Air vent ID and pressuretrol piping

71403

Last cold snap got call from inlaws that "a lot of banging noises" were coming from the basement - found pressuretrol set at 2psi but still not opening when the gauge was at 4psi and rising. Finally opened when I gave it a light tap. Picked up a replacement and set it to .5 cut in / 1 psi cut out and it works consistently. Tested the LWCO and it's operational.

Does the piping near it look right? Almost every one I've seen has a 180deg pigtail and the control above the boiler waterline.

There is a main to each side of the house, 20' and 25' long with an air vent at the elbow where it ends and turns down to the return. One vent is a "Dole 3A" which is plugged solid. The other can make out " ______ - lite No. 255", it too
was clogged but was able to clean it out.

Thoughts on what to replace them with?

From what I read here just by being 1/8" port they're both far too small. Don't want to mess with getting the reducing bushings out of the elbows in middle of heating season.

Fred

If you have about 8" above the mains, you can put a 1/8" close nipple in the tapping, and a 1/8" to 1/2" coupling on it and install a Gorton #2 on each main. That should be all you need for those mains.
Before you buy a new Pressuretrol, make sure the pigtail (looped pipe and the Tee that the Pressuretrol is mounted on are not clogged with gunk. You say the gauge reads pressure so the pigtail is likely open but the Tee may not be. Also make sure the tiny port in the bottom of the Pressuretrol (in the hex nut that screws onto the nipple) is not plugged.
If those are open, try this procedure to recalibrate the Pressuretrol:
Inside the Pressuretrol, right below the micro switch, there is a pivot arm. At the end of that arm you will see a screw pin that is activated by the diaphragm at the bottom of the Pressuretrol. If you look very carefully at that screw pin, you will see it actually has a tiny (I mean tiny) hex head on it. It takes a .050 hex wrench and you can turn it clockwise (Towards the bottom of the Pressuretrol to decrease the Cut-out pressure or counter clockwise to increase the cut-out pressure (which none of us want to do but who knows, your Pressuretrol may be really screwed up!). Turn the power to the unit off first. You may find the first attempt to turn that screw a little bit stubborn (relatively speaking) because it has some Locktite on it but it does turn. Don't turn too much, a fraction of a turn goes a long way towards getting it adjusted where you want it (maybe 1/32 inch turn to start with). You may need to play with it to get it exactly where you want cut out to be.