What The ....... ???

Bob Schultz

Well, I had the opportunity to see this job again, because it's still going above 30 lbs and lifting the relief valve. Apparently turning the pump around didn't fix it.
It's not a Monoflo system. Just a basic split loop, with one 1 inch supply, and three 3/4 inch returns. No check valves, and the PRV is working like a charm. Out of desperation, I changed the 30 year old Extrol expansion tank. It "felt" waterlogged, but didn't sound like it when I tapped both sides of the diaphragm. I guess we'll see if they call back tomorrow.
30 to 40 year old "General Automatic" Model LG-6 boiler, apparently designed to pump away from the bottom, which looks like a return.

Bob Schultz_2

Circulator installed \"backwards\" on purpose ?

Kind of a long story, but bear with me here.
Found a siezed up circulator on a 50 year old "General" boiler. Circulator was mounted on the return side, but pumping out of the boiler, to the system.
Being the professional that I am, I installed the new circulator in the same place, but pumping into the boiler return, like it should be. Right ? Wrong.
Started up the system, and as the water heated, the pressure went to 30 lbs and blew the relief. I checked the expansion tank and it was fine, so I bled down the pressure to 12 lbs, removed air, and started it again. Pressure went to 30 lbs, and blew the relief.
I figured it probably didn't do that until I changed the pump, so I turned it around to pump out of the return, not feeling right about it.
Started it up, water heated, pipes got hot, and the pressure stayed at about 15 lbs.
I don't get it.

GW

wow

there must be some reason why the pressure increased. Was there a flow check on it? The answer must be right there.. somewhere,,,

Gary

Dave Yates (PAH)

tugging my ear

Sounds like an Edwards boiler. They pumped away from the bottom, which looks like a return, but isn't. My first one, about 35 years ago, bit me exactly the same way(G).

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Ted_9

boiler

Do you think the bottom tapping goes straight to the top of the boiler, thus creating too much pressure near the relief???

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Bob Schultz_2

Maybe it's a Monoflo system. I couldn't see the piping because of a drywalled ceiling, but there were three 3/4 inch "supplies" and one 1 inch "return". If it were a monoflo, there wouldn't be much circulation if it were pumped backwards, and the pressure would increase as the water got hot.
The boiler was definitely an old "General" brand, nothing unusual. I've seen hundreds of them.

Bob Schultz_2

It was a "General", but maybe they did the same thing. Pretty strange.