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CSD-1 Code

ToddD Member Posts: 1
In the state of Massachusetts; commercial application, when is CSD-1 code required. 750,000 BTU pool heater being installed.

Are high and low gas pressure switches required?

Is a factory "authorized" start up required?


  • Tim McElwain
    Tim McElwain Member Posts: 4,628
    Is the pool heater being installed

    in a building with public access? If it is then CSD-1 applies. It is over 400,000 so that also is applicable. For Mass go to 522 CMR Board of Boiler Rules "Controls and safety devices for automatically fired boilers (ASME Safety Code, NO. CSD-1, Part CW Steam and waterside controls , 1977) Units over 200,000 BTU's. Most of that has to do with LWCO's and Flow Controls. There is no mention of High and Low gas pressure switches. I would check with local gas inspector on that however.

    I would also get a ruling from your local gas inspector concerning pool heaters in general as installed in public building if that is in fact what you have..

    What is the make of pool heater? Do they make any provision in the I and O manual for CSD-1 applications? If not you may have to contact them.
  • furnacefigher15
    furnacefigher15 Member Posts: 514

    ASME Standard CSD-1

    The state of Mass may be more strict. But here is portion of CSD-1 that applies

    burners between 400,000 and 2.5 million btu

    For Power or mechanical draft burners You need:

    On direct fired you need high and low gas psi safeties

    on pilot fired you don't

    You need two automatic gas valves in series (with a vent valve between) or one valve that has a proof of closure interlock switch.

    Also, proof of combustion air is required.

    For atmospheric draft, no pressure safeties are needed, and only 1 automatic gas valve is required.

    In either case, 5 sec main valve closing time required.

    You are also required to have both an operating temperature limit, and a manual reset high limit.

    You are also required to have a LWCO, 2 main line manual gas shut off valves (1 before the regulator, and another between the final gas valve and the burner)

    If the boiler is modular, with 2 separate combustion chambers below 400,000 btu, then

    no gas psi safeties are needed in any case, and only one manual shut off is needed.
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