riello/mectron 5 M starting then truns off, need help!

Old 02-13-12, 02:27 AM
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riello/mectron 5 M starting then truns off, need help!

Hello all! i have a riello furnace, mectron 5 M. dated 1980. i have learned alot about oil furances, and do oil filters changes, nozzles, cleaning it out myself. okay, so for past few years ( standard oil serviced), our furnace was putting out heat like a suana! and cycling on and off for no reason. the culprit i discovered a moonth ago? a loose black wire, from platform of control box to motor.! he had replaced the triple aquastat with anew one, but not the wires.
ok....i tightened the black wire, and the furnace burned normal. yesterday, over a month later, the furnace turned off. i hit the reset buttton a few times, and it does turn on...but thiers a weird hissing noise for a few seconds, and then it turns off. it does igninte. the problem also, is i replaced the nozzle with a used one. gunna get a new one hopefuly today a delvan .60x85W.
thiers no loose wires, and all 8 wires under control box i tightened. why does my furnace ignitne n turn on, when hitting the red button, then turn off after a few seconds to minutes? its about 42 degrees in the house. thiers plenty of fuel in tank, and a new filter. could it be the nozzle is plugged? thier was quite a bit of black carbon grease smeared form bottom of nozzle spray hole. could it be, the motor? aquastat? (honeywell model)? motor valve perhaps? even few years ago, all i did was replace the nozzle, and it would work with no problems fore a few months...then turn off and ignite for a few minutes, then turn off.
what gives? i wanna do this myself. i am a quick learner, love doing HVAC stuff, thoughh not in the field, and after learning n seeing what the standard oil did..i did more myself than i wanna trust them again. so i dont want a technician to come over. dont have the cash right now...wanna see if thiers something i can do myself!
Old 02-13-12, 02:28 PM
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The "weird hissing noise" makes me suspicious of the burner motor bearings. If you have a clamp on amp meter, check the running amps vs that which is on the motor data plate.

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