# critique this hydronic system



## roving plumber (Apr 25, 2011)

Looking for imput on a hydronic system I hooked up for a friend. To be fair I didn't design it, it's basically an identical system to his last one that he had for 14 trouble free years. I'ts a 50 gal 38k btu nat gas, honeywell 1" air eliminator, grundfos 15-58, st-25 expansion tank and a taco single zone controller.
Hope I can get the pics to upload. the couple issues the system is having is erratic pressure, it was at 10 the other day when I left and the supply temp was only up to 90. The homeowner informed me the stat satisfied and shutoff then the pressure jumped to 42, I'm not super worried about the pressure seeing how it's on a domestic tank. The other issue is the fluid in the tank has been heating for a couple days and hasn't reached 100 degrees yet, the flame didn't really chnge much from a low setting to high. I can't imagine it's a gas volume problem it comes in 1" reduces to 3/4" then close nipple to 1/2"x3/4" bullhead tee feeding it and the domestic. I am thinking of replacing the boiler drain on the return side with an automatic air bleeder as I think the pressure fluxuation could be caused by air, although the system was running smooth no gurgling or cavitation. I should also mention the system is filled with cryotek 100 at 50% dillution.
Any thought or suggestins are appreciated, thanks.


----------



## Debo22 (Feb 15, 2015)

I don’t know much about hydronic systems, but if you’re not seeing a fluctuation between high and low fire, use a manometer to check gas pressure. I’ve seen bad Gas Co regulators, check the inlet and outlet of the gas valve.

I had a water heater that the pilot kept going out intermittently, water heater gas valves don’t have an inlet port just an outlet test port. I put my manometer on the furnace gas valve inlet to test, pressure went to 18” water column when nothing was in use to pretty much zero when something called for gas.

Since you asked for a critique, no PVC on T&P


----------



## roving plumber (Apr 25, 2011)

Dang, I believe you're right. I got partially tricked on that one, his brother had started running them and I finnished. Still no excuse for a rookie mistake. Thanks for the input on the gas, I think I'll have him get the gas co. to come make sure the meter is good. I need to impliment better liability policies for when people just want a price for "just labor."


----------



## ken53 (Mar 1, 2011)

*cryotek*



roving plumber said:


> Looking for imput on a hydronic system I hooked up for a friend. To be fair I didn't design it, it's basically an identical system to his last one that he had for 14 trouble free years. I'ts a 50 gal 38k btu nat gas, honeywell 1" air eliminator, grundfos 15-58, st-25 expansion tank and a taco single zone controller.
> Hope I can get the pics to upload. the couple issues the system is having is erratic pressure, it was at 10 the other day when I left and the supply temp was only up to 90. The homeowner informed me the stat satisfied and shutoff then the pressure jumped to 42, I'm not super worried about the pressure seeing how it's on a domestic tank. The other issue is the fluid in the tank has been heating for a couple days and hasn't reached 100 degrees yet, the flame didn't really chnge much from a low setting to high. I can't imagine it's a gas volume problem it comes in 1" reduces to 3/4" then close nipple to 1/2"x3/4" bullhead tee feeding it and the domestic. I am thinking of replacing the boiler drain on the return side with an automatic air bleeder as I think the pressure fluxuation could be caused by air, although the system was running smooth no gurgling or cavitation. I should also mention the system is filled with cryotek 100 at 50% dillution.
> Any thought or suggestins are appreciated, thanks.


Cryotek at 50% cold be a little strong up here they don't recommend over 30% percent for heating it reduces the exchange of heat. The stand alone water heater for space heating was banned here 10 years ago, but I think it's still code were you are. One thing to check if you are getting weird gas pressures is the flex connector. 
Oh, and I think most gas codes call for a dirt pocket at every appliance here the inspector will defect it if it's before the flex connector. Check the fittings on your flex if it's stamped "do not reuse" you need a proper union at the gas valve.
The T&P thing, we can use PVC, but the glue can supporting it I don't think is code.
I was an inspector for a few years, so I'm picky and codes do differ from place to place.

I does look like nice clean work.


----------



## roving plumber (Apr 25, 2011)

ken53 said:


> Cryotek at 50% cold be a little strong up here they don't recommend over 30% percent for heating it reduces the exchange of heat. The stand alone water heater for space heating was banned here 10 years ago, but I think it's still code were you are. One thing to check if you are getting weird gas pressures is the flex connector.
> Oh, and I think most gas codes call for a dirt pocket at every appliance here the inspector will defect it if it's before the flex connector. Check the fittings on your flex if it's stamped "do not reuse" you need a proper union at the gas valve.
> The T&P thing, we can use PVC, but the glue can supporting it I don't think is code.
> I was an inspector for a few years, so I'm picky and codes do differ from place to place.
> ...


