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Nikita_blond
Jan 25, 2008, 05:00 PM
Hi
I have a kerr furnace, uses oil but heats hot water and sends it throughout
The house. It has a pipe that goes to the sump pump hole but it seems to be running steady with hot water, enough that steam is gathering in the air. Is this normal something I can do? While trying to Google and find out what I can, came across this site. Thanks

hkstroud
Jan 25, 2008, 05:29 PM
No, this is not normal. The pipe comes from your boiler blow off valve. That is a pressure and temperature release valve. If the temperature or water pressure gets too high this valve releases water. The valve is probably releasing because the water pressure gets too high. This can occur when you have air in the lines. The air heats up and expands more than water and causes the pressure to get to high. You probably have an automatic water feed valve on the water line coming into the boiler. When you have air in the line it expands and creates too much pressure and the release valve open to release the pressure. When the boiler shuts down the air cools and the feeder valve lets in more water. The cycle starts over the next time the boiler fires up again. You need to bleed the air out of the system. Sometimes the release valve does not reseat properly because of sediment in the system. It has been sitting there doing nothing for years, then it opens but does not close completely because some sediment or rust is sitting on the surface of the seat or stem. If the discharge is a steady drip and not periodic opening you may just need to replace the release valve. Be sure to replace with a valve rated for the same temperature and pressure you have now.

NorthernHeat
Jan 26, 2008, 07:13 AM
I'm going to dissagree with hkstroud, the pop off valve is pressure only. Or course if the water gets so hot is begins to turn to steam it will exceed the 30 psi rating and open. You could, have a bad limit control but more probably a faulty pressure reducing valve. Of course this is all assuming this is hot water heat and not a low pressure steam boiler.