pre-fab in the shop. Then roughly 32ish hours or more (includes a few trips to the supplier) to pipe/wire/purge/fire that room, including waterpipes.



> What benefit is there to using a unit like that? I can see space savings, but was wondering what else.


High efficiency - AFUE 95% or so. Condensing boilers like that are a perfect match for in-slab radiant heating. It's real quiet. Nice fast (~ 15 minute) DHW recovery too, though you get that with a conventional low efficiency boiler too.



> Seems like most people get talked into the forced air equipment.


Forced air is much cheaper. When the economy is bad here I do lots fewer hydronic jobs. Last five or six years I've done a lot - business has been hot.


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## Redwood

Indie said:


> What benefit is there to using a unit like that?


Comfort Indie... Comfort....

Much much nicer than burnt air....:thumbup:


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## user2090

Redwood said:


> Comfort Indie... Comfort....
> 
> Much much nicer than burnt air....:thumbup:


That is not very specific there Red. I mean, why a unit like that compared to something a bit less complicated. I presume that is a condensing unit.


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## user2090

Sorry Futz, I missed your reply. Thanks for the info. Why that brand, if you don't mind?


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## hydronicsbob

nice job. I've got to ask. What is that "valve" on the pipe that is by the water heater, in front, and it goes vertical and when it 90's into horizontal (back towards the wall) there is something right there with a black handle?


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## futz

Indie said:


> Why that brand, if you don't mind?


Why not? It's what my favorite supplier carries. I like Viessmann products. They're well designed and built and priced competitively. They're easy to service. Their local reps are very helpful if I have problems/questions. I have used other brands over the years though, so it's not like I'm stuck on only Viessmann.


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## futz

hydronicsbob said:


> nice job. I've got to ask. What is that "valve" on the pipe that is by the water heater, in front, and it goes vertical and when it 90's into horizontal (back towards the wall) there is something right there with a black handle?


There's no black handled valves on that job, to my knowledge. Seems to me they're all yellow handled Kitz ball valves. Are you perhaps referring to the vacuum breaker on the HWT supply?


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## hydronicsbob

thats it a vacuum breaker. Thanks, I couldn't quite make that out.


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## Scott K

I see a few problems right now with the system as it is installed.

1) On the radiant system (pump, zone valves, etc.), I do not see a differential pressure bypass. This means, that right now, sinice this pump is a fixed speed pump when only one zone opens it will be trying to ram all it's flow through one zone valve. This will create flow noise and possibly premature erosion on the heating main, depending on what speed it is set at. For the record - a Grundfos Alpha is actually about the same price as a 15-58 and a piped in differential pressure bypass, however the Alpha uses half the power (it's a no brainer me thinks). It is a against the heating code too (TECA manaul - clause 3.18). I like the fact there is a high limit (aquastat) on the radiant distribution however. 

2) I can't for the life of me understand why there is all this effort to pipe around the control/relay/electical box in the top right (i.e. zone valves/associated piping). If not a well recommended practice within the industry, it should be common sense that if there is the oppurtunity to, keep all electrical/control hardware/accessories above water, if at all possible. In this instance, it was very possible. 

3) I can't for the life of me understand why the need for all the extra air seperation/removal devices. There is an air seperator, 2 auto air vents, plus a low loss header in the Mechanical room alone. I could do all ALL of the above with primary secondary piping, a good air seperator and one tee with a purge point (hose bib) put just upstream of the shut of valve on the return of the secondary piping. In fact the past 2 systems I have installed, after a careful reasonable purge, had all the air removed within 20 minutes by the air seperator after an initial purge using the fill valve and a hose to the drain to get the most of the air out. And I have done it on dozens of systems with no issues. That, and careful hydronic design to work with the pumps and their velocity to help push air along at 2-4 feet per second, ensures once it's out, it's out. 

4) There is hard piped in black iron steel up to the regulators, and then a flex connector? Why not just finish the job in steel with some nipples/fittings? (Sorry, I am not a fan of flex connectors on gas if I don't need them and this is one situation where it isn't needed - perphaps my personal preference here however). 

5) I realize it may be a common practice for some to zap strap wiring to piping, however let me assure everyone that zap straps DO dry out and eventually become brittle enough over time to fail. I have seen it happen, and it's inevitable when the Vitodens 100 ramps up to 172 degrees to heat the indirect. 

6) There is no drain down at the bottom of the indirect coil. 

