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proposed HW heating system

steamfitter Member Posts: 156
Thinking about a hw heating system for a friend who may be installing a new system in a ranch house near the shore which was damaged by the storm.

He wants to put the boiler in the attic and downfeed the baseboard in leiu of his old system which used a crawl space for the mains and had the bolier in a utiliy room on the main floor which is roughly 1500 sq. ft. and has three bedrooms, a living rm, dining rm and one bathroom.

I was wondering if I could run a hw heating system using two- one pipe circuits that twined the returns together when it got back in the attic. In other words, run two supplys downfeeding from the boiler in the attic and wrapping around the one-level ranch with two loops and then back up into the attic where they would twin together in a common return to the boiler.

I was considering using TRV's in each room with a by-pass (one size smaller) around the fintube) for controlling the temperature in the rooms while maintaining flow.

One circulator, on the supply (pumping away) and two flow control valves(one per circuit) and a reset controller was what I was thinking. Does this plan make sense? Will I be able to balance this system easily? Should I use circuit setters on the returns or should I put the TRVs on the return instead? With the feeder and the comp. tank just before the pump on the supply off the boiler will I be Ok with air removal?

Finally, can a system like this use a Condensing Boiler? The fuel here is natural gas and my friend wants to install an instantaneous hw heater up in the attic as well.

I appreciate any comments and input. This is all in the planning stages right now as he is awaiting decisions on insurance. The home is right off the beach in the Jersey shore area.

Thanks guys!



  • Paul48
    Paul48 Member Posts: 4,469

    Using TRVs on a series loop is not as easy as that. There are 3-way TRVs available, but not an easy find.People here can help with locating them. A mod/con installed with removal in mind, could be removed in 15 minutes. Mod/cons like volume.....proper amount of radiation in every room, and let the mod/con deal with the whole structure.You'll see people describe a zone off their mod/con as 20 ft of baseboard, and they want to know why they are having issues. Just some thoughts to start the ball rolling.
  • steamfitter
    steamfitter Member Posts: 156
    trv's on hw loop?

    In Holohan's book, "How Come," he shows TRV's being used in a hw loop system with a by-pass which is one size smaller. Is this a difficult task with a system that may have, lets say, six rooms? Would it work in maybe just the three bedrooms? Three way TRV's sounds like it might be expensive.
  • jumper
    jumper Member Posts: 2,285
    why series ?

    Why not a supply manifold and separate supply to each baseboard ? You didn't ask but I would also hang a regular (non bladder) expansion tank as high as I can. Evacuate before filling and then only pressurize to the degree necessary. That will probably be less than atmospheric.
  • bob_46
    bob_46 Member Posts: 813

    Why not run two risers side by side down an inside wall to the crawlspace. In the crawl

    run from one riser clockwise around crawl and the other counter-clockwise. Now you have two pipes all the way around one supply the other return. Connect your emitters from

    supply to return with a trv. You now have two pipe reverse return. I would run a third pipe to the crawl for the relief valve. You might consider a safety drain pan and you need to think about freezing temps.

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