9psi of pressure in a 1-pipe steam system

dtmaine

Hi there,

I am entering my first heating season in a 165 year old home that I recently purchased. We have a 1-pipe steam system and I have been doing a lot of reading (much on your wonderful site) to learn about this seemingly 'artful' form of heating. We've got 5 radiators, and as I have been firing things up to test in the last few days I'm getting a mix of behaviors:

- Everything seems to get hot at roughly the same time, but there is strong hissing coming from several of the radiators
- The hissing was so strong that it was making me nervous, so after reading about pressuretrols I went and inspected my own boiler, to discover that the pressure gauge on my boiler was reading almost 10psi -- far above what I have read is normal and necessary.
- The pressuretrol was dialed to 2psi. I turned this down to .5, but still the pressure in the system did not reduce. Shouldn't it already have been limited to 2psi to begin with? Is it possible I have a faulty pressuretrol?

I plan to get the system serviced ASAP, but any help in the meantime would be appreciated. Also, if anyone can recommend a contractor that knows steam in southern Maine area, all suggestions taken!

Thanks,
Dustin

neilc

Getting a Steam pro to look at your system with you is a good move.
There are a couple books available on this site which would also be a good read,
"We've got Steam" is a must read for first timers.
Between the Pressuretrol and the boiler you should have a pigtail, which is could be clogged,
If you are handy you could try removing the Ptrol, and pigtail, and make sure all is clean and free flowing,
Turn the boiler off and be sure the pressure is zero.
There is some wiring and wrenching to do.
carefully check the inlet hole to Ptrol and clean if needed,
clean the pigtail that you can blow thru it,
and clean (poke) the hole into the boiler,
may need to do same for the gage, that may be clooged also.
This all depends on your setup.
Maybe post a picture or 2 of what you're looking at, the controls and boiler, and near piping.

BobC

Sometimes pressure gauges lie but the fact the air vents are loud makes me thing your pressure is indeed to high. The pigtail between the boiler and the pressuretrol could be clogged. If that pigtail is clogged the pressuretrol has no idea whats going on inside the boiler.

Turn off the boiler at the breaker and remove the pressuretrol. You will have to disconnect the wires from the pressuretrol to unthread it, make sure you note what screws the wires go to if the pressuretrol has three terminals. Then using a wrench remove the pressuretrol.

If you can blow into the pigtail with little or no resistance it is clear, if you can't it's blocked. In any case it's good practice to remove that pigtail every few years to clean it out or replace it. If your replacing it use a brass pigtail not one made of steel.

If the pigtail is clear your pressuretrol may have failed but I would check that the small hole at the base of the brass fitting (at the base of the pressuretrol) is clear. I would also be leery of the pressure gauge, a lot of us have added auxiliary low pressure gauges because the stock 30 PSI one is pretty useless at 1 or 2 PSI.

Bob

RJ_4

Could be the pig tails connected to the press. and limit controls are plugged, time to have a licensed boiler contractor check it out. I would contact U.A local 716 ask for a contractor was going to send this earlier, neilc went into greater detail

neilc

yeah, NeilC is not a pro so shake some salt on that,
There is a find a pro locator on here too, punch in your zipcode , , ,
we still want to see pictures

Fred

While you're waiting on a Pro do do some maintenance, and when you check the pigtail, under the Pressuretrol, take the cover off of the Pressuretrol (screw at bottom center of front cover) and make sure the white dial is set to "1" (facing forward). That dial setting, plus the .5 setting you set on the front scale is actually what sets you Cut-out pressure (Pressure at which the boiler will shut down). The burners will come back on when the pressure drops to the level set on the front scale (.5PSI). Getting pressures as high as you see, and with all the hissing at the radiator vents, it is very possible that the radiator vents and even the main vents could be damaged. You will need to watch those and see if the open and close like they should, once the pressure issue is resolved. If they don't, replace the ones that either stay open and lets steam escape of that stay closed, causing the radiator to stay cold.

dtmaine

Thank you all very much for your insight and suggestions. I've taken a couple of photos (below). I haven't had a chance to take the pigtail off yet, but will try tomorrow.

In the meantime, after letting the boiler cool down and being off all day, it seems that I have a faulty, or at least incorrectly calibrated, pressure gauge. At dead cold, gauge is reading 6psi. If it's just mis-calibrated, would I be correct in assuming that my system is actually running at 3psi (based on the 9psi reading I was getting while it was firing)?

Thanks again for all the useful comments, and if you can tell anything else from my setup in the pictures, much appreciated! Meanwhile, I will seem a steam pro in the area.

BobC

That gauge will have to be replaced but I would still verify the pigtail is clear.

The water in the gauge glass seems clean, does the water column move about some when the boiler is steaming?

How dirty is the water when you do the blowdown of the LWCO?

Have you tested the LWCOto be sure it actually works?

