Steam Boiler not stopping, steam coming out of overflow at boiler

cberhomengarden

This morning we woke up to a smoke detector going off in our basement.

Upon investigation, our steam boiler was throwing steam out the emergency overflow valve on top of the boiler. When I looked at the pressure gauge on the boiler, it was up to 10 pounds!!

We immediately turned off the thermostat and the boiler shut off.

Pressure has gone down to zero.



I checked the pressure gauge and it is set at 1/2 and the differential is set at 1. This is how it has been set for the past 8 years we've lived here (thanks to Dan's Steam Heat homeowners guide).



We turned the boiler on the first time on Nov 1st and at that time I emptied out some dirty water from the blow down valve and added a little water so the water gauge was half way full. I do this weekly throughout the heating season.

The system has been performing fine the past few days.

We have the thermostat set constant throughout the day, but at night the heat temperature is set lower, and it kicks back on in the morning.



We changed the batteries on the thermostat thinking perhaps it was not registering the heat in the room and not telling the boiler to stop working.

I have not turned the system back on until I researched what might be wrong with it.



Any ideas as to what went wrong and what else I can do by myself before calling a steam heat pro in?

Thanks in advance.

Rich_L

Pressure Control

It's very likely your pressuretrol. Either the control is no longer working properly, contacts not opening when pressure is reached, or possibly the piping leading to it may be plugged with "mud". Is there a "pigtail" leading to the pressuretrol?  

BobC

Plugged pigtail or pressuretrol

That sounds like your pigtail is plugged. Disconnect the wires (shut off the power at the fuse box FIRST) and remove the pressuretrol and that pigtail. If the pigtail is clogged, clean it or replace it. Also check the bottom of the pressuretrol where it threads onto the pigtail and make sure that little hole up in the brass fitting is clear.



If the pigtail is clear and there isn't any gunk in the bottom fitting of the pressuretrol then that pressuretrol might have gone south.



Bob

cberhomengarden

Pigtail

Thanks for your replies!

Yes there is a pigtail leading to the pressuretrol that comes up out of the top of the low water cutoff valve.



Our low water cutoff was replaced Fall 2011 as it was no longer functioning (construction worker dropped a ladder onto it or something).

I believe the pigtail was also either replaced or cleaned out at that time.



Thanks, we will check to see if the pigtail is plugged and go from there.

Rich_L

Good luck

and let us know!

cberhomengarden

Thank You!!

I just wanted to come back and thank the people who helped me fix my boiler problem!

We took the pig tail off the low water cutoff & cleaned it out.

It didn't seem too dirty in there.

However, I realized when we were reassembling it, that when we put it back on, we didn't put it back exactly as it was (I had taken a photo to be sure what it should look like). I realized that the pig tail had been facing the wrong way before (you could see through the donut hole while facing the pressuretrol). Turns out that the way we put it back was how it is recommended in Dan's book on steam heat.

So between cleaning it out and repositioning it, our heat works nicely again!

I'm so thankful to have you guys as a resource to help fix the not so difficult things.

Saved us a lot of money.

Thanks!