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Multiple Boilers/3 Separate Headers/1 Common

I am working on a building with 3 existing boilers, each of which has an individual supply & return header feeding multiple zones through out the building. The boilers feed baseboard radiators and control is obtained through 2 way valves on the supply header (each header has approx. 5 zones, each tied to an individual thermostat). We have added a heat pump system for air conditioning and would like to supplement the radiant heat with the heat pumps. This will be accomplished by installing a heat exchanger between the heat pump loop and the boiler loop. My question is how do I tie in the 3 separate boilers into some sort of common header, have each boiler contribute heat equally, and still maintain the integrity of the remaining boiler system? As is, the boilers are all operating at different times when the call for heat arises. We would like them to all fire in unison when the heat pump loop calls for heat. Our scope of work does not involve any reconfiguration of the existing zones, so we need leave all existing zoning as is. Any ideas would be greatly appreciated!

Comments

  • Waylon Lowery
    Waylon Lowery Member Posts: 57
    It sounds like you will need to

    tear out the existing piping and start over.

    If I were you, I would use each boiler and its associated pump to pump into a primary loop with a primary loop pump. Note: Use reverse return on the boilers. Then I would install three circulators off of the primary loop that would feed your three different areas of baseboard. I would use an injection pump piped off of your primary loop to inject water into your heat pump loop (Your Heat Pump Loop will require miniscule amounts of hot water to keep it near its setpoint). Then I would use a Tekmar boiler sequencer to control the boilers and their boiler pumps. The Tekmar would sequence, stage, and rotate the boilers to match the load and maximize efficiency. E-mail me if you need more help....
  • Weezbo
    Weezbo Member Posts: 6,232
    waylons idea is better than having them all firing at the ....

    same time. each one will stage in the caravan and every 50 hrs of run time or so the lag will be the lead and the next go round the lag will be the lead that way when your boilers kick in only sufficent heat will be generated into the system at any given demand at any given momment...the piping arrangement will keep temps up a bit on the return and that helps protect the boilers.i do not know much about heat pumps...
  • GEO_3
    GEO_3 Member Posts: 67
    heat pump?

    What kind of suplemental heat are you planning to get out of a heat pump? or is that going to be the primary with the boilers suplementing?
This discussion has been closed.