relief valve

Randy Bultmann

Had to do the first fire up of the season, I went around to all the cast iron rads and checked for air. I went around the first floor, no air (great!)then upstairs (2nd story) and nothing came out. No water, no air (crap). So I go to the basement and look and see that I have around 12# pressure in the system. So I add water and bring it up to 20#. I bleed all the rads, and then bring the boiler down to 15#. I then checked the upstairs rads again and yes there is water and no air. I fire up the system, and since it was 60d in the house it took a while to start warming up. I checked on it in 20 min and noticed that the pressure gauge read 20#. Checked on it again (about 20 min), 40#. I then got busy and forgot about it for an hour, When I went back downstairs there was wet concrete where the relief valve had shot water. I shut off the burners and seen that there was now 20# pressure in the system. Now I am assuming that once the system cools, I will not have enough pressure for the upstairs rads. Especially if it goes below 12#. I have read that maybe the expansion tank may be the problem, but I have never messed with it. It is a long cylinder that is above the boiler near the ceiling of the basement. If it is "waterlogged" would that cause my problem? I've never had this problem before. Thanks

Dale

exp tank

The expansion tank would be the usual suspect, since you only have a 2 story house #12 cold should be plenty. Dribble water out of the boiler drain until the gauge is at 12#. Then, if the system was piped correctly, close the valve between the tank and the boiler. Then, open the drain valve on the tank and if there is the correct fitting at the other end, the small nut to let air in. If only the drain valve you can force air in with an air compressor blow gun, or a small plastic tube or whatever you want to get air to the top of the tank so it isn't vacuum locked, when the tank is completely MT shut the outlet valve, open the tank supply valve and you will have about 1/2 air which usually lasts for many years. Bring the boiler pressure up to 12# again and you may have fixed your problem. If you call a pro for this watch how he does it, getting the air out of the steel tank is the trick. Good luck

Geno_15

old indian trick

kimosabi-- if exp tank have only drain valve and no vacumm breaker, put hose on boiler drain, shut off boiler and water supply and system to boiler if possible, drain boiler till presure zero, open valve on exp tank to let air in, avoid completely draining tank by listening careful and checking side of tank with small wrench, where there is water it "tinks", where there is air it "tings" or sounds hollow, closem valves, fill system to 12#, that how red man do it.