HX INSTALL ?

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mmfan36

Member
Hearth Supporter
Jun 4, 2008
19
north jersey
MY CIRCULATOR PUMPS ARE ON THE RETURN SIDE OF MY BOILER.WHEN I ADD THE PUMP TO PUSH THE WATER THROUGH THE HX IN TO THE BOILER.IS THIS GOING TO HURT THE OTHER RETURN PUMPS.THANKS KEVIN
 
I think the answer is "no," but post a diagram to help us understand what your system looks like.
 
In the configurations I've seen with no storage, the hx goes right in the return side of the existing system so that the cold return water passes through the hx prior to reentering the existing boiler. In that case, it's the existing circulators that push the water through the hx and there is no "added" pump. Jim's suggestion for a diagram will help...maybe your setup needs a different approach.
 
Interior Alaska
I have the EKO-60 hooked up and running, supplying hot water to two 500 gal. propane tanks. Just prior to the entrance to the propane tanks, I teed off the supply(hot) and return (cool) lines to these tanks and feed a flat plate heat exchanger. From the heat exchanger I supply hot (glycol) to the inlet pump on the oil fired boiler. Just upstream of this connection at the oil fired boiler return water inlet, I have another tee for the return (cooler glycol) to the heat exchanger. When a thermostat in a room calls for heat and the zone valve opens, the circulator on the oil boiler go and feed the zone. I have connected additional wires from this circ pump to the 2 circ pumps on each side of the heat exchanger. I ran power to these heat exchanger circ pumps through a honeywell L6006 aquastat set at 80(f) so that the tanks need to be at least 80(f) of the heat exchanger circ pumps get no power. > 80(f) and the HX circ pumps get power if the oil boiler circ pump is running.
I measured the water temp flowing into the inlet side of the circ pump at the oil boiler and it is pretty close to the water temp in the 2 storage tanks. Still the oil boiler runs unless I set the honeywell L7124 aquastat on the oil boiler to 120 low and 140 high. Normally it is set at 180 low 200 high as it has an internal tankless heater.
I am trying to keep the oil boiler system pretty much intact so that it can take over whenever the EKO is shutdown and the water in the storage tanks has cooled off. .
I have three zone, 2 of which are radiat floor heat so I can heat with lower water temp. One zone is upstair and is baseboard heat, however I can get by with lower water temp to that zone as well since it is a bedroom and cooler is better.
Enclosed is a picture of the two 1-1/4" pipes that go from HX to inlet side of Oil boiler. There is a circ pump that pushed hot glycol from the HX into the TEE by the inlet side of the oil boiiler. When the zone calls for heat, all the circ pumps go, if and only if the storage tanks are above 80(f). It works OK.
 

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Here are the pics of the 1-1/4" pipes that run from HX to inlet side of oil boiler
 

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Here are some pics out in the shed where the two tanks live and the heat exchanger lives.
 

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If your question still is whether there is any harm to the oil circ pump in having the circ pump from the hx pushing water through the "off" circ pump on the oil boiler, I believe the answer is "no."

If you have other questions, go ahead and ask, as based on your description and diagram, I think you probably have provided enough info now to address questions.

How's the EKO and storage working for you? Is the oil boiler on true stand-by? How often is it firing?
 
On my set up the oil boiler is not "true standby " UNLESS I turn the low temp setting on the aquastat to "disable". Then ALL the circ pump operate when a zone calls for heat and the oil boiler never fires.
I did this for testing and it all works fine since I have radiant floor heat, I don't need such hot water. Even with the current setup , the oil boiler rarely runs and if the tanks are up to 180, the oil boiler runs briefly and then shuts off as soon as that hot glycol from the HX feeds into the oil boiiler.
I have a SuperStor Ultra 45 but need to install it. Its the next project.

Next summer, I may add a valve and a couple of tees and try running both boilers in parallel.
The storage tanks work fine. They are side by side, with 1-1/2" pipe feeding supply and return. They stratify equally and after a few hours, are pretty much even top to bottom. I think this is mainly due to all the insulation I have in place. Even with those tanks insulated, the 16x16 storage room stay 75(f) when out side it it 9(f) and the tanks are 170-180 (f) so even more insulation and taping of the seams may help. A 1000 gallons of 180(f) is a tremendous amount of energy.....
 
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