7) I like the fact that the expansion tank is hanging - that's the best position for an expansion tank. However there is no other support seen -it's not a bad idea to put some all around or some other means. Also, from a servicing stand point there is no way to isolate/check/drain down the expansion tank as it currently stands. Usually a shut off valve with a drain down between the valve and tank allows the annual service tech to check the air pressure of the tank, as well as makes for a much quicker re & re when the expansion tank does fail.


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## futz

Scott K said:


> 1) On the radiant system (pump, zone valves, etc.), I do not see a differential pressure bypass. This means, that right now, sinice this pump is a fixed speed pump when only one zone opens it will be trying to ram all it's flow through one zone valve. This will create flow noise and possibly premature erosion on the heating main, depending on what speed it is set at.


You talk like you've never done one - maybe only read about them in books. :laughing: Flow noise and erosion? In a radiant system? It just isn't going to happen. These things are dead silent except for the hum of the pumps and the boiler burner and fan noise, even with the pump on highest speed. And I've serviced many, many very old systems built without differential pressure bypasses and have never seen any evidence of erosion. Maybe it happens on some kind of giant industrial heating systems? I don't know. It just doesn't happen in residential heating.

That pump might be _trying_ to ram all its flow through one zone valve, but that doesn't mean it's actually going to go. :laughing: As much will go as can go through that tiny valve port and then the pump will just sit there and push (like a partial deadhead). Works fine - doesn't hurt a thing - and there's no flow noise.



> For the record - a Grundfos Alpha is actually about the same price as a 15-58 and a piped in differential pressure bypass, however the Alpha uses half the power (it's a no brainer me thinks).


I'll look into those. I've seen the flyers and magazine ads, but I tend to stick to the tried and true ways until I'm sure the new products are proven. Sounds like a decent pump, on paper. 



> It is a against the heating code too (TECA manaul - clause 3.18).


Then Sherets' heating guys are giving me illegal boiler layouts. I very much doubt they are.



> I like the fact there is a high limit (aquastat) on the radiant distribution however.


They're a pretty good last line of defense for the loops in case several other things all go wrong at once.



> 2) I can't for the life of me understand why there is all this effort to pipe around the control/relay/electical box in the top right (i.e. zone valves/associated piping). If not a well recommended practice within the industry, it should be common sense that if there is the oppurtunity to, keep all electrical/control hardware/accessories above water, if at all possible. In this instance, it was very possible.


The electrical box went on last, in the only bare piece of wall left. The only "water" above it is straight pieces of pipe, which will never leak. I could understand your concern if I put the box below the zone valves or other potential leakable parts, but it's fine where it is. I'm not concerned with its location at all.



> 3) I can't for the life of me understand why the need for all the extra air seperation/removal devices. There is an air seperator, 2 auto air vents, plus a low loss header in the Mechanical room alone. I could do all ALL of the above with primary secondary piping, a good air seperator and one tee with a purge point (hose bib) put just upstream of the shut of valve on the return of the secondary piping. In fact the past 2 systems I have installed, after a careful reasonable purge, had all the air removed within 20 minutes by the air seperator after an initial purge using the fill valve and a hose to the drain to get the most of the air out. And I have done it on dozens of systems with no issues. That, and careful hydronic design to work with the pumps and their velocity to help push air along at 2-4 feet per second, ensures once it's out, it's out.


The air separator and low-loss header are on the layout. Yes, it's a bit redundant, but the inspector will follow that thing blindly and want to see all the parts that are on the diagram.

The vent above the DHW pump intake is just to ensure that any potential air bubble that could get stuck in that elbow and/or get pulled into the pump gets removed easily. If it hits the pump then that's all she wrote - pumps can't pump air - I'd have to loosen the upper flange to get that air out. How do I know? I used to leave that vent out and had to do that flange loosening thing to get the DHW coil purged. I learned my lesson. The extra vent is necessary.

The one on the zone valve manifold is at the high point of that piece of piping. Once again, if it isn't there then any air that gets up there is very likely to just stay there and be noisy and difficult to dislodge. I want any bit of air that collects there out of the system before it gets into my loops, as there are no AAVs on the loop manifolds (far too risky to have those pissy frickin things inside the house). As far as I'm concerned it's necessary and I will always put one there.



> 4) There is hard piped in black iron steel up to the regulators, and then a flex connector? Why not just finish the job in steel with some nipples/fittings? (Sorry, I am not a fan of flex connectors on gas if I don't need them and this is one situation where it isn't needed - perphaps my personal preference here however).


