Last night when I kicked the thermostat on I heard some gurgling in the pipes and so I figured I had some air in there. I grabbed my trusty radiator key and bucket and went to bleed them off. When I got there, it seemed like boiler pressure was low. I checked in the basement and sure enough it was under ten pounds. I looked at the device I felt should be maintaining the pressure, which is this:



Now I thought this is the correct position to be maintaining me at 20lbs. But then I thought, maybe I don't know how this thing works. So, I tripped it into its other position which is this:



And then I went up stairs. Boiler pressure had improved. I bleed out the radiators an went back to my desk. An hour later we were eating supper. I was hearing this odd noise above the bleating of the children. Sort of a whoosh... <thunk>. I went down in the basement. Luckily there was only about three inches of water on the floor. The boiler was blowing its pressure valve, (whoosh) and then after a few second it would stop and water hammer <thunk>.

So, what is this valve? Isn't it suppose to keep the pressure up? The upright position is water constantly on, right? I know this much now.

--ja

You really need to ask your pals FIRST before you touch things you shouldn't





The lever is for direct pressure to power flush. It may be adjusted but better replaced. Call Steve! or adjust manually as below

www.bellgossett.com/literature/files/1195.pdf

I read the pdf just now weird they say 12 psi I been working on hot water heat for 25 years and with boiler in bsement i adjust that valve to 20 psi when the system is hot it is how i was trained when i went to boiler school at weil mcaine on the top of that valve is screw slot losen the nut adust the pressure with screw driver stay about 20 psi with hot system you be fine 30 psi with blow the pressure relife valve

nice to see another good boiler guy hang around

but just because you did it for 30 years - don't make it right

you only need enough pressure to lift the energy to the highest radiation - if you did pressure test that point -- 3 psi would be enough at the hi point and what ever pressure was then down at the lowest or at the fill regulator would be the correct system pressure for THAT infrastructure.

Setting all systems to say 20 -- is like using the same boiler in every heat load with out doing a heat loss calculation to find the correct size boiler. Most of the time it would be too big and sometimes it would be right and maybe it would be too small in a house like our Mayor lives in.

well where i live is collage town some of the hot water boilers i work on feed 150 to 200 rooms some of them are just single family home. the pressure of the water flow has nothing to do with the size of the boiler install. yes you have to do a heat loss calculation on the home to figure how the big the boiler is and how much raditor goe in each room. but you need good flow to carry the heat.

wingman1776 wrote:


Agreed

Fault tolerant flow based on heat loss of the load combined with correct pressure.

Just ask Sidecar what happened when he incorrectly adjusted pressure on his new radiant

jabbott wrote:


It must hurt like hell to have to take advice from a red meat eater like me. But since most libs expect to be bailed out by others -- I guess I am your daddy

Since you asked about your system pressure regulator - and I should add it must include a back flow preventer - YOU haven't gotten back to your public

I should point out that this part of your system is very important to the health of that way too expensive new Mod-Com boiler you have so --- did you replace it like a good forum Mayor?

Kind Regards
Sting

First I need to be in the same state as my boiler. I am in St. Paul for three more days. But then I should be home this weekend. I will be taking a look at it if my wife hasn't put too many things on my project list.

So far there is only: 1. Help number two son build a pinewood derby car.

--ja

that is a pressure reducing valve, set at 12 psi from factory, that works great for most homes. you only need enough pressure to raise water from basement to top
floor. .433 psi per foot. the lever is for manual fill, the problem with prv is they don't get used enough. so when they do they keep feeding and lift your pressure relief valve, 30 psi most of the time. I personnel like a manual valve, keeps you in touch with your boiler. plus if a pipe breaks when you are gone, you don't come home to a flooded house.