Hi. Last night I came home to a few puddles of water on my basement floor.

The pressure relief valve of my Weil McLain VHE furnace (orig to the house – installed 1983) had been dribbling water onto the floor (after it had filled the small bucket I had placed there back in the fal to catch the water). This valve has a set point at 30 psi. I observed the operation of the furnace and ,when it turns on, the pressure sure enough rises to 30 and then the relief valve starts leaking and the gauge levels out at 35 psi. When the furnace shut itself off the pressure decreases and the valve stops leaking. I noticed that the fill valve to the expansion tank was OFF (in effect disconnecting the expansion tank from the system). When I turned this ON, and then observed the furnace operation, the pressure stayed a steady 15-18 psi and the valve did not leak water and it stayed that way all night.

It seems to me that that fill valve to the exansion tank should always be ON (otherwise I’d be removing the tank form the system with it OFF). It seems that the service guy had turned this off the last time he serviced the furnace last year.

This valve had been steadily leaking all winter long (into a bucket I had placed there when I noticed the small amount of leakage then).

So am I correct in saying that that fill valve NEEDS to be ON all the time? There is only one pipe leading into the expansion tank. The tank is not a bladder type (it is an older simpler type of closed tank located betwee the rafters above the furnace).

Thanks to all in advance.

Paul