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Thermocouple for United States Radiator Corporation boiler with Honeywell gas parts

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binkelman
binkelman Posts: 1
in THE MAIN WALL

Hello out there! I am trying to track down a replacement thermocouple for my very old boiler. The boiler was made by United States Radiator Corporation of Detroit, series 7-11. Many of the parts were made by Minneapolis Honeywell (Aquastat model L-444, Pilotstat model C509, Gas valve type V88A).

Searching for U.S. Radiator gets me virtually nothing (a company of the same name appears to make radiators for cars now.) Honeywell is a bit more promising, with some info coming up for searches regarding their parts.

I took my thermocouple to just about every place in town. The general consensus is that it seems large and meaty for a run of the mill thermocouple. The odd shaped end and female threads also raised eyebrows. An old paper for the pilotstat mentions thermocouple models Q234 and Q235, among others. Thickness of mine is 1/4 inch.

Surely I cannot be the only person in this predicament. Has anybody here had any luck with finding one? Seems it would be a shame to replace the whole boiler over one small part.

IMG_1445[1].JPG IMG_1446[1].JPG IMG_2489[1].JPG IMG_2490[1].JPG IMG_2487[1].JPG

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Posts: 12,763
    edited 7:48PM

    Not a standard thermocouple. hard to find one of those if at all.

    There is/was a thermocouple adaptor that should take the standard Q340A thermocouple and allow you to use it on that male thread. the part number is/was Honeywell 390012C Power Unit Female Adapter. This information is very old and may no longer be available. There was an eBay listing for those adaptors. You can also google the part number and see if you can find them somewhere. Good Luck

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • EdTheHeaterMan
    EdTheHeaterMan Posts: 12,763

    Common practice is to tell you it's time for a new heating system when you have parts that old. But some mechanics may be able to scrap that old gas valve, pilot switch, and pressure regulator setup and, with a few 3/4" pieces of pipe and some fittings, install a new gas valve that has the pilot switch, pressure regulator, and redundant valve all in one modern part. This might be the way to go.

    See the 4 items circled in yellow…. all 4 of those components are built into the modern gas valve and you can remove all the old parts and install one gas valve that will do the job.

    image.png

    Here is what your boiler might look like after the new gas valve is installed.

    image.png

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    HVACNUT
  • HVACNUT
    HVACNUT Posts: 7,704

    Agree with Ed. Modernize the gas train and pilot assembly if you're not going to upgrade the whole system. If you're going that far and want to feel a little safer, I'd MacGyver a Rollout switch between the burners and install a Spill switch on the bell.

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