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Inexpensive Aquastat

Zman
Zman Member Posts: 7,611
in THE MAIN WALL
I am looking to change the controlling of 14 garage hydronic unit heaters. I want to make the fans operate only when the boiler is firing. I could use a typical strap on aquastat with full range of adjustment, this option is getting expensive. I have seen fixed temp strap on switches on kickspace heaters and even a few boilers. These look very similar to HVAC "snap disc "controls. I will be running line voltage so a protective box will be necessary.

Thank you for your input.
"If you can't explain it simply, you don't understand it well enough"
Albert Einstein

Comments

  • SWEI
    SWEI Member Posts: 7,356
    Help me understand this...

    You want to install 14 aquastats, each controlling one fan - or you want to control the power to all 14 fans with one aquastat?
  • Steamhead
    Steamhead Member Posts: 17,387
    I think

    by the time you put together a snap-disc inside a box of some sort that could protect and properly ground the 120-volt wiring, the extra labor would cancel out any savings. Go with the Honeywell or White-Rodgers strap-ons, they're designed for this use. Sometimes you can get a better price on one brand or the other, depending on the suppliers you use. 
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Zman
    Zman Member Posts: 7,611
    14

    SWEI, Yes 14 aquastats. The units are about 50 feet apart.

    Steamhead, You are probably right. It is one of those products that I have seen as an OEM part, but never at a supply house.

    Thanks

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    edited March 2012
    Try W.W. Graingers....

    They have snap discs of every reasonable range, for a fairly inexpensive cost.



    http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=bi-metal+snap+discs&withinSearch.x=0&withinSearch.y=0&op=search&Ntt=bi-metal+snap+discs&sst=All&N=14913





    How do you intend to limit the garage room temperature?





    ME

    There was an error rendering this rich post.

  • Zman
    Zman Member Posts: 7,611
    Thanks ME

    Mark,

    Those look perfect. Any ideas on protecting the line voltage wiring?

    Presently the garage boiler is always on and always circulating through the coils for the entire heating season. The fan coils have individual thermostats which are initially set around 50 degrees. Over the course of the season the residents seem to "adjust" them individually. Yesterday the garage averaged 60 degrees.

    My plan is to wire the aquastat in series with the existing thermostat in order to give some local control. I was thinking about using one or two tekmar 150 setpoint controllers mounted in the boiler room with remote sensors in the center of the garage. Additionally I plan on using a tekmar 261 to do a slight outdoor reset (noncondensing boiler) and to set the WWSD feature quite low.

    I am a little concerned about condensing the boiler on startup. It is piped primary/secondary and has signifacant system volume. The Boiler is an older copper fin with fairly low mass. The heating loop is hundreds of feet of 2" to 3" pipe. I had thought about controlling the system pump with an aquastat on the boiler, making it run only when the boiler is up to temp. I suspect this stategy will make the system pump surge on and off. Perhaps an aquastat with a wide differential will help with this?

    Thoughts?

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Paul48
    Paul48 Member Posts: 4,469
    Alternative?

    http://www.comfort-calc.net/Piping/P-S_ESBS_Valve.jpg
This discussion has been closed.

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