As I stated, I did not do the gas. But as gasfitters in this town go, those guys are tip top. They do good work. I myself would have hard piped it too, but it wasn't my decision.



> 5) I realize it may be a common practice for some to zap strap wiring to piping, however let me assure everyone that zap straps DO dry out and eventually become brittle enough over time to fail. I have seen it happen, and it's inevitable when the Vitodens 100 ramps up to 172 degrees to heat the indirect.


I've been doing that for over twenty years. I service what I sell. I just don't find them to be a problem. When they're REAL old they are brittle, but they're not breaking off, even on ancient clunker systems that run lots hotter than the Vitodens. I still have to cut or snip them to service things.



> 6) There is no drain down at the bottom of the indirect coil.


No there isn't. So what? How often are you going to use it? Pretty much never. It's a waste of money. Cut the pipe if you need to do something with it. It won't help with purging if that's what you're thinking - that dinky little coil flushes its air out in about two seconds with the pump on high.



> 7) I like the fact that the expansion tank is hanging - that's the best position for an expansion tank. However there is no other support seen -it's not a bad idea to put some all around or some other means.


Huh? Why? Is it going to fly away? :jester: Totally unnecessary. Once again, I (and every other boiler fitter I've ever seen) have been doing it that way for many, many years and have had no problems whatsoever.



> Also, from a servicing stand point there is no way to isolate/check/drain down the expansion tank as it currently stands. Usually a shut off valve with a drain down between the valve and tank allows the annual service tech to check the air pressure of the tank, as well as makes for a much quicker re & re when the expansion tank does fail.


Fer Pete's sake, it's a dinky little house system, not a huge apartment or commercial job. I could isolate that section, drain it, replace that tank, refill & repurge the isolated section and have it back on in ten minutes. Adding more and more parts to "make it easier to service" is just adding more and more things to go wrong later IMHO. Keep it simple.

Nobody I've ever seen or heard of checks air pressure on them - I certainly don't - never have and I don't expect I'll ever have a reason to. Check it by giving it a slap on the side - if it's heavy it's waterlogged - replace it. It's a cheap part. Spending money on fancy testing tools and labor on testing something like that is ridiculous. Waste fifteen minutes diddling around with it and you (and the customer) would be way ahead to just replace it if there's any question. If the expansion tank has failed check the pressure relief, BFP and fill valve (they may be destroyed as well).


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## Scott K

futz said:


> That pump might be _trying_ to ram all its flow through one zone valve, but that doesn't mean it's actually going to go. :laughing: As much will go as can go through that tiny valve port and then the pump will just sit there and push (like a partial deadhead). Works fine - doesn't hurt a thing - and there's no flow noise.
> 
> 
> I went to a service call last year where someone had made some adjustments and shut off one of the loops in a 2 loop zone on a manifold. The homeowner described to me the noise "it sounds like someone is driving a motorcycle down the street." I had to laugh out loud when she said that, but I isolated the flow so it could only flow through this zone, went upstairs and sure enough it sounded exactly like a motor cycle driving down the street. This was the sound of the pump ramming all its flow through one 1/2" pipe. I opened up the other loop and voila, sound gone. This COST her money.
> 
> If you try and ram all your flow through a zone, you also don't see the Delta' T's that you're supposed to as the heat in the water doesn't have as much time to do any "work." This can cause "premature" boiler cycling which puts wear and tear on ignition components, etc. I have installed dozens of these types of systems (mostly IBC's, some Lochinvar, some Viessmann) and I'm both an installer, as well as a TECA designer (I got my designers ticket after becoming an installer for a few years, and it opens up your eyes and helps you understand what is occurring in these systems - it's 6 - 4 hour saturdays at BCIT, I suggest you take the course then you won't have to rely on the boys at Sherit to determine your fate).
> 
> The "we've always done it this way" is NO excuse. The Grundfos Alpha, and other variable speed ECM pumps (Wilo Stratos, whatever Taco has to offer) is a perfect pump for constantly changing environments like a system where zone valves open and close requiring altering flows. This pump reacts to zone valves opening and closing and throttles its flow based on this. It will not provide you the exact GPM it says on your radiant layout to the tee, but with some minor balancing and adjustments it'll get pretty damn close. Not only that - it tells you how many GPM's its flowing, and how much power it is consuming on the display. I think you know Grundfos pumps are quality pumps, and this pump is no exception. After only one year in production last year they reached the million Alpha's in production mark. That's pretty damn good. I try and use them in all my installs now, even for main boiler pumps as they have constant speed settings and use half the power. It's a good upsell and the fact you can see the GPM's on the screen helps you with set up and to see what your system is actually doing. You can of course also do the old school method and figure out the head loss of the heat exchanger/system/components/piping and cross reference it to the pumps head loss chart on different speeds as well.
> 
> 
> Then Sherets' heating guys are giving me illegal boiler layouts. I very much doubt they are.
> 
> In the Teca manual Hydronic & Combo guidelines in the last section of the TECA manual, which the Sheret's heating guides are supposed to abide by when they are doing their designs, it shows/requries the use of pressure differential bypass valves as a minimum standard for a set speed pump feeding several zones. You can of course, as I mentioned above, use an Alpha instead of a fixed speed pump & diff bypass valve.
> 
> They're a pretty good last line of defense for the loops in case several other things all go wrong at once.
> 
> They are a good line of defense but I can tell you with proper hydronics practices you will not need them, BUT, like you said a good line of defence to protect floors in case something bad DOES happen.
> 
> The electrical box went on last, in the only bare piece of wall left.
> 
> It looks to me like there was an effort to pipe around the electrical box (not accusing, just saying) however there was a spot to the left where it could have gone, etc.


