Not Building Pressure - Suggestions?

NJNavigator

Greetings all...

I have a three story building, built in 1820s with one pipe steam heat.  Five year old Utica boiler.  We had a problem with low GAS pressure (believe it or not) and that was corrected today by the utility by installing a new supply line from the main in the street to the house.  Fun, fun, fun. 

Here's my issue - the system does not appear to be building any steam pressure, so it just runs and runs - it never cycles off.  I've replaced the 30 air gauge with a 15 to see if I can see any pressure changes.  The needle doesn't move.  I've replaced the two 40 year old main vents with Gorton #1s.  When the utility folks were here, their alleged steam guy said that the pressuretrol was working because he tested it.  I think, however, he just tripped the control by hand rather than waiting for pressure.  The pigtail is brand new and clean (it had been clogged when they checked and they broke the pigtail cleaning the old one).  I can't find any leaks with escaping steam on the mains or in the rooms. 

The radiator valves are a mixture of Maid of the Mist and older vents.  None are leaking water but the radiators heat unevenly - sometimes they get hot, sometimes not. I've been trying to diagnose/balance but it's been tough.  

I'd love to get everything venting properly, but I'm not sure that I'm getting pressure throughout the system.  Any ideas as to why I can't build pressure or what I should check next? 

Hap_Hazzard

How is it heating?

The purpose of a heating system is to distribute heat, not build pressure. If you're getting steam to all your radiators without developing any measurable pressure, relax and enjoy the warmth!



By the way, the 30 psi gauge is required by code. A 3 psi gauge might be better for measuring your pressure. A 15 psi gauge doesn't meet either requirement very well.

JStar

Steam

Was the boiler sized to match the connected radiator load?

NJNavigator

Not heating - and dual gauges

It's not heating - or heating unevenly as I noted.  Not all risers/radiators are getting warm and I don't know if that's a venting issue or if the steam just isn't making it out to all parts of the system. Some radiators heat for a while and then go cold and stay that way while the temp in the house drops - even though the boiler keeps running and running.  I thought I had a venting problem but....

Yes, thanks - I know about the code.  I'm a former heating tech, so this is a bit embarrasing with the family. I was unclear - I have two gauges with two different scales.  I added the lower scale gauge.  I couldn't find anything within a 50 mile radius lower than 15 psi or I would have used it. Even most of the plumbing supply houses looked at me as though I had three heads when I said I wanted a more sensitive gauge - even when I reminded them I wanted to run at 2 psi if possible.  I may order something more sensitive from Pexsupply or someone similar on the Net.

NJNavigator

Boiler Size

I believe so, Joe.  It was done by the local NJ utility/gas supplier to replace the old boiler.  I believe it's 195K BTUs driving 13 radiators over three floors - 5, 5, and 3.

JStar

Steam

Was the system ever running well? Has anything changed?

NJNavigator

Changes

Yes - the system worked well in the past.  The radiators farthest from the boiler tended to not heat up that well.  Over time, more and more radiators were going cold even though the boiler was running.  I've checked the level on the radiators and swapped some radiator valves. 

This year, things have been much worse.  The low gas pressure from PSEG was a hassle that threw me off completely. Figured out that issue when the boiler went out completely and wouldn't relight.

I thought I had a venting issue and swapped out for the Gorton #1s.  I noticed that the boiler wasn't kicking off at all.  I checked the pressuretrol settings (0.5 in with 1.0 diff) and spotted the clogged pigtail issue. Even after swapping out the pigtail, it still never cuts out.  Just runs and runs, but no pressure shows on the original gauge or the new one I added.  So that makes sense - no pressure, the pressuretrol won't trip. That's why I'm wondering WHY no pressure even though it's burning away.

The radiators that DO heat up heat up and then gradually go cold and stay that way while the boiler keeps running.  The radiators on the first floor seem to provide more heat.  The ones on the second are struggling.  I just turned off the ones on the third floor (bedrooms we're not using) to see if it makes any difference, since they are fed off the 2nd floor risers.

Hap_Hazzard

Now THAT's a problem.

No heat is bad. Especially today.



Now that your gas service is up to snuff you might want to clock your gas meter to see if you're using enough to get the rated output of your boiler. The easiest way to do this is to time how long it takes the 2 ft³ dial to make a full revolution, then divide 7200 by the number of seconds to give you ft³/hr. Multiply that by 1020 BTU/ft³ to get BTUH (BTU/hr) and compare your result with the input rating in your boiler manual. If you don't have the manual, give us the model number and we'll look it up for you.

JStar

Steam

Can you post pictures of the boiler and near piping? Has the boiler been cleaned and skimmed?

NJNavigator

Boiler

Don't have access to the digital camera today, but will try to post pix.

I was told that the utility cleaned/skimmed the boiler - but who knows. I wasn't present when it was done and they may have thought just blowing out some water from the LWCO and the relief taps was enough.  I haven't found many people that really understand steam heat.

Do you suspect that there's a film hindering steam creation?  Maybe I need to try skimming it myself after the temps are higher than 6 degrees. :-(

JStar

Steam

My first impression is that the boiler piping might not be 100% ideal. But, if it all worked in the past, then it's just as likely that the boiler could use a good cleaning and skimming. Even a little bit of oil and dirt can cause the symptoms that you're having.

Jeff_44

I had a similar issue

a few years ago and finally figured out that I was venting the radiators much more than was necessary. Also, I was given advise on this site to use the same type of vents on all the rads. Once I scaled back the radiator venting, the system was much more even.