# I'll start



## RealLivePlumber (Jun 22, 2008)

I have a Weil Mclain Cgs boiler, with 2 zone fin and tube baseboard. 

I am going to install a Taco outdoor reset, and replace the zone valves with circulator pumps. 

My questions are what is the best way to pipe the bypass piping, to ensure 150 degree return water temp. Should I just use ball valves and throttle them? Or should I do a primary/secondary loop with a third pump?

Also, where should the sensor for the outdoor reset be placed? I called Taco twice, no return call, and not in the manual.


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## OldSchool (Jan 30, 2010)

It sounds like you want to do an injection type system. If that is the case you would need one main circ pump. And pump for each zone. So you would have a primary loop then all other loops off that. There would be no bypass.


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## gladerunner (Jan 24, 2009)

and the sensor should be in a shaded area, out of direct sunlight.
you don't want any solar gain


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## Protech (Sep 22, 2008)

I have no friggin clue what you guys are talkin about :confused1:

What is an "outdoor reset"?

What is "bypass piping" for?


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## OldSchool (Jan 30, 2010)

Protech said:


> I have no friggin clue what you guys are talkin about :confused1:
> 
> What is an "outdoor reset"?
> 
> What is "bypass piping" for?


*Outdoor reset or indoor/outdoor control* is use to measure the outdoor temperature to set the boiler water temperature according to the heat loss for the given outdoor temperature.

*Bypass* is used to raise the return water temperature to the boiler inorder that you do not have to low of a water temperature that would shock the boiler and cause it to crack. *"Thermal Shock"* 

This is primarily a concern with infloor heating return going back into the boiler. 

Cast Iron and steel boilers can't withstand the temperature difference.


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## PLUMBER_BILL (Oct 23, 2009)

RealLivePlumber said:


> I have a Weil Mclain Cgs boiler, with 2 zone fin and tube baseboard.
> 
> I am going to install a Taco outdoor reset, and replace the zone valves with circulator pumps.
> 
> ...


??? I always thought that the outdoor reset control was to 
anticipate the change in outdoor temperature and change the temps the boiler would need to supply the radiation. Why are you striving for 150 degree return water. You sure you don't mean supply water?


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## Miguel (Aug 10, 2009)

PLUMBER_BILL said:


> ??? I always thought that the outdoor reset control was to
> anticipate the change in outdoor temperature and change the temps the boiler would need to supply the radiation. Why are you striving for 150 degree return water. You sure you don't mean supply water?


I think he's trying to eliminate condensing in the flueways of the CI boiler sections by keeping the return temps up. 
150° would do it for sure but 120° - 130° return temps are usually quite sufficient. 150° is quite often good supply water temperature during balmy days.

RLP, there's many ways to maintain return water temps to the boiler but in my experience the primary/secondary loops are the most cost efficient and reliable means going, 8 times outta 10. IMHO anyway.

It also leaves the door open to incorporate loops of different temp requirements either now or down the road (say you want add low temp radiant or mid temp DHW, etc).

Um, also, if I'm not mistaken the CGs shipped with a triple aquastat with a pump controller built in. Not the best way but it does work and helps prolong the life of the boiler.


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## Miguel (Aug 10, 2009)

Protech said:


> I have no friggin clue what you guys are talkin about :confused1:
> 
> What is an "outdoor reset"?
> 
> What is "bypass piping" for?


:laughing::laughing::laughing:

With some of the winters you guys have been having you made want to find out.


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## RealLivePlumber (Jun 22, 2008)

Thanks for the suggestions. I am just getting into this fancy stuff. We always did it the old fashioned way, So I figure I might as well learn on my dime. 

I spoke to Weil Mclain, and they would like to see 150 degree minimum return water. 

So with primary/sec piping, 1 pump circultates through the boiler, and the zones are off of that loop? Anybody got a good piping diagram?

Miguel, the Cgs didn't ship with a triple, it is a single.( Cold start.) No DHW, either.


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## OldSchool (Jan 30, 2010)

Best way... primary loop ... then tee off supply injection one after the other.... then tee in returns..... This way all loop get the same water temperature.


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## futz (Sep 17, 2009)

RealLivePlumber said:


> I spoke to Weil Mclain, and they would like to see 150 degree minimum return water.


They're just playing safe. We're required to maintain no lower than 135F return temperature. Flue gas condensation starts somewhere in the 120F to 130F range - I forget the exact number.


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## Miguel (Aug 10, 2009)

OldSchool said:


> Best way... primary loop ... then tee off supply injection one after the other.... then tee in returns..... This way all loop get the same water temperature.


