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Temporary Heat


Doing a major remodel and just poured my downstairs slab with my pex loops. I'd like to pump some heat into it this winter while we work on the rest of the house, and complete the total heating system next summer. My thought was to set up a cheap plate heat exchanger from ebay and hook it to my old hot water tank with a couple of pumps and temp. sensors to keep the downstairs space somewhat warm. I'd like to select pumps that could be repurposed into the final system and most likely just monitor loop temps to keep it warm. I have plenty of 3/4 copper that I can repurpose to pumb it up. In Zone 4, Seattle area.

1,200 sqft area with 6 loops 1/2" hePEX on a uponor EP manifold, approx 1,125 ft of tubing. Slab is insulated with R-10 xps underneath and on the parameter. Load calcs came in around 12,000 btu/hr for final system but of course, losses will be much greater due to being under construction. Current water heater is 50gal 38,000 btu, natural gas model. Only two of us in the house so we don't use much hot water, and was considering turning off the pumps if I could sense when we had dhw flow. Just need to run it for about 4 months.

Do you guys think this is this possible, and any ideas on pumps and sensors?

- Ron


  • hot_rod
    hot_rod Member Posts: 19,933
    Sure, you need a stainless circ on the water heater side. needs to be lead free on the potable side nowadays. One or both circs could start by a thermostat.
    The used to be a few companies that built a Water Heater radiant module, a pump and HX for that application, not sure if they are still offered.
    Taco has a Radiant HX Mix block, maybe more features than you need but a simple plug and play.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • NWOtter
    NWOtter Member Posts: 2
    Thanks! I checked out the Mix block, cool unit but spendy. I think I want to be a little more "discreet" with my design so that it's a less expensive to service. I'm getting the components together and will look to add some control after I have it plumbed up.

    I'm sure I'll be posting more as I get more time to work on my permanent system.

    - Ron