water overflow from boiler, hot water system.
#41
12-18-09, 06:36 AM
Update:
With a cold boiler this morning pressure was at about zero.
fired up the boiler, pressure creeped up to about 13 and hung there for a long time, water temp was holding steady at 140.
come back 10 minutes later and temp is still at 140, pressure on the rise to 27.
I let it run to satisfy the thermostat, pressure dropped back to about 25.
rads are bled, water supply is shut off.
One thing I have noticed as well, the boiler is quieter than it was before, have not heard any hammering of late.
Terry
Terry
With a cold boiler this morning pressure was at about zero.
fired up the boiler, pressure creeped up to about 13 and hung there for a long time, water temp was holding steady at 140.
come back 10 minutes later and temp is still at 140, pressure on the rise to 27.
I let it run to satisfy the thermostat, pressure dropped back to about 25.
rads are bled, water supply is shut off.
One thing I have noticed as well, the boiler is quieter than it was before, have not heard any hammering of late.
Terry
Terry
#42
12-18-09, 08:02 AM
Originally Posted by iceracer
My house is 1850 sq ft, 2 story.
Upstairs has 3 rads, downstairs 7, of which 3 are behemoths.
All rads are cast iron.
All the pipes are iron about 1.5 od, once they get away from the boiler and the pipes running through the basement...
Upstairs has 3 rads, downstairs 7, of which 3 are behemoths.
All rads are cast iron.
All the pipes are iron about 1.5 od, once they get away from the boiler and the pipes running through the basement...
What you can do to test this is to use one or more of the large (behemoth) radiators as additional expansion capacity. Note that this usually lowers the output a little , but that may not be an issue.
Need to drain the water out of the radiator(s) and then upon refill do not bleed the air out. Let the air in the top of the rad stay as additional expansion capacity. The rad will fill about 2/3'rds of the way with water, and the top 1/3 will be air.
Now run the system as you normally would. If the pressure stays under control, which I believe it will, then more expansion tank capacity is required. Although, you could leave it with this being provided by the air cushion in the radiator(s).
Or, add additional tanks or one large floor standing tank.
Al.
#43
01-08-10, 07:05 AM
Back again;
I drained water from the system (not sure how to drain the rads, I hope this has the same effect) and did not bleed the rads of air, I tested them and definitely air pressure in them, just gave them a little squirt. I have shut off the water supply line.
Sometimes the pressure reads close to zero when cold and once the call for heat come, the pressure is going to about 27 or so with temps at 175 180.
I just tried turning the pump speed to 2 as it had been on 3, no material change.
Thanks, Terry
I drained water from the system (not sure how to drain the rads, I hope this has the same effect) and did not bleed the rads of air, I tested them and definitely air pressure in them, just gave them a little squirt. I have shut off the water supply line.
Sometimes the pressure reads close to zero when cold and once the call for heat come, the pressure is going to about 27 or so with temps at 175 180.
I just tried turning the pump speed to 2 as it had been on 3, no material change.
Thanks, Terry
#44
01-27-10, 05:44 AM
Here is the final tally.
We changed the pump, the pressure regulator, the expansion tank, the back flow valve.
I kind of un scientifically tested the gauge by filling the boiler to 30 psi and sure enough the pressure relief valve popped.
The shut off valve for the water supply works, because when we changed the regulator etc, it did not leak a drop.
I tried introducing air to the system to act as a cushion for expansion.
The new expansion tank is similar to the old one in size.
The pressure is still hovering around 25 to 30.
Can we add another similar sized tank to the system?
Can you have too much much expansion tank on a system?
I'm at my wits end here.
Thanks, Terry
We changed the pump, the pressure regulator, the expansion tank, the back flow valve.
I kind of un scientifically tested the gauge by filling the boiler to 30 psi and sure enough the pressure relief valve popped.
The shut off valve for the water supply works, because when we changed the regulator etc, it did not leak a drop.
I tried introducing air to the system to act as a cushion for expansion.
The new expansion tank is similar to the old one in size.
The pressure is still hovering around 25 to 30.
Can we add another similar sized tank to the system?
Can you have too much much expansion tank on a system?
I'm at my wits end here.
Thanks, Terry
#45
01-27-10, 07:32 AM
I missed your previous to the last post. To drain the large radiators open the bleeder on them as the system is drained. That will make sure that an air lock is not formed. I am assuming that the piping connections are at the bottom of these radiators.
Can try again by draining the 3 large rad's and not bleeding them. If you can find out how much water is in the system there are sizing charts for required expansion capacity. Figuring the water in the pipes is straight forward. It's the radiators that are more difficult.
You can't have too much expansion capacity. Can put as much on as possible without issues.
Al.
Can try again by draining the 3 large rad's and not bleeding them. If you can find out how much water is in the system there are sizing charts for required expansion capacity. Figuring the water in the pipes is straight forward. It's the radiators that are more difficult.
You can't have too much expansion capacity. Can put as much on as possible without issues.
Al.
