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Old 12-03-2011, 09:31 AM   #1
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Need help with finishing touches on radiant heat system


Hello all,
As a few of you may know, I've been planning and building a whole-house Radiant heat system for about 1.5 years. The basic premise is a primary circuit fed by a Weil-McClain Ultra-80 boiler, and three secondary circuits, one for each floor of the house. Each secondary is controlled by its own thermostat, and the system is controlled by a TACO 503 switching relay.

Details: The basement is poured concrete on PEX-AL-PEX, the first floor is PEX-AL-PEX stapled up under 1.5" of hardwood with aluminum heat transfer plates, and the second floor is O2 barrier PEX going to 4 different radiators. There is also a 4-way mixing valve for the basement circuit to lower the temperature of the supply water. system temperatures atr ~140-150 degrees, and the basement circuit is ~95 degrees. I made my own manifold for the circuit on the first floor circuit out of copper, but purchased "real" brass manifolds for the basement and the second floor circuit. I bought three new TACO 007 circulators, and the fouurth is recycled from the previous gravity-fed system (completely gone). The recycled 007 is on the second floor circuit...

So I finally have the whole thing set up and tried to run it yesterday for the first time.... I have come across two problems, and I would like advise on how to proceed....

1. Leaks on all the brass manifolds. I have all the manifolds threaded through brass nipples (one manifold is attached to galv. steel) with plumbers tape. The worst offender is the highest manifold in the system. I drained the system, removed the lines, and tried to tighten the manifold with a 20" wrench... it simply will not tighten anymore and still leaks. It is a very slow leak but a leak nontheless. I let the system run since yesterday, and the leak has continued, and now I'm seeing leaks at all the brass manifolds. I tried to patch it with caulk, and then that strechy black plumbers fixit tape. Nothng seems to work. I'm also getting a leak at one of the PEX-manifold connections. This is a compression fitting and it simply will not tighten any more (the rest are fine) What do I do?

2. No hot water to the second floor. The basement and 1st floor lines are working fantastically (1st floor is warm, something I couldn't achieve with our forced air system). I think the recycled circulator is not functioning properly... I've heard about "burping" the circulator, but I'm not sure how to do this. I'm pretty sure there is no air in the lines, and I have a vent right next to the circulator. I am attaching pictures. I know I should have placed valves on either side of every circulator but for my set-up that was just too expensive (~$15/valve x 4). Does it need to be replaced? How can I tell if the motor is turning?

Thanks for your help.


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Old 12-03-2011, 10:27 AM   #2
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Need help with finishing touches on radiant heat system


yikes....

1. There's no auto-fill for make-up water with backflow preventer. Im assuming the blue pex is your fill line and the gate valve is how you filled the system.

2. Caulk, rubber tape, etc., is not the proper way to fix a leak. Disassemble the fitting and inspect. If the threads are alright, use some leak-lock, a few wraps of teflon, or both.

3. What's the pressure in the system... Also, a 007 may not have the necessary head pressure to push through 1/2" pex and second floor radiators. Is that check valve installed in the right direction?

4. Is this supposed to be a primary/secondary piping setup? It's not done properly.

5. Drain valves should be placed on the return of each circuit before it dumps back into the main to purge air out when filling.

6. 150 degree water running through the plates under the first floor hardwood is awfully hot. You're asking for trouble with the hardwood. I know it feels nice on the tootsies, but the floor isnt really supposed to be 85 degrees.

7. Put your hand on the circulator, you'll feel the vibration if it's spinning.

Honestly, I'd pull that all apart and start over.

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Old 12-03-2011, 10:48 AM   #3
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Need help with finishing touches on radiant heat system


why did you use galvinized piping you should of did all copper or black to the headers anyplace you have copper to galvinized with a boiler supplying 170F-180F water you are going to get electrolysis over the coming years you better get some flood insurance...
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Old 12-03-2011, 11:06 AM   #4
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Need help with finishing touches on radiant heat system


Thanks for the response...

Quote:
Originally Posted by Splinter View Post
1. There's no auto-fill for make-up water with backflow preventer. Im assuming the blue pex is your fill line and the gate valve is how you filled the system.
I did not install and auto-fill. Is it really necessary? I can just add water from the gate valve when/if system pressures run low.

Quote:
Originally Posted by Splinter View Post
2. Caulk, rubber tape, etc., is not the proper way to fix a leak. Disassemble the fitting and inspect. If the threads are alright, use some leak-lock, a few wraps of teflon, or both.
Thanks. How can I make sure the threads are OK? These were new manifolds. The threads were intact. I will have to find "leak lock"- I've nver used this before.


Quote:
Originally Posted by Splinter View Post
3. What's the pressure in the system... Also, a 007 may not have the necessary head pressure to push through 1/2" pex and second floor radiators. Is that check valve installed in the right direction?
The check valve is installed in the right direction, as is the circulator. I did the calculations and the 007 did provide enough head to bring the hot water up 10 feet. There is no difference in the temperature of the lines with the circulator on or off.

Quote:
Originally Posted by Splinter View Post
4. Is this supposed to be a primary/secondary piping setup? It's not done properly.
How so? Perhaps it is difficult to see the entire set-up in one picture. Technically it's a "homerun" system. The galvanized steel makes up the primary circuit. Off that circuit are three secondaries- the first and second branch points are 10 pipe-diameters from any bends, and the input/outputs are less than 4 pipe diameters from each other. Each is fed by it's own circulator. The third secondary circuit is off a 4-way mixing valve. I installed it the only way I could without causing a chocke-point for the primary circuit.

Quote:
Originally Posted by Splinter View Post
5. Drain valves should be placed on the return of each circuit before it dumps back into the main to purge air out when filling.
OK. I can do this for sure on the 2nd floor circuit, which currently has the drain annd vent on the supply side.

Quote:
Originally Posted by Splinter View Post
6. 150 degree water running through the plates under the first floor hardwood is awfully hot. You're asking for trouble with the hardwood. I know it feels nice on the tootsies, but the floor isnt really supposed to be 85 degrees.
This was the necessary temperature according to the heat-loss calculations (actually 140 degrees). It has to pass through 1.5" of hardwood. That should make the surface temperature of the floor ~75 degrees.

Quote:
Originally Posted by Splinter View Post
7. Put your hand on the circulator, you'll feel the vibration if it's spinning. .
I thought that, but when the primary circuit circulator is moving, I get a slight vibration in the entire system, making this difficult.

I'd rather not start over unless there is a fundemental problem with my set-up.
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Old 12-03-2011, 11:08 AM   #5
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Need help with finishing touches on radiant heat system


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Originally Posted by biggles View Post
why did you use galvinized piping you should of did all copper or black to the headers anyplace you have copper to galvinized with a boiler supplying 170F-180F water you are going to get electrolysis over the coming years you better get some flood insurance...

The black pipe for gas? Doesn't that corrode more than galvanized? anyway, I have dielectric unions anytime there is contact with copper.
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Old 12-03-2011, 11:13 AM   #6
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Need help with finishing touches on radiant heat system


black pipe for commercial installations is an indusrty standard...and definitly residentials from the meters..
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Old 12-03-2011, 11:16 AM   #7
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Need help with finishing touches on radiant heat system


Quote:
Originally Posted by biggles View Post
black pipe for commercial installations is an indusrty standard...and definitly residentials from the meters..

Guess I am confused.... are talking about the same black pipe? The only black pipe in my system supplies gas to the boiler.

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