Non-condensing Boiler Pumping with 3-way Valve
Non-condensing Boiler Pumping with 3-way Valve
(OP)
Gents,
I have come across a boiler piping arrangements last week where I can only identify one set of pumps, and what seems to be a primary secondary system decoupled by a 3-way valve. I'm used to seeing this arrangement with two separate sets of pumps, one set of the primary loop, and one set of the secondary. The latest work was done in the 70's. I am tasked with removing these older boilers, and replacing with low mass condensing boilers. Does anyone have experience with this type of piping arrangement? Thanks.
Picture attached
I have come across a boiler piping arrangements last week where I can only identify one set of pumps, and what seems to be a primary secondary system decoupled by a 3-way valve. I'm used to seeing this arrangement with two separate sets of pumps, one set of the primary loop, and one set of the secondary. The latest work was done in the 70's. I am tasked with removing these older boilers, and replacing with low mass condensing boilers. Does anyone have experience with this type of piping arrangement? Thanks.
Picture attached





RE: Non-condensing Boiler Pumping with 3-way Valve
A diagram would be a lot better.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Non-condensing Boiler Pumping with 3-way Valve
RE: Non-condensing Boiler Pumping with 3-way Valve
I'm aware of the relationship between return temp and condensing boiler efficiency. I just want to make sure I understand the system as it currently stands. I've only seen primary secondary in older boiler systems, not this three-way arrangement.
RE: Non-condensing Boiler Pumping with 3-way Valve
Your new CONDENSING boiler has a stainless steel or aluminum heat exchanger and benefits from condensation (hence the name condensing boiler). condensation is what you want, you want return temp as low as possible. So this valve would defeat he purpose of a condensing boiler.
RE: Non-condensing Boiler Pumping with 3-way Valve
I wasn't pointing out return temp as being a function of condensing, I was pointing it out as the affect it will have on the downstream items, coils, unit heaters, etc. If they are designed around a 20 degree delta at 200 EWT, but you need them to be at a 60 degree delta, they wont function properly. To maximize your condensing boiler you need return water temps in the 120s, which is quite a ways from the 160 you are at.
RE: Non-condensing Boiler Pumping with 3-way Valve
RE: Non-condensing Boiler Pumping with 3-way Valve
I've seen many copper finned tube boilers on much smaller applications need this.
RE: Non-condensing Boiler Pumping with 3-way Valve
You design your new boiler to serve existing consumers on secondary, not to serve piping