Need help with my hissing air vents

briandonahue1800

I have a 1 pipe system and cant get my radiators to stop hissing and losing steam, needing to constantly re fill my boiler. I replaced all the air vents, replaced the 2 main vents which are at the end of the dry return above the boiler, raised them up a bit, and it did nothing. I dialed down the pressuretrol all the way down and the pressure gauge is still climbing to 3-4 psi when the boilers running. I havent cleaned out the pig tail yet but i was assuming that wasnt the issue since the gauge is reading pressure. Where do i go from here?

Captain Who

If the pigtail is clogged the pressuretrol can't see the pressure. If it can't see the pressure it can't cut out the power to the gas valve.

If you are using the 30 psi gauge that is there for code compliance, you might not be getting a true reading since they quite often clog if they are the internal syphon type mounted right on the boiler without a pigtail of it's own. Are you saying it is on the same pigtail as the pressuretrol? If they clog they can be reading temperature more than pressure and that may be a false reading. It could be higher than 3 psi., and that would cause lots of vents to hiss that can't handle the pressure.

briandonahue1800

thanks for the response man, yeah so its a 0-30 pressure gauge at the end of the pig tail off of the T for the honeywell pressuretrol

Jamie Hall

"Dialed all the way down" means? the index if it is a single scale set at about 0.6 psig? If so, my guess is that the pigtail is clogged. As has been said, the 0 to 30 gauge is useless… but required by your insurance.

dabrakeman

Can you show us a picture of your pressuretrol? If it is the gray box additive type there may be some room to further adjust it. Just do make sure the pigtail is clean first and you will be wanting to get a 0-3 or 0-5 psi gage. This is necessary for the fine tuning of the pressuretrol.

patrykrebisz

at 3-4psi, your should have steam engine train in your bedroom. 3-4 psi is a lot. even at 2psi, proverbial max of residential steam, you will get loud hissing.

1. get yourself low pressure 0-5 or 0-3psi gauge and mount it as T right next to pressuretrol. this will allow you to see the REAL pressure in your system (as you are there clean the pigtail).
2. make sure your pressuretrol is set correctly. on the "gray box" cut in should be 0.5psi and differential inside the box should be set to 1. on the one with plastic cover, your main should be set to 1.5-2psi and your differential to around 1-1.5. (if you have installed your low pressure gauge, you will get to see if your pressuretrol is operating correctly shuting off the boiler when it s supposed to = most likely yours isnt).
3. figure out why you build up pressure so quickly. your mains, even though vented, probably could use more venting. install aditional main vents.

neilc

does that gage settle back down to zero(0), and or rest on its pin when the boiler stops firing?

if so I'ld be looking closer at the Ptrol, show us that picture of the scale face,