Old mclain weil boiler with electronic ignition slow to start

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by patzeram, Nov 7, 2010.

  1. patzeram

    patzeram New Member

    Messages:
    2
    Location:
    Long Island, NY
    Old Weil Mclain boiler with electronic ignition slow to start

    I have an old Weil Mclain boiler with an electronic ignition. In the past when I turned on the thermostat for the heat, I would quickly hear the clicks for the ignitions and almost immediately the boiler would fire up. The whole process would take about 30 seconds.

    It didn't work the other day so I called the plumber. The flame sensor, the pilot assembly and the three prong pilot was replaced. It now takes a few minutes before it fires up after I turn on the thermostat. Is this unusual and what causes the delay? Could it be a faulty part? I am very concerned about the reliability with winter coming soon. It's cold enough already here.
    Last edited: Nov 7, 2010
  2. Hairyhosebib

    Hairyhosebib New Member

    Messages:
    173
    Location:
    Arizona
    Does it have a Fire eye? Never messed with boilers much.
  3. patzeram

    patzeram New Member

    Messages:
    2
    Location:
    Long Island, NY
    Yes it does.
  4. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    A delay shouldn't affect the average temperature but might give you temperature swings wider than necessary.
  5. rmelo99

    rmelo99 Network Engineer

    Messages:
    349
    Location:
    Connecticut
    Your turning on the t-stat doesn't call the boiler to fire directly. Your t-stat talks to the aquastat (grey box) on the boiler. When calling for heat from the t-stat the aquastat willl usually run the circulator to begin moving water.

    If the water in the boiler is colder than the setting on the aquastat (180deg let's say) then the aquastat will send a signal to the gas valve/ignitor to fire up and heat the water. If the temp of the water in the boiler is 200deg then the aquastat will simply run the circulator to get hotwater into your radiators. If the water temp in the boiler drops and you are still calling for heat then the boiler will run the burner(gas or oil)

    this is the readers digest version, but generally that how things work. If you are calling for heat from a COLD boiler then the burner will always fire to get the water temp up.
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