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ITT-Low Water Cut, obsolete,

Mx2
Mx2 Member Posts: 3
edited October 28 in Thermostats and Controls

ITT-McDonnell model:51 Boiler water feeders.
We have an Ajax, water tube boiler for hydronic heat in a fan-coil system. The external L.W.C . uses float style cut out with ITT-McDonnell No:2 electric switch. (The feed water part is not used). Best description is a poor man’s secondary-low water loop cutout or what was available in the industry at the time and supplied by Ajax Boilers.

The 51 style are obsolete and bellows assembly (parts) getting difficult to resource. What in the water heating industry is a standard, (external of boiler) boiler water loop fluid loss switch/sensor/device to shut controls equivalent to McDonnalls Model51 function?

Ref:McDonnell & Miller Instruction Manual MM-315E

Thx in advance.

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 18,857

    The #51 is still available its been made for years certainly not obsolete.

    But if your not using the water feeder function then there is no need to pay for it.

    All you need is a low water cutoff.

    Hydrolevel has probe type controls that you can mount external to the boiler, and they make a chamber you mount where the 51 is. You have to search a little in there catalog for the chamber.

    Or you can replace the 51 with a McDonnell Miller #63 which is a float operated control similar to the 51 with no feeder.

    Or you can replace it with a McDonnell Miller probe type electronic control

    Mx2
  • 109A_5
    109A_5 Member Posts: 3,081
    edited October 29

    How many do you need ? It appears supplyhouse.com has 4 and access 4 more.

    BA-51-05, Bellows Assembly for 51 Water Feeder

    https://www.supplyhouse.com/Mcdonnell-Miller-310439-BA-51-05-Bellows-Assembly-for-51-Water-Feeder

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    Mx2
  • Mx2
    Mx2 Member Posts: 3

    EBEBRAT & 109A-5,

    Thank you for your response. Exact info we’re looking for. I had already ordered one baffle as I had my suspicions on that. Also: #51 is obsolete per McDonnell etc. and I think #63 our facility Eng. stated not rated for press and or temp(?) Eng initially stated bellows limited availability but this morning he noted as you, 4 at supply house and common item. Now that the 4 boilers are hot -3 bellows are leaking (dripping out of forward housing. so he’s resourcing 3 or 4 . It’s a complicated process to shut boilers down in our facilities, not impossible and the leaks are not gross, manageable possibly till spring. They just came out of the summer outage and service as I find facility operators noted no issues in the official non-existent log book. And no body said anything because it’s not their job. (How to say gov. without saying just that.) So, now I go back to the shop and wait for spring when boilers are shut down to make repairs or they figure it all out.

    Also thanks for the complete cut out replacement info. I will chase that down.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 18,857

    Are these low-pressure steam boilers 15psi max?

    There are so many 1000s of MM 51 feeders installed they have been made for probably 80 years I seriously doubt that while some may consider the design obsolete that MM is going to stop making these controls. They make a fortune selling these.

    As far as the #63 goes it is rated for up to 50psi boiler pressure and the #51 is rated for 35psi so I think your engineer is off base

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