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Combi boiler in series with tank?

I curreny have two 50 gallon electric tank water heaters plumbed in series. I have a separate 199k btu combi boiler that is currently only being used for radiant heat floors. I'm considering getting rid of one tank heater and plumbing the combi boiler in series with the remaining tank heater. So cold water goes into the boiler, its heated and flows into the tank heater. My assumption is I'd have instant hot water and unlimited hot water. I also have a hot water recirculator that pumps recirculated water into the bottom of the tank heater.

My main questions:
1. Are there any issues with plumbing a combi boiler in series with a tank water heater? If I wire the combi boiler in series do I still have my recirulator pump dump into the boiler?


  • kcopp
    kcopp Member Posts: 4,448
    I have done the combi in series w/ an electric tank.
    If you do the recirc line I would not pump it through the boiler. Use the tank to do this.