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Ken_8Ken_8 Member Posts: 1,640
Replacement heating and cooling system at a four story office building.

The present system is a steam boiler with steam to water HX. The water side is pumped into multiple (around 20) 2 to 3 ton heat pumps located in each office area ceiling.

There's a cooling tower on the roof for the summer A/C functioning of the inside heat pumps.

I know condensing boilers love cool return water temps. I wonder how they'll like a 65 degree return water temp and a 75 degree supply water temp?

Think that sucker will condense?

My A/C wizard has the summer side, cooling tower and heat pump ends all covered. The boiler room is mine. Other than simple bypassing arrangement to get into a more comfortable water temperature range for the condensing boilers contemplated, how low do you suppose a condensing boiler can go without going "too low" in system water temps?

I should and will contact all the manufacturers but thought many of you might know off the top of your head.

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  • EarthfireEarthfire Member Posts: 543
    Boiler temps

    sounds to me that a primary secondary pumping system with variable speed on the secondary pumps would keep your temps at low enough levels for the heatpumps, while letting the boilers run at their own sweet spot
  • Mark Eatherton1Mark Eatherton1 Member Posts: 2,542
    I'm not sure...

    there IS a bottom end to these babies. I know they're used on snowmelt systems that have fluids coming back below freezing for quite some time...

    HTP now has a 399,000 btuH boiler available in the Munchkin line. I'd suggest you call Mr. Brian French at HTP and get his opinion. I know you're a W/Mc kind of guy, but you might want to consider the number of boilers you'd need for this application. I think Patterson Kelly just brought their aluminum block condensor to the market, and I know Teledyne has something on the market too.

    Let us know what you do find.

  • EarthfireEarthfire Member Posts: 543

    Are you forgetting about the Ultra?
  • Mark Eatherton1Mark Eatherton1 Member Posts: 2,542
    I didn't realize

    their range had increased. When I first saw them, they were low end only. I see they now have a BIGGER model. Could also be my tunnel vision...:-)

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