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Why is Boiler not starting automatically?

chip7
chip7 Member Posts: 6
My Boiler now usually does not turn on when the
thermostat is calling for heat.
It is a Weil McLain boiler with automatic flue
damper and spark ignition and a White Rodgers
1204-5 Type B2 Pressure Control. All were
installed 35 years ago.
Sometimes I can start it after its been off a
while by tapping on the pressure control. The
pressure gauge gets as high as 3 psi.
My check of the voltage across the pressure
control terminals shows 0 volts when the
thermostat is not calling for heat and 24 volts
when it is whether the boiler is on or off.
Can you help me with this problem?

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 18,915
    Pressure control isn't working properly. Perhaps as simple as the pigtail being plugged up and not letting it reset. Perhaps misadjusted. Perhaps... just plain busted.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • chip7
    chip7 Member Posts: 6
    A few questions:
    1) What is the proper adjustment?
    2) How would I unplug the pigtail?
    3) If I must replace the White Rodgers 1204-5 Type B2 pressure control, which one would I buy?
    Thanks.
  • Jamie Hall
    Jamie Hall Member Posts: 18,915
    The proper adjustment is for the boiler to cutout at about 1.5 to 2 pounds,and cut back in at 1 pound. I'm not that familiar with that particular control, but I'm sure if you study it you can figure out ow to set it.

    To clean the pigtail, you need to unscrew the control from the top of the pigtail (may have to disconnnect the wiring -- if so, note what goes to what, and TURN THE POWER OFF!) and unscrew the pigtail from the boiler -- which may be easier said than done on a boiler that age. Then if you can blow through it you're OK. Otherwise try to run a fine wire or some such through it -- but you may be better off with a new brass one.

    If you want to replace the control, I would suggest a Honeywell pressurestat for most steam systems, or a vaapourstat for a vapour steam system --but I would need to know more about your system to say which one.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • chip7
    chip7 Member Posts: 6
    Thanks for all the info.
    I have a steam system so I would probably need the pressurestat. I have a Weil McLain Type EG boiler with automatic flue
    damper and spark ignition and a White Rodgers
    1204-5 Type B2 Pressure Control.
    Would you need any more info to pick the one Honeywell pressurestat I would need?
  • Jamie Hall
    Jamie Hall Member Posts: 18,915
    PA404A1033
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Abracadabra
    Abracadabra Member Posts: 1,948
    might as well put in a vaporstat if you are going to replace the pressuretrol
  • chip7
    chip7 Member Posts: 6
    Actually I am replacing a 35 year old White Rodgers
    1204-5 Type B2 Pressure Control.
  • Abracadabra
    Abracadabra Member Posts: 1,948
    chip7 said:

    Actually I am replacing a 35 year old White Rodgers
    1204-5 Type B2 Pressure Control.

    yes.. that's a pressuretrol... actually pressuretrol is honeywell's name for the same thing... Kind of like Kleenex and Xerox.
  • chip7
    chip7 Member Posts: 6
    I have a steam system so I would probably need the pressurestat. I have a Weil McLain Type EG boiler with automatic flue
    damper and spark ignition and a White Rodgers
    1204-5 Type B2 Pressure Control.
    Would you need any more info to pick the exact right one Honeywell pressurestat I would need?
  • vaporvac
    vaporvac Member Posts: 1,520
    I agree with @Abracadabra, since you have to replace anyway, you might as well put in a vaporstat to keep the pressures low. a Vstat is also for steam, it's just for keeping the pressures lower than a ptrol Most steam systems can benefit from this. Is your system one pipe or two?
    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
  • Abracadabra
    Abracadabra Member Posts: 1,948
    chip7 said:

    I have a steam system so I would probably need the pressurestat. I have a Weil McLain Type EG boiler with automatic flue
    damper and spark ignition and a White Rodgers
    1204-5 Type B2 Pressure Control.
    Would you need any more info to pick the exact right one Honeywell pressurestat I would need?

    I install vaporstats on 1-pipe steam systems all the time. A vaporstat is also a pressuretrol/ pressure control. You can get a vaporstat with a 0-4psi range on it, although I'd suggest using it with 1psi and a diff of 8-10oz. to start.

  • chip7
    chip7 Member Posts: 6
    Thanks again for being patient with me. My lack of knowledge in this field must be obvious to you.
    It seems there are many different models of the vaporstat and I was hoping to get an exact model number. Possibly this is impossible without your knowing my system exactly.
    P.S. My system is a one pipe one.