Bob

dtmaine

BobC,

Today while the boiler was running I observed the water column, it moved around up and down probably within a tolerance of about 2"

I haven't done the blowdown -- is this something that needs to be done regularly? (The person I had service the furnace last year didn't mention anything, but we weren't yet living in the house and so were barely running the system all of last winter).

Also, excuse my ignorance, but is this when I open the water valve that is basically directly below the pressuretrol? Definitely I want to do this if I ought to, what should I look for when I do?

Thanks again,
Dustin

dtmaine

Also, when I replace the pressure gauge, do you recommend I replace it with a low-pressure gauge?

Fred

I can almost guarantee you that pigtail and the tapping that it is mounted on on that McDonald Miller #67 Low water cut-off is 100% clogged. I had a similar set up and it just doesn't work well. You need to clean that pigtail and the opening in the LWCO at least twice each heating season or move the Pressuretrol over to where the gauge is mounted. Use a 1/4" Tee and a couple nipples to mount both the Gauge and the Pressuretrol on the same boiler tapping or have the Steam Pro do it for you when he comes to do maintenance. Also, consider having him put a 0-3 PSI gauge on the boiler as well. That 0-30 PSI gauge is virtually worthless in terms of seeing what your boiler is really doing. It is also very possible that the pipe your current gauge is mounted on is also clogged, holding some pressure on the gauge side of that pipe. It should be taken off and checked/cleaned also.

BobC

If the water in the gauge glass is moving that means the glass is seeing the correct water level. Once you have the pressure between 1-2# if that water is still moving that much the boiler may need skimming.

Manual LWCO's tend to fill up with sediment if they aren't blown down on a regular basis. If you don't do this it might not work when a problem occurs. That's the valve with the yellow handle at the bottom of the LWCO. That valve should be opened every week or two during the heating season while the boiler is making steam. Put a 5 gallon bucket underneath it and rnn it till the water is clear.

The insurance company wants the 30# gauge but once things are ironed out it's good to have allow pressure gauge on there. Fred's suggestions would work just fine.

Bob

dtmaine

Thanks for all the extremely helpful feedback! Keep you posted as I complete the various steps outlined here.

Maine Vent

Hi dtmaine I live in Brunswick, I have had steam for 20 years. I have a very reliable and talented service tech. Hi name is Aaron Hamilton, he lives in Brunswick also. He advertises on the this web site under the Find a Pro link.
Good luck

dtmaine

Thank you MaineVent, that's really helpful and I'll give Aaron a call.

dtmaine

Update:

So I took your suggestions today and removed the pigtail and the pressure gauge. Wowzas. Pigtail was filled with sludge, and you can see what the nipple going to the pressure gauge looked like (below image). Yeah.

Anyway, I replaced the pressure gauge, thoroughly cleaned the nipple leading to it, and also replaced the pigtail and did a LOWC blowdown (a. it works; b. water is now clean coming out).

I intend to add a low pressure gauge, although the 4 local plumbing supply stores I visited to find the other components today did not carry, so will have to special order.

Ran for about an hour today until the radiators were hot, however the pressure gauge I installed wasn't reading anything -- I don't know if that's because its not sensitive enough to pick up the low PSI or what, but it is definitely now a clean connection.

Lastly: one of my radiators (they were all disconnected to install new flooring) is leaking terrible once the condensate starts flowing, at the connection at the floor. I disconnected last night, cleaned the threads, and applied around 5 rounds of thread tape.

Any other suggestions to stop up the leak?

THANKS!

Fred

The 0-30 PSI gauge usually doesn't show any pressures at the low end of the spectrum. Most of us use the 0-3 PSI gauge:
http://www.valworx.com/product/low-pressure-gauge-25-0-3-psi

Your radiator that leaks should be coupled to the valve with a union and spud, matched to the valve. It should not take any tape or dope. Just clean it up and tighten it up. Post a picture of that connection and let's see what it needs.
Glad you got all that crud cleaned out!

dtmaine

Fred,

I've ordered a low pressure gauge and will install once I get it.

I gave the radiator connection a little more torque with the pipe wrench and will test again this evening. Any need to worry about overtightening with this connection?

Thanks again,
Dustin

Jamie Hall

A union like the one on that radiator shouldn't need any tape or goop -- the seal is between the two faces of the union. However, it is important that the two faces really line up properly, and that they are really truly clean and smooth -- any roughness or gunk on them will almost surely cause a leak. It often helps to rock the radiator just a little bit when tightening...

Fred

@dtmaine , I see some teflon tape on the union. It will likely continue to leak when you test it. Take the union lose, remove all tape and clean both mating surfaces well and re-connect. As Jamie said, make sure the nut threads on straight and rock the radiator a bit, when the nut gets finger tight so that it seats properly and continue to tighten it up good and snug but not excessively. If it still drips a bit, tighten it up a bit more until it stops.
Looks like a very nice job on the floors too!

dtmaine

Leaks are taken care of, thanks again!

