small leak stain around boiler base?

brooklyngreg

I have a oil burner steam system for a 2 family house. Last month the water began pushing up into the radiators because the water level "somehow" got too high and cut off the steam. It made a water stain at the base at that time. We had our oil company come in and replaced the shut off valve to where the hot water use to come out of the system for household use. Since then we shut off that valve and only use the hot water tank and NOT the boiler for hot water. Today a month later after the boiler been working fine I found a 8 inch around stain at the base of the boiler like it leak over night when the system wasn't running because it was a warm evening. Is this 8 water stain going to reoccur until its a big problem, can I use stop leak? Can I finish this heating season out like this?

billtwocase

need pics

The leak could be anything, and we would rather narrow it down for you. Does it have a tankless coil that is no longer in use?

brooklyngreg

coil not in use

Thanks a million for responding. We do not use the coil for hot water any more and the coil is inside the tank but the valve is turned off sto it, so no water can enter. Not sur ewhy there would suddenly be a small water stain, the system did cool off all night because it was warm outside.

Its been working fine giving heat only and the furnace only comes one 2- 3X a day and evening.

Paul48

Cold supply

is shut off. How about water under pressure coming back from the water heater?Trace the piping to the heater, and see if it's possible.

brooklyngreg

water trikling down right footing under boiler

there still is a cold water feed to the circulation pump, the trickling stopped last night and still has still not re-occurred. I have a feeling when the unit gets cold from less use it triggered the leak.