AIR TRAPPED IN BRANCH PIPE AFTER MAIN AND SLOW TO BRING STEAM TO RADIATOR

ww

Last year I've added antlers with extra vents on the short and long mains...hoffman and gortons..the large ones..plus used the two smaller ones I had. The mains get hot fast

This is one family house...two floors...oil heat..beckett Af burner.

I do know that from following this site the dead men really knew what they were doing...and know that steam is very low pressure..and less than two lbs of pressure can heat the furthest radiator in the empire state building..

Keep this in mind. I shut the boiler off and put it on while i'm working at location...and doesn't go on and off at night. Since I don't leave the heat on low now overnight maybe this contributes to the problem. I don't know if this is a valid point since only one radiator is a problem.

I put the boiler on and set the aquastat to 200. The boiler heated up. At this time the thermostat was not set to call for heat and I then set the thermostat to call for heat.

I then followed the steam flowing through the mains both the short and long ones...and it moved to the pipes connected to the radiators. It didn't take too long for the pipes to be hot and radiators getting hot as well..except for the first floor far radiator...I checked the pipe from the main going to that radiator and it was hot going all the way up to the basement ceiling..where there are two ninety degree elbows and a couple of nipples going to the radiator above..inches away from the valve above. this radiator is located at the end of the long main run.

I went upsairs and the radiator was ice cold. I closed the valve and disconnected the cold radiator from the valve. The valve was new last year and checked out visually opening and closing. I reopened the valve with the radiator disconnected and no steam was flowing from the valve. I have some theories here. I used a mid range round vent here and also tried a couple of others ranging from hoffman 40 and others.

I looked at pipes leading off mains and the longer one has great pitch..and looks like the other one has pitch too but not as good..but still looks like return condensation would flow..maybe water hanging up in fittings..wondering if i pour some water into valve opening and it backs up there is some sort of pitch problem or something at the elbows below the radiator...obstruction...water...I know there is a little play on the pipe connecting to the radiator..

I don't experience any water hammer.

will have to look at the up and down play as well since the floor has been raised by putting a piece of 3/4 plywood over the floor in the past...that would bring the pipe below up 3/4 of an inch increasing pitch of below pipe and maybe effecting the position of the elbows below.

All radiators were hot in no time at all..except that one. The steam started to come out from that valve in about an hour. I reconnected the radiator and it still took a long time to heat up and it really didn't completely.

Any suggestions?

Abracadabra

Picture of piping around the takeoff from the main to the 1st floor radiator? I had run into a similiar problem like this. 2nd floor radiator at the end of the main was literally sucking the remaining steam away from the 1st floor radiator. Wouldn't get any steam to 1st floor radiator until 2nd floor was filled.

ww

ok..these are the photos...how did things work out with your system?

Abracadabra

Did that first floor radiator ever heat up? What changed between it heating and it not heating?

I bumped up the pressure on the hi/lo fire control so that boiler would generate a bit more pressure. It was at 5/10 oz. before. I bumped it up to 10/15. This was a larger apt. building, not a single family.

What does the aquastat on your system do? What causes the boiler to finish it's cycle?

ww

it was the last one to heat..and not entirely..got hot on bottom and part of right top where pipe was...middle and side still cold.
I still have to experiment with vents on radiators as well as mains..although the mains get hot fast enough.

it seems that whatever vent i try on the radiator...even if i take off the valve and just wait for steam it is the last one to get heat.

the aquastat is for the hot water from the everhot tankless water heater and without a call for heat the boiler goes off when the temperature of water is reached.

if there is a call for heat the honeywell pressuretrol cuts in at .5 lb of pressure and set to cut off at the 1.5 differential setting plus the cut in of .5 which will be 2.

Doesn't get that high and the boiler cuts out when the thermostat calling for heat temperature is satisfied. I set these settings according to what I've read in instructions and what I've seen here.

At one time the radiator vents had high pressure steam coming out and found the pressuretrol was clogged. I took it apart and cleared out the small hole and no high pressure problems after that.

ww

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