Thanks for the input ken53, the inspector had come by after I had hooked up the gas so we could have the gas co remove the lock. So I guess he didn't see anything he was too concerned with. In hindsight I see that I could have easily installed the dirt leg at the unit, the flex was new and I don't recall the exact number but at 3' that flex was rated at or almost double the input rating of the burner. I talked with the homeowner yesterday and the supply temp was still around 90 with the gas valve still on very hot, I guess I should research the heat transfere in glycol problem you mentioned. His last house just ran water, I can't imagine that glycol not getting hot after 2-3 days of running. I figured I'd take some ribbing for having my temp t&p support in the pic :blush: 
Thanks again for the input, I think constructive criticisms can help us become better craftsman.


----------



## JohnnieSqueeze (Mar 23, 2016)

Im currently buying parts and planning a system for my own house. 

Never done it. I plan to make my own control board with pumps, expansion tank etc because they are very expensive at the box stores. 

I appreciate and links to designs. I dont know where I need check valves, pressure reducing valves etc. Totally green to this system. 


Sent from my iPhone using Tapatalk


----------



## ShtRnsdownhill (Jan 13, 2016)

where is the expansion tank? not being there to see the whole system piped can you draw a diagram of the piping? obviously its NOT the same as the system he had because you are having issues with it...38k is not enough to heat the radiant if its taking days and not coming up to temp..


----------



## roving plumber (Apr 25, 2011)

*hydronic system in response to Johnnie Squeeze*

I'm no expert but I have piped a fair amount of hydronic systems. some good information can be found at Caleffi, Taco comfort solutions, PMmag.com and Emerson Swan to name a few, I have watched webinars and read articles from these sites. Depending on your boiler, and tube in slab or baseboard will obviously dictate how your system is set up. Some supply houses have sales guys that can run calculations for your system for little to no charge if you're purchasing product from them. Air elimination is a point of concern for me, I always (almost, broke my own rule on my last install) try to put air eliminators at any high point in the system where air can get trapped. Another consideration is water quality, if you fill your system with water it would be wise to add inhibitors(for the minerals) also if installing a condensing boiler consider a condensate nuetralizer.
Do your research and keep it as simple as possible, that's my .02 worth.


----------



## roving plumber (Apr 25, 2011)

ShtRnsdownhill said:


> where is the expansion tank? not being there to see the whole system piped can you draw a diagram of the piping? obviously its NOT the same as the system he had because you are having issues with it...38k is not enough to heat the radiant if its taking days and not coming up to temp..


Expansion tank is under the platform, it's piped into the air seperator. As stated it is "basically" the same. The other house had tube in the upstairs with multiple zones, this one is only tubed on the first floor with one zone. I don't think it was the right way to go but again I was just asked to pipe it, according to the manual with the water heater the "very hot" setting should yeild approx 160 degree.


----------



## breplum (Mar 21, 2009)

On any system with a pump I recommend hosebibb on both sides of the pump. It’s the perfect way to get air out of the system. Just add fip tees now, And in the future if you have access Webstone makes those flange adapters with multifunction drain/purge built-in. 
Byam and on her as well because you can’t Troubleshoot gas equipment without one.
For home heating a conventional Water Heater is so inefficient that it is banned in almost the entire United States to use as a heat source. 


Sent from my iPhone using Tapatalk


----------



## roving plumber (Apr 25, 2011)

At this point I'm thinking an option may be to pull the check valve out of that pump, thought being that at the time the pump is not running any air should migrate up the supply pipe through the pump and out the air seperator. Any downside to removing the check valve in a system set up like this?


----------



## ShtRnsdownhill (Jan 13, 2016)

roving plumber said:


> Expansion tank is under the platform, it's piped into the air seperator. As stated it is "basically" the same. The other house had tube in the upstairs with multiple zones, this one is only tubed on the first floor with one zone. I don't think it was the right way to go but again I was just asked to pipe it, according to the manual with the water heater the "very hot" setting should yeild approx 160 degree.



your missing the point...if the slab pulls more btus than the water heater can put into the water you will NEVER get 160 degrees...I have designed and piped hundreds of hydronic systems and they all work fine...what exactly is your problem here? air in the system or no heat due to lack of temp in the water or something else?
did you ever hear of Dan Holohan?


----------



## ken53 (Mar 1, 2011)

ShtRnsdownhill said:


> your missing the point...if the slab pulls more btus than the water heater can put into the water you will NEVER get 160 degrees...I have designed and piped hundreds of hydronic systems and they all work fine...what exactly is your problem here? air in the system or no heat due to lack of temp in the water or something else?
> did you ever hear of Dan Holohan?


He's right what works one place may not in another. I looked up your Design temperature -12 that is and average microclimates can give you trouble. You say there is tube tube heat what kind, fin tube baseboard, Radiant floor tube.
If you are heating a slab how close is the water table if it's close you can triple the heat load check the sump pit if there is one.
The other thing I haven't noticed is, are you heating the same floor area what is your tube spacing. 
Clock your meter dial see if the water heater is putting out the full BTU.

You might have bought yourself a problem.


----------

