SUBURBAN SF-30 TO SF-35 FURNACE UPGRADE

[Sykes]

Can I replace a SF-30 30000 BTU Suburban furnace with a SF-35 35000 BTU unit?

My SF-30 shook extremely last night and shutdown. Now cool air blows with no heat. Since its 5 years old, I am replacing and will repair this unit as a backup. As I already have 4 interior cabin vents, can I upgrade to a SF-35? The unit is running on a 20 amp fuse and this seems like a better option for our 650 square foot space. The Suburban installation guide specs (except for vent specs) are the same for both units. Thanks. John

 

[Gary RV_Wizard]

Should be no problem, but I can't see any good reason for replacing a 5 year old furnace rather than fixing it. A "shake" sounds like a busted fan.

You gain 5000 btus with the bigger furnace. Is that what you are looking for?

 

[Sykes]

I would like to fix; but we do need a second unit as these have gone out several times now in the middle of winter - and usually during blizzards. The 2 am shake last night shook the whole RV. Now the furnace runs cold air and then shuts off after a few minutes. From a troubleshooting chart, looks like it could be the motor mount (there is play); the blower motor shaft or blower wheel. The fan does sound perfect running cold air before shutting off after a few minutes: would that be the sail switch? Most likely something was shaken to dysfunction - it could take some time to troubleshoot this one. Any ideas will bring this unit back. Thanks.

On a new furnace: the 5000 extra BTUs would be welcome.