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## Scott K

The air separator and low-loss header are on the layout. Yes, it's a bit redundant, but the inspector will follow that thing blindly and want to see all the parts that are on the diagram.

The vent above the DHW pump intake is just to ensure that any potential air bubble that could get stuck in that elbow and/or get pulled into the pump gets removed easily. If it hits the pump then that's all she wrote - pumps can't pump air - I'd have to loosen the upper flange to get that air out. How do I know? I used to leave that vent out and had to do that flange loosening thing to get the DHW coil purged. I learned my lesson. The extra vent is necessary.

With proper hydronics practices, and tuned proper flow rates, pumps can push air around. If you keep your flow velocities to 2-4 feet per second, and do a solid pre-purge by purging each individual loop with a hose through a drain down, when you first get the system up and running the air seperator will do the rest. Generally, if you have a small pocket of air somewhere, with proper hydronics practices and set up, a pump CAN push it around a bit eventrually getting it to your air seperator and moving it out. Sure, it's not a bad idea to put air vents in high spots but let me ask you this - in your system, which I'm sure is on the basement level of a 2 or 3 story house - the top floor manifold - if you're worried about air accumulating in high spaces, how come there is no air vent there on the higher supply manifold? (or maybe you put one, but I've never seen anyone put one). How come, last week when I commissioned a Vitodens 100 feeding several top floor baseboards, with a good pre-purge, I never ONCE had to even touch the coin vents on the baseboards to remove air?


As I stated, I did not do the gas. But as gasfitters in this town go, those guys are tip top. They do good work. I myself would have hard piped it too, but it wasn't my decision.

I'm not saying these guys didn't do good work. I just found it odd they'd go to all this effort to do this and then pipe a flex connector. I did mention this was a personal preference thing. 

I've been doing that for over twenty years. I service what I sell. I just don't find them to be a problem. When they're REAL old they are brittle, but they're not breaking off, even on ancient clunker systems that run lots hotter than the Vitodens. I still have to cut or snip them to service things.

I went to a service call where there was a Tekmar controller and it had a sensor put on the boiler primary pumping (it was a conventional boiler, not a condensing boiler) to tell the controller it was safe to turn on the secondary pumps once the main boiler loop got above 150 degrees (to prevent flue gas condensation). Well the zap strap failed as it became brittle and the sensor fell off. Now there was no heat in the hosue because the boiler sensor was telling the controller that the main loop wasn't up to temperature yet, so it wouldn't start any of the secondary pumps. So the boiler just cycled, and cycled in an effort to heat up that sensor, where the zap strap had become so brittle that it had snapped off. I found this, showed the homeowner the remaining zap strap, and while I was showing her and I went to bend the zap strap to show her how brittle it was, the thing literally exploded and pieces went everywhere. I then replaced the sensor with a tiny piece of insulation and several wraps of foil tape to ensure it never happened again (wrapped completely around the pipe a few times). 

No there isn't. So what? How often are you going to use it? Pretty much never. It's a waste of money. Cut the pipe if you need to do something with it. It won't help with purging if that's what you're thinking - that dinky little coil flushes its air out in about two seconds with the pump on high. 

