While researching WM gas boilers for my oil-gas conversion project I noticed that Weil-McLain doesn't like homeowners to install there own boilers. This is probably to protect themselves if some one screws-up. But now i am wondering if I have a problem with the system I installed is WM going honor the warranty. I understand I would have to deal with the plumbing supply i bought the system, from but I imagine it would still be WM making the decision.

I need to spec the vent pipe for a new Biasi B10 oil burner. This is a three pass, low stack temperature (350F gross) oil fired boiler and is even rated for direct venting. I'm going to vent it into the existing tile lined chimney and hope for the best on condensation problems with the low stack temp. I assume because of the low stack temperature all I need is Type B Gas Vent pipe. Or am I wrong and should I use the oil burner rated UL103 1700F Class A pipe? Seems like overkill. The original 35 year old boiler used Type B Gas Vent pipe and I don't recall seeing any Class A pipe used on oil boiler to chimney installation I've seen.