TT installed but questions remain


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Old 11-18-10, 07:30 AM
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TT installed but questions remain

http://i1119.photobucket.com/albums/...g?t=1290092663

This is TT prestige 110 with Solo IDWH. It's direct piping on single zone. Both the house heating and water heater seem to work fine so far.

Does the return piping the way it is joined look ok? There is one check valve on the heating return side but none on the DWH return. Do you think another check valve is needed on DWH side? As far as I can tell, it doesn't seem to cause any recirculation to DWH side when heating is on but I know that the manual recommends one.
 
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Old 11-18-10, 04:21 PM
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Take a close look at your DHW circulator. Chances are it has an integral flow check.
 
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Old 11-18-10, 04:26 PM
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I would like to see a check right after the tank.
These tank in tank indirect can have a tendency to have ghost flow with in the pipe since the supply and return are so big, and there is very little flow restriction in these tanks.

Worst case is that when the heating return water passes the tee, it will pick up heat from the tank. This will add heat to the system and the boiler will not have to work as hard and increase the return water possibly reducing efficiency.
 
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Old 11-18-10, 05:56 PM
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Is that 3/4" pipe? I hope not.
 
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Old 11-18-10, 08:30 PM
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Wet rotor circulator cans (motor) must never be mounted up, look at the instructions, bearing will wear out prematurely.
Is that pump say FC after nomenclature? it may be a check pump.

3/4" heating return? is it a fairly small home?
 
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Old 11-19-10, 05:33 AM
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Originally Posted by TOHeating View Post
I would like to see a check right after the tank.
These tank in tank indirect can have a tendency to have ghost flow with in the pipe since the supply and return are so big, and there is very little flow restriction in these tanks.

Worst case is that when the heating return water passes the tee, it will pick up heat from the tank. This will add heat to the system and the boiler will not have to work as hard and increase the return water possibly reducing efficiency.
The pipe is 1". So the pump is grundfos 15-58 with internal check valve. So yes, there is check valve built in. Do you think that's enough to prevent any ghost flow or gravity flow?

I do agree that the tee can be move further away from the boiler so that DWH loop is more isolated from heating loop.
 
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Old 11-19-10, 05:56 AM
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Originally Posted by ZL700 View Post
Wet rotor circulator cans (motor) must never be mounted up, look at the instructions, bearing will wear out prematurely.
Is that pump say FC after nomenclature? it may be a check pump.

3/4" heating return? is it a fairly small home?
That is a good catch. Only if installers follow instructions on the manual right? The plumber did ok job overall but there are a few details he didn't get right so I'm trying to get him back and fix. This will be one of them.

One other thing that is not clear from this picture is that the water feeder line(including the expansion tank, auto filler etc) is connected to supply line out of the boiler. Does it matter whether it's connected to supply or return line? I see that in the examples from the TT manual have the feeder line usually attached to return line.
 
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Old 11-19-10, 06:28 AM
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You generally want to "pump away" from the expansion tank. In typical through-the-boiler installations, you want the water to flow from the boiler, to the expansion tank connection point, and then to the circulator.

Since you can't do that with the Solo 110 (pump is internal to the boiler), the best compromise is to put the expansion tank just before the boiler (on the return side of the boiler).
 
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Old 11-19-10, 08:56 AM
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Originally Posted by jgalak View Post
You generally want to "pump away" from the expansion tank. In typical through-the-boiler installations, you want the water to flow from the boiler, to the expansion tank connection point, and then to the circulator.

Since you can't do that with the Solo 110 (pump is internal to the boiler), the best compromise is to put the expansion tank just before the boiler (on the return side of the boiler).
Ok, so that's another detail he missed. This one may be a harder one to push through since it requires bigger piping change. How important is it that the expansion tank be 'pulled' from pump? What kind of problem it may cause if it is being pushed by the pump?
 
 

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