My just-under-3-year-old FWH single-zone system (that some on this forum assisted me in choosing) recently developed a leaking pressure relief valve. The technician could find nothing obviously wrong. He zeroed out the pressure on the system, checked the #60 Extrol tank, which had been installed in late 2012,(6 months after the original installation of the system, replacing the #30 Extrol tank). Everything seemed OK, but it still ran up to 30 PSI, and leaked. It is an old home, about 2800 SF/2-story, converted steam system with huge radiators, huge cast iron piping, much water volume. Six months after the installation, at the new heating season, the #30 was blowing the PRV, so they put in the #60. It ran at 25-lbs, but it did the trick until recently. Just for fun today, when he could find nothing glaringly wrong, the technician decided to try a new expansion tank. When he was taking the old one off after depressurizing it, he slowly unscrewed it, holding it there momentarily as it more-or-less finished leaking. As he finished unscrewing it, and then while slowly lowering it, it suddenly and instantly sprayed a fair amount of highly-pressurized water for 3 or 4 seconds, like a gusher, sending a stream of water to the ceiling, as well as getting fairly soaked himself. He was shocked and indicated that that had never happened before. The new tank (HTX #60) seems to be holding at 25-lbs at full operating temperature—so I hope the problem is solved. Does anyone have any opinions on what happened, and if the problem is likely fixed? I have been charged $95- for the “diagnostic fee” and $133- for a “Misc. Repair”. $228- total. Have I been mis-treated? The Extrol tanks seem to have a 5-year limited warranty, but it is unclear how that all works. Thanks.

Hi all, been a few years since I have had any issues with this system. Got it cleaned and service last June. About a month ago noticed the fuel smell occasionally when I passed the basement stairs. Got worse last week. So I pulled the F3's cover to check for leaks. No found, pulled nozzle assembly. Gunked and sooted up? Did not expect that as when this system gets the right tune it soots very little and uses oil sparingly. Cleaned it all up. Changed to a brand new Delavan .60 60W nozzle as per F3/Viessman manual. A ongoing issue I do have even with a unfinished basement is air supply for burner. So I left the basement window open about 1 1/2 and all was fine for a few days. Oil smell returned. So I pulled out nozzle assembly again. Still clean, little to no soot. BUT wet below nozzle. It appears to be drooling after it shuts down. BIG ? What stops the oil in the delivery tube from dripping out the nozzle when burner shuts down? Naive me thought the nozzle was closed when under no pressure to keep it from drooling. Just to test, I cleaned the end of the oil tube and puckered up and blew into it. Oil spray out real easy? Tks for your help Pete