Ok, there’s no appropriate forum for this so I’ll toss it right here in the popular section. Think I need help. Noticed my moms oil fired boiler was at just about zero water pressure when running. When not running it was about 25 psi. I’m guessing that’s not really a good thing. Maybe it’s as easy as a bleeding? She has the cast iron radiators. Anyone know anything about these dirty smelly oily things
im doing some searching. I think it’s ok as is. Very dark in the basement I thought it was closer to zero than it is in the pic. Looks ok for a ranch with a dormer. I’ll leave the post up tho just in case anyone wants to chime in.
It should rise as the temp increases. About 50% iirc. If it goes to zero when cold you have a leak/pressure regulator problem. (You don't want line in pressure) You could have a crappy gauge too I'd only worry about the difference and zero actually being zero. A pressure releaf valve should drip water on the floor if it goes too high. You really shouldn't have to bleed radiators all the time . Although if you have an old converted steam boiler with cast iron pipes and cast iron radiators you can have tiny leaks that may require bleeding radiators more often. These leaks can go undetected at threaded pipe joints and radiator shutoffs as they can dry up at a faster rate than they dribble. edit: same with bladderless expansion tanks, they can dribble/weep and not even leave a stain on the floor under them.
If the gauge reads 0 and 15, I'd guess the gauge is ok. Typically, when gauges fail they either don't move at all or won't go back to 0. Make sure the make-up water line valve is turned on. (You probably did that). Make sure the pressure regulator/fill valve is functioning properly. Drain the expansion tank.
If you have an instant pot pressure cooker it's doing basically the same thing - the pressure increases as the temp goes up raising the boiling point or the transition point from water to steam and cooking faster at a higher temp than a boiling pot would at one atmosphere. If the pressure isn't going up when the temp does you might have a boiler leak which may or may not result water on the floor but the boiler will certainly fire longer than normal trying to heat water at one atmosphere. There's also a safety that should shut the burner off if the pressure in the boiler ever actually gets too low because you really don't want to be trying to heat air in the water channels of the boiler. You're not complaining about having to reset to get it to start so you're probably not going to zero psi.
Think that temp looks right? This isn't a steam boiler is it? I run our 600k BTU hot water "boiler" at work at 170*F on and 195*F off. That equals about 15-18 lbs after its been off for a while, and about 25 lbs when its at temp and running for a few hours...
If the first pic is when he saw/heard the burner fire up it was doing what it was supposed to, raise the temp, especially if a circulator was running. The second pic is probably when or sometime after the burner was told to give it a rest, warm enough. If she's got the old tall cast iron radiators ( I still have a bunch in the garage LOL ) it was easy to tell if they needed bleeding just by putting your hand on them when they were supposed to be hot. If there was air in the top the top of the radiator would be cold when the bottom was hot.
I would say, make sure the pump is running, bleed air out from the radiators, and add water. You can add water up to 20 psi, the relief valve is more than likely set to relieve at 30. There should also be a pressure reducing regulator on the incoming water supply, those are usually set for around 20 psi as well. Sometimes you will have to bleed air out several times over several days before you will get all of the air out. As an HVAC Tech, sometimes customers are blown away by how much time it might take me to bleed the system. And they get upset when there is no parts on their bill, just 3-4 hours of labor, and they say "all he did was bleed air out and add water, I could have done that. " .........yeah, and why didn't you? Because you don't know what you are doing.....that's why you called us.
What do you mean by 'add water' ? I've never seen one that wasn't on all the time. ( I can count on two hands how many boilers I've played with and it's always been to figure out why they haven't started.)
Think you’ve got it. First pic is running. Somewhere between 10-12 lbs. Not close to zero as I thought. Second pic is after running. Higher pressure and higher temp. I assume the gauge and water is picking up the high temps from the water sitting in the boiler. Temp may be a little high. Maybe the circulator should kick on but I’ll leave that for the pros. My concern was the possibility there wasn’t enough water in the system. FWIW she has the flat faced cast iron radiators that are built into the walls. Thanks everyone. That’s why I love this forum. I can get better information here before getting a call back from a service tech. Kudos to all and to all a Merry Christmas!!
The high temp does seem high. Jo asked about pressures though... 250, if thats a water boiler , is too high. 190-195 is usually considered the max.
Some systems fill automatically, some you fill manually. An automatic high point vent is a great addition to any closed loop system.
Usually the system is connected to the house's incoming water supply. Some people don't know to keep the incoming water valve open they close it off thinking that the system is full and it doesn't need more water. Some systems I have worked on have no incoming water supply. So you have to run a house from a sink or spigot somewhere and add water that way. That's what I meant.
I would have thought something like that only existed in history books. If you never ask you never know.