So you're saying this, and then you're telling me you need air vents above? Are you one of those guys who has never had a leak on your soldering too? It's not a bad idea to put a drain down, so you can drain down the entire system. Who knows what you might have to service. 
What if the tank has a bad coil and you want to isolate the secondaries to the indirect to change the tank (Bradford White has been doing some weird things with their RTV tanks lately - on the last 3 RTV 75's I've seen, the T & P tapping at the top has been cockeyed a bit - not sure what this is from, and in the same fashion - figured it's either a defect, or they're trying to allow for drainage of the T & P line?). Or what if the 15-58 fails and you want to drain down the system quickly and pump a new pump in (seeing as how there aren't any isolating ball valve flanges on the pump) and then get he system up and running versus cutting a pipe and letting water piss all over the floor. It's just a good practice to allow the drainage and/or isolation of as much of the system as you can. It's a good upsell to save them money down the road for potential service calls. 

Huh? Why? Is it going to fly away? :jester: Totally unnecessary. 

Expansion tanks fail, do we not agree? They are a wear item in any heating system right? You also agree that the goal of any heating system is to keep as much of the original water in the system as possible? To reduce the introduction of as little oxygenated water as possible, seeing as how we use some ferrous components, right? If you can isolate your expansion tank later in life, this reduces the introduction of as much fresh water as possible. It also makes for a quick replacement versus draining a good chunk of a system down and having to introduce more new fresh water, and having to ensure it's purged and operating correctly. You also can not check the air side of an expansion tank without being able to isolate it. You must remove water pressure on the tank through a drain down, to ensure you can properly measure the air. What if you get a call back for a system, and the PRV is tripping. Maybe the expansion tank hasn't failed, it's just the reducing valve isn't set properly and if you can do a isolating/drain down of just the tank itself, then you can quickly check the air pressure, adjust as needed, and the people are up and running quickly. 

Fer Pete's sake, it's a dinky little house system, not a huge apartment or commercial job. 
I have just pointed out several instances where you installed MORE than neccessary and can prove to you that what you installed was not neccessary (2 auto air vents, 1 air seperator, plus a low loss header). I could have saved you hundreds of dollars in additional parts/labour by removing those extra air removal devices for one good air seperator. You have also made an effort in some instances, to install brass parts, which are pricey. The suggestions I am making to enhance the serviceability of your system are a few extra fittings at best, all of which could have been made up by the savings I pointed out to you above, with money left in your (or the homeowners) pocket. 

Nobody I've ever seen or heard of checks air pressure on them - I certainly don't -

I used to have a lot of the same sentiments as you. When I first instsalled these things I didn't care about serviceability, or where things went, nor did I know or understand hydronics practices. But after really becoming infatuated with these machines, I started to learn. I took the TECA course. I bought John Siegenthalers book, I bought many of Dan Holohan's books, started participating on heating boards, etc. But better yet, I also had the fortune to learn from a guy who has been doing hydronics (strictly - some commercial, some residential) for 30 years - installs and service. He used to tear a strip off of me for doing things a certain way and told me to do them this way. After starting to do some service myself, and thinking he was just an A-hole all these years, I started to really see where he was coming from. He goes to all sorts of systems and he sees all sorts of different ways of doing things (some of the stuff he sees makes him bitter), and yes, there are a million ways to skin a cat, but the question is do you want to use the fur? He has many stories of the lack of serviceability or attention to hydronics practices, and it biting the customer in the arse in the pocket book. Sure, it's unavoidable that things will fail one day, but a little planning and attention to detail can make replacements painless for the homeowner and help you look good in your designs. 

You could hang the best boiler in the world on the wall (and that Vitodens 100 is one hell of a nice little boiler - what a great little simple, welll built package) with the highest AFUE which will save the customer money by reducing fuel consumption (and don't you feel good by offering customers an upgrade like this that does save the money?) but if you truly believe in saving the customer money, then serviceability, and proper hydronics design in your piping can also make the system more efficient, and serviceable, also saving further money for the homeowner. And when something goes, and it's just a quick drain down and change out, this is when you can subtlely tell the homeowner 10 years down the road that because of your attention to ensuring your systems are serviceable, you didn't have to drain down the entire system to replace something, requiring time to purge it potentially, to get it back up and running. 

You can become offended by what I have said and say I am picking on you, but I made an effort not to use "YOU" in my original post responding to your pictures, and I hope you take it as nothing but constructive. Perhaps 20 years in the trade has not made you so closed minded that you can't learn a thing or two from a young buck such as myself?


