Utility monitor fuse blown

[cwall59]

I have a 2020 Majestic and I have it hooked up at my house to 50 amp power. I have the gas furnaces set to come on to keep it from getting too cold inside . I went to check it yesterday and though would check the Victron monitor to see how things were . The panel was blank . It the color monitor style , I also have a round Victron battery monitor just below it . The twelve volt fuse panel showed a blown 15 amp fuse marked Utility monitor. I replaced the fuse and the monitor came on and the living room heater came on . It quickly blew the Utility monitor fuse and the living room heater 10 amp fuse . I noticed the thermostat was also blank . I turned the switch off on the living room heater and replaced the Utility monitor fuse again . Start up was the same Victron panel came on and bedroom heater start up and then both fuse blew . Any ideas on what I can check ? I’m not thinking the heater or at fault , could it be the thermostat or something in the Victron Utility monitor? I forgot to mention the round Victron battery monitor is not affected by the blown fuses.

[cwall59]

So I got a chance to do more troubleshooting. I pulled both heater fuses and replaced the 15 amp utility panel fuse and it held. Thermostat came back on as did the Victron color panel . I turned off the heaters at the thermostat and put in a 20 amp fuse for the bedroom heater . I ran it like that for a couple of days. Next I put a 20 amp fuse in for the living room heater. It started up and made a loud noise from the blower and then the noise quieted down . I turned it off and pulled the cover off for the heater. Looks like the blower wheel lost some of the fins . I’m not sure if this was the cause of the fuses blowing or not . I plan on pulling the furnace and checking to see if anything else is damaged before ordering the blower wheel. It’s a plastic blower wheel, there is also a sail switch that could be damaged from the fins coming apart. Kinda strange to have this happen on a heater that’s less than a year old. I guess that’s why it’s a good idea to operate everything to work out the defects.

[ghaynes754]

Lessons learned, buy a new sail switch at the same time you get the new fan blade. The sail switch usually has some unusual bends in the arm and nearly impossible to get the correct shape.

[Burrington]

If the blower wheel was jammed up by the broken plastic pieces and preventing the motor from turning, it could easily blow the fuse. So you have likely found the problem.

Maybe I'm reading this wrong, but just to be sure... Am I reading correctly that you have replaced 15 amp fuses with 20 amp fuses? If so, please change them back to 15 amps immediately! The wire is rated for 15 amps and therefore must be protected by a 15 amp fuse. A 20 amp fuse could allow 20 amps to flow continuously in 15 amp wire, causing it to overheat and start a fire. The 15 amp fuse already popped and saved the blower motor from burning out, and possibly a fire as well (as it was designed to do).

[cwall59]

No the first fuse that was blown was a 15 amp fuse for the Utility Panel . When it blows the thermostat and the Victron color monitor will not work . When I changed it the first time they both came back on and the living room heater also came on because the thermostat was calling for heat . The heater started and both the 15 amp fuse and the 20 amp for the heater blew. I replaced the 15 amp fuse and pulled the 20 for the living room heater. This time the utility panel and thermostat came on . Then the bedroom heater started and immediately the 15 amp and the 20 amp for the bedroom heater blew. I finally got it to not blow fuses but also found the blower wheel had totally come apart on the bottom half of it . Also the sail switch was bent . I picked up a new blower wheel and sail switch yesterday. This is a Suburban SF-42Q heater that is less than one year old . The blower wheel is plastic. Never really figured out what was causing the 15 amp fuse to blow .