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crane boiler system

Looking for info, boiler won't get the house to the correct temp. Thinking it's air in the system, everything else seems to be working properly. Cycles through, pump is going, pilot stays lit, psi starts below 10 then gets close to 30 after it fires. The temp was 1 out side and the house went from 62 to 59 overnight. Thermostat set at 70. The next night I got the house to 70 with a small space heater. House is only 900 sq ft. Also you can hold your hand on the heater tines of the baseboard heaters, during full operation. Burners are clean, pilot is clean. 100 series crane boiler any advice is appreciated!


  • lchmb
    lchmb Member Posts: 2,997
    sounds like an issue with your expansion tank which probably caused your p.r.v to activate. this allowed air into the system so your zone is air bound... just a thought...
  • hot_rod
    hot_rod Member Posts: 16,334
    Must be circulating some if it maintains 59? Any changes to the system, how hot is the boiler running? Does the boiler shut down ever?

    I assume it has kept up in the past?

    The pressure should not change that much, the relief valve typically pops at 30 psi. You may need a new expansion tank, or you have a waterlogged compression tank.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    EBEBRATT-Ed Member Posts: 12,023
    Almost sounds like the circulator isn't moving water and your only get gravity flow.

    Maybe the pump is running, broken coupling, bad impeller.
    Are the burners on? Could be a gas issue as well. Low gas pressure
  • jsndltn
    jsndltn Member Posts: 2
    Can anyone give me some help understanding my old crane boiler?
  • lchmb
    lchmb Member Posts: 2,997
    jsndltn you should start your own post..may get more responses. Be specific as to what your issues are and what help you need