Oil on the boiler room floor

[Sandy Pittendrigh]

I have a Prestige Triangle Tube boiler, going on 5 years old, feeding into a network of hot water radiators. Southwest Montana. Five years old. So far flawless performance. Until now.

Late today I noticed a large pool of thick clear oil on the boiler room floor. It's not clear where the oil came from but the there is a copper pressure relieve valve on the top of the boiler, feeding into an open-ended copper pipe that points down almost all the way to the floor.

The inside of that pressure overflow relief pipe feels wet with oil. So this must be coming from within the boiler somehow. This does not sound good.

I have not yet been able to reach my plumber. After 5 years I'm not sure he is still in town. Good plumber. But for all I know he moved to Seattle. Or Timbuktu.

If I cannot reach him tomorrow I'll look for another plumber.

In the meantime what is your guess (anybody)? How serious is this? How and why does thick heavy oil squirt out through a pressure relief valve?

 

[Smooky]

What type of fuel does it use? Is it an oil fired boiler?

 

[Sponsor]

 

[Dana]

This is a gas or propane fired modulating condensing boiler. SFAIK it does not use oil anywhere inside the boiler itself.

Sometimes in cold climates heating systems will get filled with a glycol/water mix to avoid damage in case of freeze up, and it's at least possible that it spit up some glycol during an over pressure-condition. But on a properly designed properly filled system that over-pressure condition should not be happening.

There is almost always a pressure gauge on the system somewhere- check it, both when the system it tepid/idling, and when the boiler is firing. It should be 12-15psi when tepid, and under 25 psi when fully hot on the coldest day of the year. If the pressure is high when cold, it's like the that the system fill-valve is over-filling the system with bleed-by leakage. If the pressure is rising quickly during firing, it's likely that the expansion tank has lost it's pre-charge or it's shot. Tap on the side of the expansion tank in a few places- one half (the side with the air charge) should ring, the other half will thud. If it's all thud, it either needs re-charging or replacement.