We have a (fairly) new house going on it's second winter. During the middle of the 1st winter, the Peerless oil fired boiler w/Beckett burner shut down. Plumbers found cause to be clogging of the oil tank filter by a black slimy substance. Replaced filter and all ran ok. Now, approximately 8 mos later we've been complaining about the "unit" running loud and rumbling to a stop. Plumbers didn't make it out before the boiler blew off it's exhaust vent and filled the room with a black smoke. We shut it down for a couple of hours and then it purred like a kitten for a bit. Again turned it off til plumbers arrived the next morning. Upon checking the oil filter they again found the same black slimy substance.

The oil company insists that the oil delivered is not an issue but may be forming bacteria if the room is too warm. Indeed the oil tank is co-located in the same 10 x 10 room. The first winter was full of complaints that the utility room was too hot. After an outside vent was installed on the Peerless, it was a little better. There are radiant tubes that run and terminate in this room, so they may be contributing to some of the heat. The unit is again starting to run loud.

I personally placed a call to the Peerless rep to schedule a call with the plumber and myelf. He says he's never heard of bacteria in oil..

A few questions come to mind:
1) Is there such a thing as bacteria forming in oil because the room is too warm ?
2) Will adding an "additive" to the oil help to prevent this bacteria ?
3) How often should an oil tank filter be changed; most likely more often if getting dirty quickly.
4) What might cause the Peerless to run loud, rumble to a stop ?

thanks !
From a true beginner