I hate to disagree but I used to think the same way, if what you mean is first in last out. Tie in your secondary loops with the S/R TEES no more than 6" apart, start with your highest temp and work your way down around the primary. ie: tube & fin baseboards come off first, S&R, then DHW to your exchanger (if used) followed by radiant or CI rads (old style). I usually use an aquastat set to my min. return water temp and mounted last (back into the boiler) connected in series to the secondary pumps to make sure the boiler never condenses.



RealLivePlumber said:


> Miguel, the Cgs didn't ship with a triple, it is a single.( Cold start.) No DHW, either


My bad. I was thinking of the CGa (old style draft hood unit) but I think even those don't ship with a triple anymore.
If no DHW then great! Less controls to work with. 
But the beauty of the primary/secondary is that you can install plugged TEEs from the get-go for future consideration.


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## OldSchool (Jan 30, 2010)

Miguel said:


> I hate to disagree but I used to think the same way, if what you mean is first in last out. Tie in your secondary loops with the S/R TEES no more than 6" apart, start with your highest temp and work your way down around the primary. ie: tube & fin baseboards come off first, S&R, then DHW to your exchanger (if used) followed by radiant or CI rads (old style). I usually use an aquastat set to my min. return water temp and mounted last (back into the boiler) connected in series to the secondary pumps to make sure the boiler never condenses.


Sorry cant agree with you there. When injection type system first came out they tried to get everyone to do it as you described. But now logic has over ruled this. 

The last training coarse I attended in December from wirsbo. They now say that this is a much better way that going side by side with supply and return on loop. The way you describe it will keep lowering water temperature for every loop that follows.

The way I described it would be supplies first then returns. This way all loops get same water temperature. It does take more material and labour this way but it has been proven to be the best method. 

:thumbsup:


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## nhmaster3015 (Aug 5, 2008)

RealLivePlumber said:


> I have a Weil Mclain Cgs boiler, with 2 zone fin and tube baseboard.
> 
> I am going to install a Taco outdoor reset, and replace the zone valves with circulator pumps.
> 
> ...



You should do primary secondary yes. Either that or hydronic separator. In any case the sensor still goes on the primary outlet. Other options would be 3 way zone valve or an injection system but both of those are expensive and overkill for a residential 2 loop job.


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## trick1 (Sep 18, 2008)

RealLivePlumber said:


> I have a Weil Mclain Cgs boiler, with 2 zone fin and tube baseboard.
> 
> I am going to install a Taco outdoor reset, and replace the zone valves with circulator pumps.
> 
> ...


I place the sensor in the secondary loop (system loop) on the supply. That way, the outdoor reset controller can sense what the system wants, not the boiler. The reset controller such as the Argo AMB or other type of reset controller offers return temperature protection.

The hydraulic separator/low loss header is an awesome way to separate the boiler circuit from the system circuit and provide the flow rates needed for the system. Mixing occurs in the separator and the sensor, placed after the separator, can sense the needs of the system and adjust the temperature.


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## njoy plumbing (May 19, 2009)

RealLivePlumber said:


> Thanks for the suggestions. I am just getting into this fancy stuff. We always did it the old fashioned way, So I figure I might as well learn on my dime.
> 
> I spoke to Weil Mclain, and they would like to see 150 degree minimum return water.
> 
> ...


 RLP, just a suggestion, try googling your boiler site and alot of times they will have pipe schematics suggested for the differant scenario's. I personally use mod cons 95% of the time so there are specific layouts for these and are supplied to you. also your hydronic supplier can give you a suggested schematic based on head loss, etc...


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## Miguel (Aug 10, 2009)

OldSchool said:


> Sorry cant agree with you there. When injection type system first came out they tried to get everyone to do it as you described. But now logic has over ruled this.
> 
> The last training coarse I attended in December from wirsbo. They now say that this is a much better way that going side by side with supply and return on loop. The way you describe it will keep lowering water temperature for every loop that follows.
> 
> ...


Well I can't disagree with that method. It's tried and true, but what I've found to be better is a primary loop with secondary loop TEE groups taken off in order of their temp requirements, S&R. ie: first set seeing supply water first would be for baseboards, fan coils, etc. Next would be DHW, and finally radiant or other low temp use.
But when you get to piping your zones *then* take off all the supplies and dump the returns after the last zone.

In most cases, even fairly complex situations, I generally only take one or two S&R pairs off the primary. 3 max. This is what I've found to work best for me anyway.