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## futz

Holy crap! This is going to take a while. :laughing::laughing:




Scott K said:


> I went to a service call last year where someone had made some adjustments and shut off one of the loops in a 2 loop zone on a manifold. The homeowner described to me the noise "it sounds like someone is driving a motorcycle down the street." I had to laugh out loud when she said that, but I isolated the flow so it could only flow through this zone, went upstairs and sure enough it sounded exactly like a motor cycle driving down the street. This was the sound of the pump ramming all its flow through one 1/2" pipe. I opened up the other loop and voila, sound gone. This COST her money.



Sounds more like a badly worn out or backward zone valve. In all the service calls I've done over the years (a LOT) I've never seen (heard) that exact one (at least I don't remember it), but I'll tell you it certainly wasn't caused by "the pump ramming all its flow through one 1/2" pipe". Doesn't work that way. I've done plenty of 1/2" zones with no diff pres bypass and the example in your anecdote just does not happen. They work just fine.

 


> If you try and ram all your flow through a zone, you also don't see the Delta' T's that you're supposed to as the heat in the water doesn't have as much time to do any "work." This can cause "premature" boiler cycling which puts wear and tear on ignition components, etc.


Again, you learned that in school probably. In practice it just doesn't work that way. The zone valve is like an orifice. It throttles flow and they work perfectly fine. I'm not just talkin out my a$$ here. I've done tons of these things and "ramming all my flow through one zone" works just fine.



> (I got my designers ticket after becoming an installer for a few years, and it opens up your eyes and helps you understand what is occurring in these systems - it's 6 - 4 hour saturdays at BCIT, I suggest you take the course then you won't have to rely on the boys at Sherit to determine your fate).


I always meant to do that, but I'm always too busy. Anyway, I have no problem with Sherets' designs. Maybe someday I'll git me some edgumication. :laughing: But probably not.

 


> The Grundfos Alpha, and other variable speed ECM pumps (Wilo Stratos, whatever Taco has to offer) is a perfect pump for constantly changing environments like a system where zone valves open and close requiring altering flows...
> ...It's a good upsell and the fact you can see the GPM's on the screen helps you with set up and to see what your system is actually doing.


They sound just fine. I'll try one on my next boiler (prefabbed one yesterday, so it's too late for that one - it goes in Monday).




> In the Teca manual Hydronic & Combo guidelines in the last section of the TECA manual, which the Sheret's heating guides are supposed to abide by when they are doing their designs, it shows/requries the use of pressure differential bypass valves as a minimum standard for a set speed pump feeding several zones.


Is that a brand new rule? Those guys usually let me know when rule changes happen. Anyway, though it might be a mighty fine rule and all, this practice of constantly adding more and more hardware to fix "problems" that aren't really problems except in some frickin engineer's mind is getting ridiculous. Ah well... If they make us do it I'll do it...




> They are a good line of defense but I can tell you with proper hydronics practices you will not need them, BUT, like you said a good line of defence to protect floors in case something bad DOES happen.


Also they're on the layout, so I have to put one.


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## futz

Scott K said:


> With proper hydronics practices, and tuned proper flow rates, pumps can push air around. If you keep your flow velocities to 2-4 feet per second, and do a solid pre-purge by purging each individual loop with a hose through a drain down, when you first get the system up and running the air seperator will do the rest. Generally, if you have a small pocket of air somewhere, with proper hydronics practices and set up, a pump CAN push it around a bit eventrually getting it to your air seperator and moving it out.



That's all very nice, but you try it sometime with an elbow like that turning down to a pump pumping down. You can purge with a hose all day long and it'll still have a bubble in that elbow. The pump will pull till it sucks the bubble, then it stops pumping and windmills, and your bubble is still there. Then it'll bounce up and down and drive ya nuts forever. A cheap AAV cures it. I know what you'll say next: "Put the pump on the return!". That's even worse. Pumps on returns are nothing but trouble, believe me!



> Sure, it's not a bad idea to put air vents in high spots but let me ask you this - in your system, which I'm sure is on the basement level of a 2 or 3 story house - the top floor manifold - if you're worried about air accumulating in high spaces, how come there is no air vent there on the higher supply manifold? (or maybe you put one, but I've never seen anyone put one).


This one is all on the ground floor. Electric heat up. Owner's decision - not mine. I use coin vents on the manifolds. They get used once, for the first big rough purge, and then never again.



