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Boiler is old but it is (was) reliable

Amaster Member Posts: 1
My parents have a National-US Radiator Boiler no. 6-11B which is not heating up for the last two months. It has served well. I think the relay switch has gone bad but I cannot seem to know what is the Part Number or the make. Pictures of these are attached. Any help in this matter would be appreciated.


  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,113
    Baso switch?  Mad Dog 
  • Steamhead
    Steamhead Member Posts: 16,904
    Mad Dog_2 said:

    Baso switch?  Mad Dog 

    Or a bad thermocouple, that's what I'd check first.

    @Amaster , where are your parents located? We may know someone who can fix this.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,126
    That’s not enough information to answer your query. Since that boiler was manufactured over 60 years ago, there’s no telling what controls are in that thing. So many years ago, they used different parts compared to what is used today.

    Edward Young Retired

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