Boiler won't fire unless pressuretrol cut-in as 5psi?

tjdumez

What is going on here? My boiler won't fire unless I crank the pressuretrol up to 5 psi cut in. I don't want it that high but it shuts off if I dial it back. Anybody have any ideas? Bad unit?

ChrisJ

I'd check the pigtail and other plumbing to the control.  Sounds like it may be clogged

tjdumez

ChrisJ said:

I'd check the pigtail and other plumbing to the control.  Sounds like it may be clogged

I took the pigtail off yesterday, it had some gunk in it so I flushed it out with water for quite a while and it is for sure clear today. That threads into a bushing in the side of the boiler (steam chest probably? I'm not the most familiar with what's on the otherside of the cover) Could it be clogged before it exits the steam chest somehow?

The pressure gauge also reads 0 but they are coming out of separate pig tails. I flushed that one too. The pressure gauge is tee'd off a section of pipe with a valve that purges steam when its running, so that's not clogged.

JUGHNE

The threaded ports going into the boiler may be somewhat plugged. Should run a small brush thru those holes well into the boiler.

mattmia2

What is the differential set for?

tjdumez

mattmia2 said:

What is the differential set for?

1 psi

Jamie Hall

Do you have a reliable low pressure gauge, in addition to the 30 psi gauge which is required by code? That might tell you a little more about what is happening.

Pressuretrols -- particularly if they have had people playing inside them -- can go out of calibration, but not that far unless they are damaged in some way.

JUGHNE

Or they can also come apart on the screws inside if set too low.

tjdumez

Jamie Hall said:

Do you have a reliable low pressure gauge, in addition to the 30 psi gauge which is required by code? That might tell you a little more about what is happening.

Pressuretrols -- particularly if they have had people playing inside them -- can go out of calibration, but not that far unless they are damaged in some way.

Funny you ask that, I just installed some main vents where there weren't any to begin with and I have a 15psi gauge in the mail that I'm going to put up there right next to it to read main pressure.
For some reason the pressure gauge on the boiler is reading 0 all the time. It's brand new, I just swapped the 30psi with a new 15psi I got a few weeks ago to see if the gauge was bad, but it still reads 0 when it's on. I just took all the nipples and pigtails out to make sure they were clear and even stuck a bore-scope in side the side of the boiler to look for any obstructions. There is nothing blocking it, I can blow air through both the pressuretrol pigtail and the gauge pigtails and everything in between. Baffling.

Regarding calibration of the pressuretrol - I think I know what you're saying. If I go down there and turn the screw past 0psi or past whatever the high limit is, is that the same as calibrating it?

mattmia2

If the systme is consuming steam at the same rate as the boiler, it should never build any pressure. Unless the boiler is oversize it shouldn't build more than a couple psig which even a 15psig gauge may have trouble indicating..

JUGHNE

The control is a closed switch until some pressure is applied to it.
Look inside for the adjustment linkage that might have become unscrewed. If adjusted too low on cut in it may not close the switch.
Pictures if you can.

You want your system to operate at 2 PSI or less, should never see 5 PSI on any gauge.

tjdumez

JUGHNE said:

The control is a closed switch until some pressure is applied to it.
Look inside for the adjustment linkage that might have become unscrewed. If adjusted too low on cut in it may not close the switch.
Pictures if you can.

You want your system to operate at 2 PSI or less, should never see 5 PSI on any gauge.

AHA! Linkage... that was it. This tiny little set screw had blue marker over it and it looked undisturbed, like it came from the factory like that. I set the pressuretrol to 0.5psi cut in like you see in the picture and adjusted that tiny screw until the boiler kicked on. Tada.

Now to address my issue of 0psi - I don't think anything is wrong with my gauge or clogged piping, I just remembered I have a pair of leaking radiator valves. A hole in the system would cause pressure to be 0. DUH!

JUGHNE

If you shut off the 2 leakers and take them out of the picture, that may let you see some pressure build up.
It may take 1/2 hour or so.

tjdumez

JUGHNE said:

If you shut off the 2 leakers and take them out of the picture, that may let you see some pressure build up.
It may take 1/2 hour or so.

Problem is they leak when they're off too - right through the stem of the handle. I already have the valves, I just need to find a minute to swap them out. Thank you everybody, I will report back when I get new valves in!

nicholas bonham-carter

Just fix the valve packing, and save yourself a LOT of trouble, instead of changing the valve.--NBC

mattmia2

nicholas bonham-carter said:

Just fix the valve packing, and save yourself a LOT of trouble, instead of changing the valve.--NBC

Well, and the washer. but still a lot easier than replacing it.

tjdumez

mattmia2 said:

nicholas bonham-carter said:

Just fix the valve packing, and save yourself a LOT of trouble, instead of changing the valve.--NBC

Well, and the washer. but still a lot easier than replacing it.

Yes and yes, I understand, however they are both unsightly wearing 9 coats of chipping paint so it's time to go. I've replaced one already I should be able to do it again.