Newly on my own, need boiler direction

pascack

Label says that’s auto feed. I don’t want to mess with adding freezing water to hot boiler. Boiler off now. Has stopped leaking. 

pascack

It’s in the auto position. The leaking has stopped, for now. This weekend will be bitter cold, so it will leak again. Don’t want to feed freezing water into hot boiler. I’m trying to decide what to do now and who to call. 

JUGHNE

The valve I refer to has the round handle to shut off the water before the fill valve.
Was that usually off or on?

I think that when your pump runs it sucks more water into the system and overfills causing high pressure.
If this is left shut off (round handle) it would prevent more water from being added.
The risk is that if you have a leak in piping then your boiler gets low on water.

Some boiler systems run with the supply valve off (round handle).
If you want to do this, shut the supply off, and when boiler cool drain just a little water out to get the pressure down to about 15.

pascack

This valve? I believe that before he came yesterday from previous pic, it was in this same position. That looks like handle not up before. Yes, I could put it up, but I’m kind of worried to start messing with water pressure, cold water/hot boiler. I should have asked about this valve yesterday. Frustrated I didn’t ask when he was here and he was draining water. I probably should have replaced this, too? The pressure in boiler now(not running) is 12. I’m thinking of calling the company I found out installed this boiler in 1969, and asking if the original owner still there. 

JUGHNE

Leave the handle where it is.

Shut off the valve to the right, the round handle, that shuts off the water to the boiler.
You do not need more water.

See how this works when the boiler is running again.
You want 12-15 PSI when the boiler is cool/cold.

pascack

I guess that would add more water, so not a good idea. Back to drawing board...I didn’t feel confident in diagnosis by company I had here yesterday, so I don’t want to call them again. 

pascack

If this issue has nothing to do with the expansion tank that has been working fine with no issue for 43 years, could it be that the pressure reducing valve(50 years old), is like Jughne suggested, allowing water to be sucked into the boiler on firing?  Is it worth spending the money to replace it to see if that fixes the leaking? Because if it is leaking, installing a second expansion tank as a last ditch effort wouldn’t be necessary. Of course I have no idea how expensive the replacement experiment would be. 

JUGHNE

I think that when your pump runs it may be sucking more water in thru the pressure reducing valve and then the pump is pushing into the boiler adding more pressure to the system.

So if you shut off the water valve with the round handle that is before the pressure reducing valve (PRV) then when the pump runs it can not suck in more water.

Then when the boiler is cooled to about 100 degrees you could safely drain some water out thru the boiler drain so the pressure shows about 12 to 15 PSI.

Then when the boiler fires the pressure might not exceed 30 PSI.

See if this works.

pascack

Thank you. I feel guilty for asking so many questions! I appreciate all the feed back. I have been very worried about the pressure building and upset with myself for not going with my gut when repairman came. Not that it’s bad to get a new part, but I didn’t think I needed it. 
Good news is that I talked to a long time installer/fixer and he asked for pics. He feels that the capped off pipe on the expansion tank can be opened, and system drained. That’s first step, at least. He put my mind at ease about way too much pressure, because he said my old boiler is rated much higher than 30-35psi that triggers my water run off. Youngplumber, I did check for contractors outside of Chicago. Nothing really close and with the temps so very low, I felt no one would want to travel very far if people nearby without heat. I have heat! I’m crossing my fingers it stays that way. Jughne. You’re the best! So thoughtful/helpful. It could be that the PRV valve is also bad. Your theory is correct. But I’d really like to check expansion tank, too. I’m also a bit worried about turning off the water to that PRV valve because I don’t want to make a mistake and ruin something. Also, I’m sorry if this is a stupid question. But if one drains water out of boiler to reduce pressure, then if later the automatic feed gets turned back on, wouldn’t more water be added and then it’s the same problem? Or if you turn off the automatic feed, how would you know if you needed more water? 

JUGHNE

You would know you need more water if the pressure drops to perhaps 12 psi.
It takes very little water to raise the pressure back up.

pascack

Ok. I never fully appreciated how well my system worked for so long without problems! Thanks. I’m hoping Monday will get things working properly!

pascack

Pleased to share that boiler not leaking! Second company came, opened the cap on second floor old expansion tank, drained the radiators below expansion tank. Not sure sequence of when he recapped pipe at expansion tank, but at some point he did. Water was replaced. Pressure wasn’t right at first. I bled radiators. Though little air escaped from radiators, that brought pressure to normal range. Two days and still fine with no water escaping from relief valve. There is a slight minor knocking every once in a while, but before when relief valve leaking/high pressure, there were more loud knocks. Thanks for all the helpful comments, which really helped me understand the issue and kept me from putting in an unnecessary 2nd expansion tank.