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heating set up questions

Osborn Member Posts: 31
I am a homeowner using a TT solo 175 to heat four apartments. The heat loss for each apt is about 25k.  I am planning to distribute the heat with large (10 to 18 section, 25" high) cast iron rads    Each apt has two zones, with two rads each, plus a small piece of baseboard in the baths.   I am planning to use a taco 007 pump for each zone and a taco 0010 for the domestic (a htp 60 gallon).

A few questions:

My rads are oversized, which I'm hoping will allow me to operate the system at a lower temp.  My installer is concerned that the boiler will have problem bringing and maintaining tempurature.  Any issue here??

The longest rad is about 25 vertical and 60 horizontal feet from the boiler.  Is the taco 007 a good choice?

Should the feed on the rads enter at the top of the rad?   They have plugs on each end now.  (Sawzall, drill and screwdriver to get those plugs out.)

Any other feedback appreciated...


  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited March 2011

    Why did you choose a boiler that is 175,000 for a 100,000 btu heat loss? Did you add the domestic to the load? You have a very oversized boiler...

    Boiler will make the water temp that is needed to overcome the heat loss at design. That water temp is going to be dictated by your heat loss and capable emitter output based on conversion from sqft of EDR to btu's.

    Are those radiators 4 Tube or 6 Tube. As an example..These come from slenderized rads currently sold. If you have old column radiators they would not have the same numbers. You would have to calculate their EDR.

    4 Tube 25 High 10 Section Sqft EDR is 20

    6 Tube 25 High 10 Section Sqft EDR is 30

    Big difference in btu output. If the room heat loss is 3000 btu's.

    4 Tube with 180 degree water would put out 3400

    6 Tube with 150 degree water would put out 3300

    Cast iron rads and condensing boilers are perfect partners. I also wouldn't be zoning with all circs.  If I'm paying the fuel dollars each apartment would be on a manifold, pex to rads, thermostatic valves and a Grundfoss Alpha or similar ecm pump and let if fly on the boilers outdoor reset curve. Keep in mind you are also paying for the electricity and they Alpha will pay for itself.

    Lastly, please get rid of the baseboard. It will hurt you in the design and they don't play well together with cast iron rads.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Osborn
    Osborn Member Posts: 31
    heating set up...

    The boiler output is 134000btu.  There's a small "house" zone in addition to the apts and domestic, so the actual demand is a bit higher. 

    Any feedback on the hot water-in location on the rads?

    How would a piece of cast iron baseboard work in those baths (heat loss is 500)?

    The rads are 5 tube so a 10 tube at 150 would give me about 2700 btu or so -  

    Do people have problems with valves sticking?  The zone valves are more efficient than pumps?   You're talking about one manifold for 9 zones.  Can you point me to a product?

    Thanks so much.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited March 2011
    Boiler Size

    Boiler modulates 50-175,000. Might be able to use this if they were single pipe steam and being converted to hot water.


    Piping would be similar to this. Notice I said similar.

    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • VictoriaEnergy
    VictoriaEnergy Member Posts: 126
    hot water piping through rads

    It's standard to have supply and return piping from the bottom connections for rads running hot water.

    I agree the baseboard is a poor choice for the bathrooms.  They are intended to operate at higher water temps than you hope to be running in a ODR/rad system.  You want your bathrooms to be well heated, perhaps doubly so in the case of a rental where the tenant might not be as concerned about mold and rot as they should be if the bathroom stays damp.  Maybe you should try and pick up some small used rads.

    Home Owners Please Note:

    You are receiving advice from some very skilled pros completely free of charge. One of the reasons I participate is to sharpen my own troubleshooting skills. So; did we get it right? I would be grateful if you extend this courtesy back by posting the final outcome of the issue you are inquiring about. Thanks
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