Former 2-pipe steam converted to forced h2o

ThermalJake

My friend has this system with one main runnung around the basement with venturi tees at each loop so that it will suck the water up into the loops. It has a combination of baseboard and cast rads. The system keeps taking on air. You can hear it and you can bleed it at the rads. There is no drop in pressure of the system and it's on a single circulator. There is no real way to close a section because of the pipe set up. I don't think it uses any makeup water, but it keeps taking on air. Is there any way to check for a leak into the firebox? or is there any other ideas.

Thanx

The other Jake

Unknown

pressure

If the system doesn't lose pressure, a leak into the fire won't be it.

A conventional compression tank could be putting it's air into the system....A diaphragm type expansion tank with a small leak could do that too, but for a shorter time before it was out of air.

A conventional circulator seal can let air in if the suction side of the pump goes into vacuum at any point in time...

Air vents at the top of the whole system can let air in if the pressure is marginal (zero at the top of the system, add 1 PSI for every 2.31 feet that your gauge is below that point)

I bet I forgot something else, but there is a start.

Noel

ThermalJake

Now he tells me that he's running 30 lbs of pressure in the system. I think his pressure relief valve might be causing him to take on new water full of oxygen. Thanks for input.