No steam pressure?

Steve Garson

I just installed a sensitive pressure gauge with a pig-tail onto my steam boiler to measure the pressure. Last month, I installed two pairs of Gorton vents on the returns to improve the venting. I wanted to see the gauge needle move, but it didn't move an ounce the entire burner cycle.

I then noticed that one of the pairs of vents was still cold, so it probably never closed, which would explain the lack of pressure. Yet all the radiators are hot and the burner shut down.

To clarify: one pair of vents is located near the ceiling above the boiler, where one of the returns takes a 90* to the boiler. The other pair are located at the ceiling about fifteen feet from the boiler, as the return take a 90* to go down to the floor to the pipe that goes back to the boiler. This is the set of vents that never get warm during the cycle, although the pipe below get warm later, but never hot enough to close a vent.

Can anyone explain to me what is happening? I shouldn't complain since the house is comfortable, but I want to tune everything so it is as perfect as possible.

Thanks

Alan(CaliforniaRadiant)Forbes

The only thing

between the gauge and the boiler is the pigtail and tapping; check the two to make sure they are clear; perhaps too much pipe dope?

Did you say the gauge increments are in ounces?

Also, check the gauge to make sure it works.

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Steve Garson

I thought that might be the problem. I slid a hanger wire down the gauge pipe and it went down to the hot water. Used teflon tape carefully on threads. Tested the gauge by blowing into it. The scale is 1 to 5 psi, with 1 ounce increments.

Steve Garson

I just took the gauge off and ran a hanger down the tube into the boiler water. Is it likely that this gauge pipe goes into the water and that is why it sees no pressure? I ran the boiler with the gauge off and no steam came out.

Is it permissible to put a tee on the pig-tail that holds the pressuretrol, which obviously sees pressure?

Dale

Vents

If the vents are on the supply mains the only way they can be cold is if they are stuck closed, think about it if they were open steam would come out. I guess I should say if you have a vacuum pump system this may not be true but these are pretty rare. If your house heats nicely at all the rads you are one of the lucky persons whose system is running at only a few ounces of pressure and that is good. You say the system is cycling off, what is turning it off the stat or the pressuretrol? Is sounds like tha stat only but you could check. The pigtail should be in the steam portion of the boiler, that's why is is commonly tapped to the top of the low water cut off. However since water is not compressible a guage below water line will read pressure. I guess I would use the clear tubing off the boiler drain to the ceiling trick 28" per pound to see what the pressure really is when the boiler is on.

Steve Garson

Main Vents not getting hot

On Steamheads suggestion, he thought that there might be a dip in the pipe preventing steam from reaching this vent, located on the dry return, around fifteen feet from the end of the main. I took off the vent and held by finger on the hole as the boiler cycled. I was able to feel a pulsing of air and heard a slight gurgle sound, which tells me that the pitch of this pipe has some water sitting in it that blocks the venting.

My choices are: (1) tap a hole at the end of this main and attach the vent there or (2) cut and thread pipe to correct the pitch of the dry return.

I don't experience much knocking, so it seems the tap would be easier to perform. Since the return does eventually drain, is this a reasonable approach, or should I just pay a plumber to trim an inch or two and put in a union to improve the pitch?

Steamhead

Tap the hole

much easier and simpler, and you'll get better venting as a result. Tap it to 1/2" pipe thread- that's big enough for two Goeron #2 vents.

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Steve Garson

That's what I'll do then. Many thanks for all your assistance. I would like to make a donation in your name as a token of thanks. What's your favorite charity?

ThermalJake_2

Bad Guage???

Sounds like a bad guage. What is the Vaporstat set at? (say that 10 times fast) If you have vents on the radiator return, you should (hopefully) never get steam there. The guage will read the pressure at the boiler regardless.

Jake

Steve Garson

Just installed gauge next to pressuretrol - 0 psi

with a tee and spent 45 minutes watching for pressure increase. I now see that my boiler cycles only on thermostat call for heat, the mercury switch nor the pressure gauge move through an entire cycle.

All radiators get hot. New main vents, although one set never close due to a dip in the return pipe that the vents are mounted on. Until I tap a hole on the related main to move these vents to, should I plug the whole for these vents, i.e. is that what is preventing pressure from building? I suspect I am wasting a lot of oil right now. And I thought it was the gauge connection.

lchmb

May be off here

But if your house is heating good, the system is running good and not loosing large voluum's of water. I would not worry about the guage. Unless you have an extremely sensitive guage you probably will never see a pressure increase. My Grandfather's house has run for a long time (since I was a young kid) and never shown a pressure increase.

Steve Garson

But my gauge measures ounces. I have to believe that there must be a leak somewhere and the burner is firing much longer than needed. Perhaps not, but with the price of oil, I want to tune this thing perfectly.

Steve Garson

My mains heat up to 212 in just four or five minutes. It takes 45 minutes for the room with the t-stat to reach temp so the boiler runs for 45 minutes