> How come, last week when I commissioned a Vitodens 100 feeding several top floor baseboards, with a good pre-purge, I never ONCE had to even touch the coin vents on the baseboards to remove air?


I rarely use the coin vents on baseboards either. They usually purge out pretty easy.




> I went to a service call where there was a Tekmar controller and it had a sensor put on the boiler primary pumping (it was a conventional boiler, not a condensing boiler) to tell the controller it was safe to turn on the secondary pumps once the main boiler loop got above 150 degrees (to prevent flue gas condensation). Well the zap strap failed as it became brittle and the sensor fell off. Now there was no heat in the hosue because the boiler sensor was telling the controller that the main loop wasn't up to temperature yet, so it wouldn't start any of the secondary pumps. So the boiler just cycled, and cycled in an effort to heat up that sensor, where the zap strap had become so brittle that it had snapped off. I found this, showed the homeowner the remaining zap strap, and while I was showing her and I went to bend the zap strap to show her how brittle it was, the thing literally exploded and pieces went everywhere. I then replaced the sensor with a tiny piece of insulation and several wraps of foil tape to ensure it never happened again (wrapped completely around the pipe a few times).


That's a nice story, but strapping wires on with cable ties is a lot different from strapping sensors on with them. That's just stupid. If my wires break loose (they won't - I know from experience) nothing bad happens. It just maybe looks ugly - probably not even that. And what makes you think frickin foil tape is going to last forever? :laughing: Strap it on with something permanent!




> So you're saying this, and then you're telling me you need air vents above?


Air vent (singular). Yes, I am saying that.



> Are you one of those guys who has never had a leak on your soldering too?


Yes. I know how to solder. Been doing it since I was seven years old. I don't get leaks.



> It's not a bad idea to put a drain down, so you can drain down the entire system. Who knows what you might have to service.





> What if the tank has a bad coil and you want to isolate the secondaries to the indirect to change the tank (Bradford White has been doing some weird things with their RTV tanks lately - on the last 3 RTV 75's I've seen, the T & P tapping at the top has been cockeyed a bit - not sure what this is from, and in the same fashion - figured it's either a defect, or they're trying to allow for drainage of the T & P line?). Or what if the 15-58 fails and you want to drain down the system quickly and pump a new pump in (seeing as how there aren't any isolating ball valve flanges on the pump) and then get he system up and running versus cutting a pipe and letting water piss all over the floor. It's just a good practice to allow the drainage and/or isolation of as much of the system as you can. It's a good upsell to save them money down the road for potential service calls.


 
The tank loop has isolation valves. The entire radiant section has iso valves too. There's not all that much water in the boiler/tank coil/lo-loss. I could drain it all into a five gallon bucket (maybe another quarter bucket) and not get any on the floor. Could even re-inject if if the bucket was clean and I wanted to (I don't). Cutting that bottom pipe and catching a splash of water would take less time than dealing with a worn out old boiler drain killed by the heat. I still say keep it simple. That system is very serviceable. I do lots of service and I know what works and what's a waste of time and money, especially when these systems get extremely old and crotchety.




> Expansion tanks fail, do we not agree? They are a wear item in any heating system right? You also agree that the goal of any heating system is to keep as much of the original water in the system as possible? To reduce the introduction of as little oxygenated water as possible, seeing as how we use some ferrous components, right? If you can isolate your expansion tank later in life, this reduces the introduction of as much fresh water as possible. It also makes for a quick replacement versus draining a good chunk of a system down and having to introduce more new fresh water, and having to ensure it's purged and operating correctly.


Isolation valves on radiant section and tank section, remember? There's way less than five gallons of water in the boiler/lo-loss. The lo-loss has a drain at the low point. That whole section is easily repurged without introducing more than a small bubble into the radiant and tank sections. Changing that exp tank will be very simple. At that age I'd probably slap in a couple new AAVs on the tank and radiant loops anyway, and they'd take care of the aforementioned small bubble.



> You also can not check the air side of an expansion tank without being able to isolate it. You must remove water pressure on the tank through a drain down, to ensure you can properly measure the air. What if you get a call back for a system, and the PRV is tripping. Maybe the expansion tank hasn't failed, it's just the reducing valve isn't set properly and if you can do a isolating/drain down of just the tank itself, then you can quickly check the air pressure, adjust as needed, and the people are up and running quickly.


