steam heat, presure building

phil_7

I bought my first house at 22years old from family everytime a problem evolves family swares it never happened before I moved in. anyway the presure builds to 5 psi on a american standard steam boiler, feeding convectors not sun rads or radiators. I replaced the t stat and set the anticipator to longest cycle.I also plugged one of the cast iron burner tubes to down fire the boiler. From a dead start it runs longer as expected but still builds psi. I set the presuretroll so it would cutin at 1/2 and off at 3psi. I need help! the vents are all new and I also replaced main vents, boiler is clean and returns are clean . there is no hammering whatsoever.what is the most efficiant way to fix my delema? should I pull another burner rack ? I cant close down on gas presure because there is no regulator on the millivolt gas valve. Also don't want to put a vapor presuretroll in because of the expense on a 20 year old boiler.

Jnash

steam problems

I have been having trouble balancing a system (steam) in a very old house in the community. The house is very formal and the living room is the farthest from the boiler. It was getting very little heat to the radiators that are built into the walls so i raised the pressure from 1.5 psi to 2.5 -3.0 psi now the kitchen end (nearest the boiler is quite warm, Should i return the pressure to where it was? Is that a correct pressure to run a residential system at? I have been gradually working through the entire house replacing steam traps and valves over the past couple years, however never have been able to get the living room up to temperature that is comfortable.

don_9

Good morning all.Phil so are you saying the boiler is
oversize? I would think if that was the case you would have
hammering at mid cycle.

May want to take a look at the vents and see if they are size properly.I have never seen a steam boiler build that kind of pressure on a home with out making some type of noise,be it air or a water hammer.

If its oversize then it time to throw in the towel and installed a boiler that is closer to the connected load.

Dale

Pressure

I think you may have a clogged pigtail to the pressuretrol. Pigtails are pretty cheap so I would replace it. Do you know if your gauge is accurate? The old pa404a's aren't all that accurate at low pressure but will work if you test them against an accurate gauge. I do this with compressed air on the bench and can usually get them close. if it won't work on the bench get a new one.

David Efflandt

Pressure gauge may not be accurate

Even after I checked my pigtail and set the pressuretrol as low as it goes, my gauge still went way up (and did not go down when pressure cycling or until long after boiler shut off). The gauge was on an extended totally blocked snubber, so it was just reading trapped air pressure expanding when hot.

Since most pressure gauges do not even register below 2 psi, I now have a metal pressure/vacuum gauge which shows everything working properly (cut-off before it reaches 2 psi and cut-in before it drops to zero).

scrook_2

steam problems

Run the pressure as low as possible, e.g. ON about 0.5 psi, OFF about 1 to 1.5 psi, but less than 2 psi.

Do you have a working main vent (like a radiator vent but bigger) in the cellar on a tee near or at the end of the steam main that feeds the distant LR? Do you have them at the end of the other mains (assuming you have more than one main)? You want to *rapidly* vent air out of the main so steam gets to the end, then the radiator should heat (assuming it's vent is working too). Also, is the valve on the radiator open? Does the riser to the radiator get hot quickly? Does the radiator get hot at all (steam pipe end only)?