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adding a zone valve and second thermostat

jeff3176
jeff3176 Member Posts: 8
Hello. I have a hot water heat system with 2 pumps. One pump is for the main floor and the other for the basement. Each pump has a Honeywell 832A transformer with one thermostat on each one. My question is this. Can I install a zone valve and a new thermostat to the main floor 832A, or does each thermostat need its own transformer? Does the second thermostat go to the X X terminals and the pump runs, but the boiler doesn't fire? Thanks in advance for any help!

Comments

  • mattmia2
    mattmia2 Member Posts: 7,207
    What are you trying to do? Split the main floor in to 2 zones? Add new second zone to the main floor?

    The general gist is that if you are zoning with zone valves the thermostat controls the zone valve and the end switches on the zone valves control the circulator and the boiler(in your case I think an aux contact on the circulator relay controls the boiler).

    You will need to make sure that the circulator and the boiler are ok with the size of the smallest zone being the only load on the system. If it is a cast iron boiler then this isn't an issue with the boiler but in somewhat rare cases could be an issue with the circulator. It can be an issue with more modern types of boilers.

    You will need to look at the load of the controls you are adding and the output of the transformer to determine how many zone valves and relays you can put on one transformer.
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,511
    edited July 2022
    Yes, you can do that, but when the new zone calls for heat, both zones will get hot whether or not the existing zone is calling for heat.

    In order to make each zone independent, you will have to install zone valves on each zone or add a second pump for the new zone.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour2 btu/ per sq ft for degree difference for a slab
  • HomerJSmith
    HomerJSmith Member Posts: 1,927
    edited July 2022
    What you are saying, I think is that each pump has a switching relay. The switching relay does have an internal transformer.

    Can I install a zone valve and a new thermostat to the main floor 832A, or does each thermostat need its own transformer?


    Depends on what you want to accomplish. Give me a scenario of what you want to do.

    Thermostats don't need a separate transformer, necessarily. It depends on the current draw. Pumps do need a way for the thermostat to turn the pumps on, tho, and for the boiler to turn on, too. That's what a switching relay does.






  • jeff3176
    jeff3176 Member Posts: 8
    Here's what I want to accomplish. The main floor loop used to have zone valves in every room and each room in turn had their own thermostat. I now want to keep one room cooler than the rest of the main floor. Maybe instead of a zone valves and thermostats, I should install a ball valve and restrict the flow to that room??? Thanks again!
  • hot_rod
    hot_rod Member Posts: 18,265
    Do you have fin tube baseboard heat? If so you can close off or regulate the damper to slow heat output

    or cover some fins with aluminum foil if there are no dampers

    wuth radiant floor heat, you may be able to balance flow down.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • mattmia2
    mattmia2 Member Posts: 7,207
    Are the emitters in series or parallel? It sounds like they are in parallel unless the removal of t-stats included repiping.

    If they are parallel this is the perfect application for a TRV.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,991
    edited July 2022
    @jeff3176 said:

    With comments in italic by @EdTheHeaterMan

    Hello. I have a hot water heat system with 2 pumps. One pump is for the main floor and the other for the basement. Each pump has a Honeywell 832A transformer with one thermostat on each one. My question is this. Can I install a zone valve and a new thermostat to the main floor 832A, or does each thermostat need its own transformer? Does the second thermostat go to the X X terminals. the answer to this is NO and the pump runs, but the boiler doesn't fire? Thanks in advance for any help!

    Here's what I want to accomplish. The main floor loop used to have zone valves Are they still there? in every room and each room in turn had their own thermostat. I now want to keep one room cooler than the rest of the main floor. Maybe instead of a zone valves and thermostats, I should install a ball valve and restrict the flow to that room???. This will not be vert accurate in controlling temperature Thanks again!

    More information is needed:

    How are the pipes to each room radiator connected to the man pipe(s) on the first floor circuit?
    Possible answers are
    1. Series loop
    2. Reverse return
    3. Parallel return (or ladder type design)
    4. Monoflo (or one pipe diverter tee design)
    5. Old converted gravity piping design
    6. Other ???

    What type radiators are in your home?
    Possible answers are:
    1. Copper tube aluminum fin baseboard
    2. Cast iron baseboard
    3. Cast iron standing radiators
    4. European style panel radiators
    5. Convector radiators (sometimes inserted in the wall) with a cabinet enclosure
    6. Other ???

    If the zone valves are still there, are they motorized electrical operated valves or are they non electric thermostatic radiator valves?
    1. What brand
    2. What model number
    3. (a picture will be enough)

    With this information the solution will be easier to determine.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • jeff3176
    jeff3176 Member Posts: 8
    The zone valves were of the mechanical type. (house was built in the early '60's) All the heaters are copper tube aluminum fin baseboard type. The main loop is 1.25" copper, and the baseboards are teed off to .75". I realize a ball valve isn't as accurate as a thermostat, but was just thinking it was much simpler.