Like I said before, I just don't bother with checking air pressure on those things. If the tank is heavy or if there's any question at all just bang in a new one - they're cheap, compared to the cost of having me there. And like I said too, I could change that tank in ten minutes without more hardware that would likely not work anyway when it got to that age. Boiler drains (sediment faucets) are really bad for just completely failing in the heat. They're fine till you touch them. Then it's replacement time. So now you're draining that section anyway - why bother putting them on in the first place. Sure, I could put ball valves... But all that extra crapola just to maybe save a couple minutes someday. Not worth it.




> You can become offended by what I have said and say I am picking on you, but I made an effort not to use "YOU" in my original post responding to your pictures, and I hope you take it as nothing but constructive. Perhaps 20 years in the trade has not made you so closed minded that you can't learn a thing or two from a young buck such as myself?


I'm not offended at all. I do even take _some_ of your advice. On a previous boiler post you recommended those isolating ball valve flanges. I had used those in the past, but had forgotten they even existed. I started buying and using them again. Thanks for the reminder.


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## Scott K

Holy crap! This is going to take a while. :laughing::laughing:
Sounds more like a badly worn out or backward zone valve. In all the service calls I've done over the years (a LOT) I've never seen (heard) that exact one (at least I don't remember it), but I'll tell you it certainly wasn't caused by "the pump ramming all its flow through one 1/2" pipe". Doesn't work that way. I've done plenty of 1/2" zones with no diff pres bypass and the example in your anecdote just does not happen. They work just fine.

Again, you learned that in school probably. In practice it just doesn't work that way. The zone valve is like an orifice. It throttles flow and they work perfectly fine. I'm not just talkin out my a$$ here. I've done tons of these things and "ramming all my flow through one zone" works just fine.

This has NOTHING to do with where I learned it. It has to do with good hydronic practice.

There were no zone valves for this sytem. It had a manifold station in the mechanical room 2 floors down. The manifold system with actuators (old rehau actuators) fed multiple 3/4" heating mains, which went to pre-built copper manifold stations with those dahl adjustable balancing valves with 1/4 turn shut off (with the allen key) for each loop. As soon as I opened up the other loop, the sound went away.

I always meant to do that, but I'm always too busy. Anyway, I have no problem with Sherets' designs. Maybe someday I'll git me some edgumication. :laughing: But probably not.

They sound just fine. I'll try one on my next boiler (prefabbed one yesterday, so it's too late for that one - it goes in Monday). 

There is no reason you couldn't put one on your boiler NOW and use the 15-58 you have in place for another job. It's a straight swap out, although you will have to wire a plug receptacle instead of hard wiring it off of the controls to plug the Alpha into (they have line corded adapters for Alpha's coming out soon - if youw want an explanation of why you can only plug them in up until now, I can explain). You WILL love this pump, and if you have someone explain or take the time to learn the settings, you'll use them all the time. If you buy 2 Alpha's right now at Emco, they'll cut you a deal of $20 off per pump. So they're normally about $250 each - now $230-ish each if you buy 2. Use one for the next job, one for this job, etc. 

Is that a brand new rule? Those guys usually let me know when rule changes happen. Anyway, though it might be a mighty fine rule and all, this practice of constantly adding more and more hardware to fix "problems" that aren't really problems except in some frickin engineer's mind is getting ridiculous. Ah well... If they make us do it I'll do it...

My TECA manual is over 2 years old right now, but I can tell you this "rule" has been out for much longer then that. How long, I can't say, but I know I've seen much older mech rooms with them in it (10-15 years old-ish). Using diff-by passes is a lot having a car at full throttle and using the brakes to slow it down. It works, but now with the Alpha, there is better option. AS each actuator opens and closes, the pump adjusts it's flow rate to accomodate the extra GPM needed to flow through that zone to heat it. Not using anything is like trying to ram your semi through a tunnel that can only fit a car. 

Also they're on the layout, so I have to put one.


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## futz

Scott K said:


> There were no zone valves for this sytem. It had a manifold station in the mechanical room 2 floors down. The manifold system with actuators (old rehau actuators) fed multiple 3/4" heating mains, which went to pre-built copper manifold stations with those dahl adjustable balancing valves with 1/4 turn shut off (with the allen key) for each loop. As soon as I opened up the other loop, the sound went away.



Ah. Totally different thing then.

 


> There is no reason you couldn't put one on your boiler NOW and use the 15-58 you have in place for another job.


This boiler is for a spec house. At $200 extra for an Alpha it's just not going to happen on this one. Next time I do a high efficiency system tho...


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