New PSGO installation, Heat is slow to 1 of 2 system risers

Dannyt&c

I installed a WM-psgo-6 in the summer and recently have a complaint about one side of the building with a lack of heat. Turns out that the steam on the back system riser on the header seems to stop at one of the 3" elbows right near the boiler, and it takes a long time for it to move, while the steam is flying down the front system riser and heating nicely, satisfying the thermostat located on that side of the building. In locating the old vent and replacing it with a hoffman #75 main vent, we thought we had it, but it didn't help. Removing the vent also didn't help. It is located on the end of the line. Don't know what to do. I have some pics. Hope its not to hard to see.

BobC

Just a thought

Did that side heat fine initially and then stop working? Do you know for sure this wasn't an issue before the new boiler went in?.



 Have you checked the piping with a level to be sure you don't have a low spot thats filling with water? With a main it's not likely but old houses do settle.



Bob

jpf321

one hoffman is inadequate

that 3" pipe .. at least near the boiler .. you need some mighty venting on that sized pipe. for example 65ft of 4" pipe would be adequately vented by 4pcs of Gorton #2. what is the actual diameter of the pipe and how long is it?



as well, all mains should be insulated with at least 1" thick fiberglass. (and near boiler piping as well)



what is the venting like on the other main? I assume this is a 1-pipe steam system? what is the rad venting like on the good main vs. the bad?



are all the radiator valve FULLY open on the bad side? are all rads slightly pitched toward the inlet valve?



as BobC mentioned, do you have any sagging pipes with pooling water? is this a counterflow or parallel flow system?



can you mark one of your pics with where the steam seems to stop? what happens if you let the boiler run a very long time? does it cycle on pressure or does the steam eventually move down the bad side? (after the good side is completely full and all rad vents are hot andclosed)



i know many more questions than answers, but this is how we diagnose.

Dannyt&c

going back to recheck

thanks for your replies, I will get back to the job to check on all those things that were pointed out and then return here.

Dan

BobC

Another thought

They occur so rarely these days.



Try turning off all the radiators on the good main, or turn the vents upside down - assuming they all have floats. That will force any steam into the cold main. See if that side gets hot and note any water hammer; if you can localize it you may find your problem.



Bob

Dannyt&c

contaminated water

Returning to the job today and able to watch it run a heating cycle, we watched it go off on low water. So after draining it and adding "steam clean" (my prefered boiler treatment) the water stayed steady and heated both system risers quickly.

We then checked all the radiators to see how they were heating and found 3 with bad vents. The rest heated nicely

We decided to return and drain it again to be on the safe side. (no need to skim with "steam clean".) So... good for now, we'll see what happens down the road.

I went back with a list of things you guys gave me.

Thanks for your interest and time.

Dannyt&c