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old Mansion heating renovation help

GW Member Posts: 4,700
Hi Guys,

I’m looking at this job where I could use some help. The existing system is original hot water gravity. Only the boilers seem modernized, and they seem to be a good 40-50 years old. The system is a combination of radiators and heat exchanger units that bring in fresh air from outside. He’s looking for 3 prices; I told him I’d give him some rough ideas on price and then take it to the next level with some design work.

I’m hoping there’s a mansion heating guy out there who might be able to push me in the right direction. He’s interested in 3 prices.

One- to redo the boilers. They’re gas, about 900,000 btu between the two. If I replace, is it crazy to stick with gravity? I’m not sure what’s up with the rads though; with my luck they’ll all be restricted with orifices. Would the HX units be fine with water being pumped through them? I can’t see why not, but on a job of this scale I’d prefer not to assume!

Two- redo the entire heating system. I’m thinking about using the same ducts that are there now, get rid of the fresh air intakes, install a bunch of oversized AHUs with a low blower speed, get some return air installed (OK, a lot of return air installed). It won’t be perfect but better than what he has now.

Three- add AC. If we do this I will install mini-duct; probably a couple of boilers and a couple of chillers.

Thanks for any help!

Gary Wilson
Wilson Services, Inc
Northampton, MA


  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    mansion restoration

    I've renovated a fair share of mansions...take a look at the Meeker Mansion restoration on my website.

    I'd be looking at a staged or modulating boiler system using either a Viessmann Vertomat boiler or (2) Vitogas GS10 series boilers staged with the lead-lag control and Vitotronic 200. I'd use a 4 way mixing valve to protect the boiler(s) from thermal shock, or a 3 way, if the Vertomat is used.

    The A/C spec is a matter of the existing ductwork...is it in good shape, or toast. The mini-duct (HV) systems are easier to install in older buildings.

    Make sure to do a connected load EDR heatloss and add for friction losses. Viessmann can help with the boiler design and schematics, if you haven't used them before. They have a commercial software package that can show "break-even" costs and fuel cost analysis. Contact your local Viessmann rep.

    I'd recommend revalving all of the cast iron radiator valves with TRV's

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  • Brian Tober
    Brian Tober Member Posts: 18

    What brand of TRV's do you use and how much do they cost approx? 3/4 npt size.
  • c.t.kay
    c.t.kay Member Posts: 85

    try tundstall associates/macon controls. www.tunstall-inc.com , or call 413 594 8695.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656

    I use both Danfoss and Oventrop, depending upon the type or head required. Oventrop makes specialty heads and valve bodies in colors and both chrome and satin finishes.

    The more I buy, the less they cost... I've found Chris Rorke at Bluline Supply in Jackson Hole, WY. to be the best source in the states. At least out West! Eastern sources may be easier to find. The Canadians are well served by Danfoss in CA. THE NW, for some reason, has less hydronic goodies available.

    He'll gladly quote a project, or basic stock. He ships UPS and never misses a beat.

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