RLP, check page 19 in your manual (http://www.weil-mclain.com/en/multi...boilers/gas-boilers/cgs/cgs_boiler_manual.pdf) <-- 8MB

Piping diagram 3d is a close approximation to what I'm talking about here. The balancing valves *7a *& *7b* I've found to be useless unless it's strictly a low temp system, but with or without them this kind of arrangement works very well for both high and low temp systems and perfect for mixed systems when using a conventional CI or steel boiler. I'll also put an aquastat on the return side of the primary loop and use it to limit the secondary pump(s) and/or zone valves.

Tekmar are my fave controllers but these days there're lots to choose from for practically any application.

Sometimes I'll install some full sized TEE's for future consideration and just plug them. More than once I've come back later because the HO or new owner wants to heat the garage or install radiant in a sun room, etc.

Somemore food for thought.


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## RealLivePlumber (Jun 22, 2008)

Thanks alot, guys. I really appreciate it!

That diagram is what I was thinking. I don't really like the idea of those valves, 7a and 7b.

I don't like throttling ball valves. I think I'll put a primary pump, as well as 2 zone pumps. 

I just gotta figure out how to wire and control the primary pump. I intend on using a Taco SR504exp relay. Taco has alot of diagrams available, I'll look at those. 

Unless I'm thinking wrong?:blink:


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## njoy plumbing (May 19, 2009)

RealLivePlumber said:


> Thanks alot, guys. I really appreciate it!
> 
> That diagram is what I was thinking. I don't really like the idea of those valves, 7a and 7b.
> 
> ...


 I use the same taco manager with that system, works excellant! Check out triangle tube web site.:excl:


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## jointwiped (Apr 5, 2010)

OldScool's Suggestion seems to me to be the best way to go. IMO

When I moved into this pos house 34 years ago, it had forced air heat. 
Now Growing up in NEPA with Steam and Coal fired systems none the less, The DW had a hard time adjusting and even keeping warm with air blowing on her at 110° at some times. ...hahaha... I loose!

I knew I had to do something...so I ripped out the dirty ducts and cruddy furnace...and installed a *free* boiler that my Old Man got from a house that was in a fire. The boiler was a little 100,000 Nat Gas American Standard ...probably 62% efficient. It served its purpose because the gas was cheap then..and daddy was working OT, and the $140.00 bill was a mere bag af shells! ha ahahahaha

Anyway...I Primary secondary looped with 9 zones...all zone valves (mix and match brands from job leftovers) and piped the job Reverse Return. Oh! it was a rocket looking job, and looked like a process boiler system in a brewery! Ha Ha

That system worked best...everyone had their own thermostat, and I didn't have to listen or see any tears  about who's hot or cold. OK?

When I installed the Bbd...fintube, standard capacity, except high capacity in the bathrooms, I *oversized* the radiation to max. This way I could get enough btu ouput to heat the rooms with a lesser SWTemp.
Using Z-valves and secondary pumping...I was able to heat the house easily with 160° water (supply) oh until say 25° O.D.Temp. Then I would have to manually go down to the boiler room and jerk the aquastat (limit) upwards to 170°.

That became a PITA.....so I then installed a Outdoor Reset controller (Honeywell T-7500 I off the record think it was), and wow! No more running to keep messing with the discharge water temps according to O.D Temp.

That system is still in use today! But...In 1997,....I trashed the atmospheric burner boiler, and Installed a (don't laugh) Hydrotherm Hydro-Pulse A-150. I had it since "85" in my shed. It was one of three that I installed in a custom home that ran for three days, and the homeowner ($$Big Bucks) said..."What's that noise?"...and I said,"Your Boilers!"
He said,"Are they supposed to make that noise?"...yes I said!".....well he said,.....Get them the f out of here NOW!

After *his call* to the architect..the next day I was ripping them out and installing 3 Burnham's. Ha Ha Ha

Anyway...I will get into the pppppulse thing at a later time..and as a Certified Hydro-pulse Man...Oh do I have stories! ..

To summarize though...R L P ...the two separate pumps off the primary boiler pumping would be a good choice for you.
For me, I would stay with my zone valves (9). I don't think I have enough electricity in this house to run 10 circ's. Ha Ha 


BTW...I don't remember which brand controller, Tekmar? maybe?...but you can have a Indoor sensor that will shift the control of water temp. working the system as a optimizing type control,;that would ramp up the boiler temp to accomodate the time to reach setpoint at the indoor sensor; espscially coming out of Reduced Temp Night Seback! ....Tricky to set up though, and usually better for appartment multiunit systems like garden appartments or etc. ....... "The End" ...:blink: yeah jimmy...s.t.f.u.


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## RealLivePlumber (Jun 22, 2008)

Thanks for the advice. Now that it's getting warmer, I'll get to piping!


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