Pressure issue

Shadowdoc

Sorry if this seems long-winded but I’ve learned that more information is better than less information.

As you can see by the pictures I’ve tried to I provide as much info as possible. The system it’s for a two-story building which is my residence, a former church fellowship building/hall. All baseboard heating, the lower floor/zone is at the same level as the boiler and the baseboards are actually lower than the pressure or fill valve by a few feet. There is one floor/zone above the boiler with baseboards. 

I’ve noticed that the pressure drops to just below 10 after a few days. I use the The feed valve to raise the pressure and then turn it off. I turn it off because it appears that the auto supply valve (pic) never shuts off and the pressure kept going up and the previous owners just left it open which allowed the PRV to open and this just went on as a repetitive cycle.

I’ve also noticed occasionally small amount of water doming at the opening of the air release valve (pic).

Expansion tanks (pic) apparently were last replaced in 1998 and one of them seems to be waterlogged as by the sound when tapping.

I guess my question would be since I can isolate the outflow and the inflow into the boiler through shut off valves, would it make sense to cool down the boiler relieve the pressure after shutting off and isolating the boiler and then replacing the 2 expansion tanks, the air pressure valve and the auto supply valve?

If the loss of pressure is from a small leak which is very possible, I would like to keep the auto supply valve on as long as it’s working properly and shuts off when the appropriate pressure 12 to 15 psi is reached. 

Jamie Hall

Have you checked those two expansion tanks for air pressure? That blue cap on the top conceals a Schrader valve, and you can use a tire gauge to find out what air pressure (you hope!) is in the tank. If you get 12 to 15 psi it's probably good. If you get low -- or it goes to 0 very fast (phoop...) that's not good. Nor is water. If it goes to zero or is low, try a bicycle pump or some such and see if you can get pressure into it.

No one did you any favourrs with that installation. There should have been shutoff valves on them...

That pressure reducing valve looks very tired. The theory is that they should shut off when they reach the set pressure... a new one probably will.

Ironman

I’d change the fill valve to a Caleffi with a back flow preventer.

Technically, there’s nothing wrong with using two expansion tanks if they’re connected at the same point, but IDK why people do that. I’d use one that’s properly sized. AmtroL has a tank sizer on their site.

You need to set the air charge to 15 psi BEFORE connecting the tank to the system and also set the fill valve to that pressure. 

One of the flow check valves is leaking as well as the air vent on top of the boiler. Those leaks, as well as any others, need to be fixed.

Shadowdoc

Zero pressure. Just checked. ☹️

One had no pressure, the one I thought was waterlogged spit at me. 

EBEBRATT-Ed

@Shadowdoc

B careful with a waterlogged tank, very heavy