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Re: wiring boiler/ergomax in my situation

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Posted by HeatPro on February 05, 2006 at 04:19:18:

In Reply to: wiring boiler/ergomax in my situation posted by Dave on February 05, 2006 at 00:37:28:

: Well, we piped in the ergomax into my system and had 1 problem. The Taco 0010 was actually pumping boiler water through all our supply pumps in the header even when the pumps were not running so that all zones were very hot at all times.
+++ This was the problem you needed to solve before doing anything else. As the supply to the supply manifold for the zones is off the boiler supply/tank tee, and the house return is at the boiler return/tank tee - there is enough resistance in the tank that is providing the force to send water through the circuits over the resistance of the flow controls. Closing down a balancing valve in each of the circuits more than likely would have stopped the excess flow without requiring changes. It is not always necessary to change parts, wiring strategies and circuits to 'tune' a system.
The idea: http://www.victaulic.com/docs/lit/08.16.pdf

See balancing valve here:

: I spoke with Adam at Ergomax/Group Thermal and he recommended repiping as follows:
: We kept the primary/boiler loop the same (boiler water enters top of Ergomax and water returns to boiler from bottom of ergomax through 0010 pump that pumps into boiler).
: Adam told us to put supply and return headers as 2 closely spaced tees off the return from ergomax to boiler which we did about 3 feet from tank.
: We found that 0010 pump must now run whenever any zone is calling for heat, as individual pumps will not pull hot water into zones unless boiler pump is operating.
+++ Yes, this was the reason for the change of the household circuits return header from the upper manifold as it was originally. Adam hasn't followed the progression through this design for a year, it was new to him. Now you have the same situation as when the manifolds were on the upper piping before doing anything with the same problems as you list below.

: This creates the following problems:
: 1. When I had ergomax alone wired across TT on boiler, we had the situation where the tank called for heat after our other zone pumps had shut down and boiler locked out as there was no boiler pump running. (boiler pump was wired through Taco SR504 to run only when individual pumps were running).
+++ That was a mistake. The boiler pump should have been left as it was to run when the burner was on from the original boiler wiring as gone over carefully in many emails previously, not to the SR504.

: 2. I removed ergomax aquastat connections on boiler and wired the TT terminals on boiler to endswitch on Taco SR504. So any zone could call for heat from boiler. However, if the system was idle for a while so that boiler cooled down and then a zone called for heat, even though ergomax was 160 degrees, the boiler immediately started because the water in it was cold.
+++ the HeatManager would have prevented that. So you created a problem from not completing the job before fixing something that would have gone away.

Boiler operating temp is 175 and high fire is 160. So if boiler had cooled down substantially and then a zone called for heat, boiler pump would come on as inlet temp was about 120 and boiler would fire even though relatively quickly it was seeing 150 degree water flowing through it.
: What would be the best way to make this situation more efficient?
+++ Pipe it the way it was and finish the job by metering the circuit flow with balancing valves. Stick to the original wiring and piping plan until completed, tune it to work properly and don't create more problems by not finish-tuning it for definite circuit resistances due to temperature drop with the circuit pump running.

I would like boiler to be controlled by aquastat from ergomax only. And the boiler pump needs to run when either boiler calls for heat, or any individual zone runs.
: I am not against getting rid of SR 504 if something else would work better.
: I was thinking....would it be possible to treat the aquastat on the ergomax as a thermostat input on the SR504, then I would add another low voltage wire that goes parallel from the ergomax input on the SR504 to TT on the boiler? Then, the ergomax would run the boiler pump whenever it called for heat as well as fire the boiler and also the zone pumps would also run the boiler pump as needed?
+++ You can continue to create problems, then add as many controls as will fit in the building before settling for a good design.

: Would heatmanager work well also in this situation?
+++It would work in the original configuration better; but in whatever situation you change it to daily, it will prevent the boiler from firing too frequently.

The only problems you had were from not setting the circuit flow resistances and from inventing the wiring of the boiler pump to the SR504.

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