for you experienced HVAC guys, please help me with this idea.
I have a HW radiator system that is 1 zone. a single feed loop in the basement runs the perimeter of the house, feeding 5 radiators on the 1st floor and 3 radiators on the 2nd floor. a new hi-eff boiler was installed 7 years ago. each radiator branch has a one way flow check valve on one leg of each 2 leg (in-out) branch. the house is a Cape style with an open stairwell. since the heat always rises, I wanted to create a separate zone for upstairs, so it would call for heat only on demand. I’m thinking this would put more hot water on the 1st floor which is always cooler than the 2nd.
so I’m thinking instead of piping an entire 2nd feed loop, I could install solenoid valves on the 2nd floor branches, wired to an upstairs thermostat. this would cut off water supply when not needed and open when it was.
question: with the 2nd floor shut off for a period, will there be a problem with the introduction of coooler water back into the loop when the valves open. will the recovery of the system be too long, negating any savings of redirected hot water?
Thanks.
Replies
TRV's. That stands for "thermostatic radiator valves". This is the easiest and probably best way to zone a radiator based system. Leave all the downstairs units alone, and put TRV's on the units upstairs. I would be quite suprized if the house has absolutely no zoning whatsoever. Is this something that you know enough about to recognize the controls that are in place? "A new hi-eff boiler was installed 7 years ago..." how long have you lived there? How well did the system work before that work was done?
"question: with the 2nd floor shut off for a period, will there be a problem with the introduction of coooler water back into the loop when the valves open." No. If it hasn't been a problem in the past, it probably won't be a problem now. Older style, non-condesing boilers are installed (piped) in a manner that protects the boiler from cold water returns during startups and warmup. Newer condensing style boilers can take room temperature water without harm.
"will the recovery of the system be too long, negating any savings of redirected hot water?" No, though I would not expect significant savings.