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Is My Vaporstat Causing This Problem

FJLFJL Member Posts: 354
Around midnight I noticed that my boiler hadn't turned on even though the t-stat was calling for heat. I have single pipe gas steam, a Burham IN 11, and a Honeywell vaporstat (the kind with the mercury tube inside). I visited my boiler in the basement and didn't notice anything amiss. The water level seemed fine. I did not smell gas.

Then by accident I turned off the switch for the electrical to the boiler. I then turned it back on, at which point the red light on the low water cut off blinked. Then the burner turned on and the boiler started to make steam. It did make an extra kind of noise that I usually don't hear at start up. Very hard to explain. I thought it might be water filling into the boiler but the water gauge wasn't disturbed.

The boiler then made steam as usual. Then it cycled off due to pressure and never turned back on, even though the t-stat was calling for heat. That was around 1:00 a.m.

I kept waiting for the heat to turn on again. By 2:20 p.m. there still was no heat. I went down to the basement and turned the electrical switch and the boiler turned on again, same as before, and made steam until it cycled off. It did not cycle on again even though the t-stat was not satisfied.

I guess I need someone to come out and look at it. But it is the middle of a blizzard. I don't know if I can get anyone out on a night like this.

I don't know how fast I can get someone out. Any thoughts about this problem would be appreciated.



  • FJLFJL Member Posts: 354
    Boiler Turned On

    Now I'm really confused. Maybe the t-stat is not working? T-stat set at 70. Room temp has been below 70 for two plus hours. Now the boiler turns on at 5:45 a.m. T-stat says room temp is 65.
  • Al Letellier_21Al Letellier_21 Member Posts: 402
    edited December 2010

    Sounds to me like a very common issue......check the pigtail under the vaporstat. IF it is plugged or restricted, pressure will trip the switch and shut down the boiler like it should at pressure, but the pressure can't get back out and the pressure switch keeps the boiler from starting again. To check this out, sometimes just a hard knuckle hit on the vapor stat will restart the boiler, It so, shut off the boiler and remove the vaporstat and pigtail and clean it out........
  • FJLFJL Member Posts: 354

    My v-stat is not connected with a pigtail. The boiler seems to be working fine now It has been working seemingly non stop since 5:45 a.m. to get from 65 to 70 and to say at 70. I am baffled.
  • FJLFJL Member Posts: 354
    Maybe T-stat is the problem ...

    I'm thinking that the t-stat is the problem. It says "Heat On" all the time regardless of whether the boiler is on. RIght now, the t-stat is reading 67 degrees and the t-stat is set at 69 but the boiler is off.
  • Check the stack damper.......

    If the boiler has been installed in the past 5 years or so , the stack damper is another likely culprit.  This is the device that sits on the top of the vent pipe connection at the back off the boiler.  The newert models often times do not operate properly and the "on" contacts for the burner  do not make.  There is a switch on the round motor housing that is attached to the vent pipe that is marked normal and manual..Place the switch in the manual position. And, as always, check to make sure the exhaust gases are being drawn up the chimney.
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert

    Noisy Radiators are a Cry for Help
  • FJLFJL Member Posts: 354
    Stack Damper

    I see the draft hood and the vent damper but I don't see any kind of switch like what you described, at least not in the area of the hood or damper.
  • FJLFJL Member Posts: 354
    Low Water Cutoff

    Maybe the low water cut off is the problem. I flushed the LWCO and as I was doing that the boiler kicked on.
  • strange noise

    there could be some sort of relay/transformer on your boiler which is going bad. on mine it was the fan center. the noise it made was irritating enough to replace it.--nbc
  • FJLFJL Member Posts: 354
    Tech Came Out

    I had a technician from the installer come out and take a look. A snow drift had blocked the sole vent allowing fresh air into the small boiler room. He flushed the LWCO and emptied a lot of dirty water from the boiler. He cleaned my sight glass, which was so dirty that it did not empty when he opened the bottom nut. He cleaned the probe of our second, back up LWCO. He also increased the pressure to around 10oz/4oz. It is working like a charm now. The apt is very warm. The high winds are causing the boiler to work a lot to maintain the set temp of the t-stat.

    I asked him to put a low pressure gauge on my boiler, but he refused, saying that they were against NYC code and that only a gauge that went up to 30 psi could be installed. I told him that I didn't want to replace gauge, just add it to the tee to which the pressuretrol and v-stat are set, and he said that was still in violation of the code, even to just add an extra low pressure gauge. I never heard of that before.

    Bottom line is that the boiler is working fine and I need to b more careful about keeping the water clean.
  • crash2009crash2009 Member Posts: 1,484
    don't forget

    about keeping the fresh air vent free of obstructions too.
  • SteamheadSteamhead Member Posts: 13,866
    I never heard of that either

    in this area, inspectors don't care if you have a low-pressure gauge as long as the 30-pound gauge is there. I've asked them and they tell me there is no Code provision that outlaws this. 
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
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