Roddy

I'm a novice too, and have a one pipe system. I've learned a lot on this site, and it's been a great help. A question: Do all of the piping and connections to your radiators look like the one you pictured/attached? One of mine looked like that, but I figured it'd been modified as the other 9 radiators had a connection that looked different than the one. I changed the one back to what I assume was the original design, and the radiator did heat somewhat better. The original connection piece had more of a belly or balloon feature on it. It wasn't just a straight pipe connection in appearance. Comments from the experts?

Fred

Roddy said:

I'm a novice too, and have a one pipe system. I've learned a lot on this site, and it's been a great help. A question: Do all of the piping and connections to your radiators look like the one you pictured/attached? One of mine looked like that, but I figured it'd been modified as the other 9 radiators had a connection that looked different than the one. I changed the one back to what I assume was the original design, and the radiator did heat somewhat better. The original connection piece had more of a belly or balloon feature on it. It wasn't just a straight pipe connection in appearance. Comments from the experts?

@Roddy Valve designs vary a bit from brand to brand. Some have a bit more contour to them than others but, in general they are similar. To your question about how the connections look; they can vary significantly, depending on the preferences of the installer and/or the need for the radiator to be in a specific location. Some may have elbows (either 45's or 90's) on them, some may have varying length nipples on them, etc. The one thing that most will have in common is that the valve and the spud (flared nipple) are typically a matched set and is the connection that ties the radiator side to the valve. Of course, over the years, people have worked on these systems and even removed the valves completely and just used a union to tie the radiator to the supply pipe, along with any number of other questionable repairs.

Roddy

Makes sense. Thank you.

dtmaine

Update 2:
Today I added the low-pressure gauge and fired things up. Good news: gauge works brilliantly.

Bad news: once things got hot, pressure raced past where my pressuretrol should have shut things off -- I had the cut in set to .5, the differential to 1 -- my understanding is that things should have shut down at 1.5.

I turned the boiler off as pressure approached 3psi. I'm assuming my pressuretrol is shot and needs to be replaced. Safe assumption?

Thanks again.

Jamie Hall

That's not good. But before you junk the pressuretrol, check and make sure that the opening at the bottom of it is clear. Also check and make sure that nothing has come apart inside -- you are right down at the lower limit of those things, and they sometimes have a way of falling apart.

Fred

Also, here is the procedure to re-calibrate the Pressuretrol. It's not unusual that they need to be calibrated. As Jamie said, make sure the linkage that connects the scale on the front of the Pressuretrol hasn't come loose. You can turn that screw so much that the link drops off (inside the cover). I am a bit concerned why the boiler pressure rose that much?? How long did the boiler run and were you trying to raise the house temp several degrees? A boiler running for 45 minutes or more may build pressure, especially if it is somewhat oversized.
Here is the calibration Procedure:
Inside the Pressuretrol, right below the micro switch, there is a pivot arm. At the end of that arm you will see a screw pin that is activated by the diaphragm at the bottom of the Pressuretrol. If you look very carefully at that screw pin, you will see it actually has a tiny (I mean tiny) hex head on it. It takes a .050 hex wrench and you can turn it clockwise (Towards the bottom of the Pressuretrol to decrease the Cut-out pressure or counter clockwise to increase the cut-out pressure (which none of us want to do but who knows, your Pressuretrol may be really screwed up!). Turn the power to the unit off first. You may find the first attempt to turn that screw a little bit stubborn (relatively speaking) because it has some Locktite on it but it does turn. Don't turn too much, a fraction of a turn goes a long way towards getting it adjusted where you want it (maybe 1/32 inch turn to start with). You may need to play with it to get it exactly where you want cut out to be.

JUGHNE

When you took off the pressurtrol to clean the pigtail, did you unwire it and unscrew it off of the pigtail.....or did you remove the 4 screws on the bottom of the control so as not to have to unwire it?

dtmaine

Thanks for the suggestions.
@Fred: I intentionally cranked the thermostat in order to test the system, so the boiler was firing for probably about 30 minutes when I went to check things out, right as the radiators were starting to get hot. Also, as to the rising pressure, I have a couple guesses... for one, the house originally had at least 9 radiators, but the previous owner removed those that were downstairs, leaving only 5 now. So boiler is definitely oversized for its current use. Additionally, while there are two air vents installed near the boiler, it seems like one isn't functioning properly, and they seem to be oddly placed. There is a plug at the end of the main line where I suspect another vent once was. I've ordered a Gorton #1 to hopefully address that issue.

@JUGHNE : When cleaning and replacing the pigtail, I unwired the whole unit and unscrewed it from the connection with the pigtail, careful to re-connect the wires as they were connected originally (there are two: blue and black in my case).

In any case, rather then mess with re-calibrating the pressuretrol, I ordered a a pre-owned replacement for $35 that supposedly has never been out of the box.