Atwood 8535 blowing fuses

[good2eat]

I have an Atwood 8535 -IV- DVLP. It turns on and the blower motor runs like it should, then the ignitor lights fire. It runs for about 5 seconds and then blows the fuse so somewhere the voltage is building or something is grounding that blows the fuse.

I recently replaced the blower motor as the bearing went out and then replaced the board and the on/off switch that is located in the furnace frame. I don't find any bare wires getting grounded.

Only thing I can think os is the motors winding is bad?

Suggestions?

[dougrainer]

drsteve wrote:

RJsfishin wrote:
A bit larger fuse ?? Naw, too simple to try that.

Always a bad idea.

I hope he was joking. 45 years ago, when I lived in the LA area I dated a girl whose father was a Transmission specialist for a Pontiac Dealership. He told me about a Technician at the shop that when the new Pontiac kept blowing the Interior dome light fuse, the Tech wrapped the fuse in foil and installed it, It burnt the headliner and partial of the dash when the fuse could not open the circuit. THAT story always stayed with me thruout my career as an RV Tech, about what can happen when you go around safety items. Doug

[drsteve]

RJsfishin wrote:
A bit larger fuse ?? Naw, too simple to try that.

Always a bad idea.

[BFL13]

Good follow-up. Doug had it right.

[good2eat]

Was the white wire going to the high temp limiter, had gotten pinched and was arcing to the grounded chassy

[RJsfishin]

BFL13 wrote:
The additional 0.5 amps when the burner is lit, isn't much to blow a fuse unless it is the straw that broke the camel's back. Or that 0.5 goes way higher due to a loose connection or something.

One thing as suggested in another thread, was to disconnect the 12v wire at the furnace that goes to the fuse panel. Now use a portable 12v charger or jumper cables from a battery to power the furnace by itself and see if that still happens.

If not then at the fuse panel, is there anything else sharing that fuse with the furnace that could be adding amps?

With so many replaced parts, that leaves many opportunities for something to be not put back together right.

Repeat !!
A bit larger fuse ?? Naw, too simple to try that

[BFL13]

The additional 0.5 amps when the burner is lit, isn't much to blow a fuse unless it is the straw that broke the camel's back. Or that 0.5 goes way higher due to a loose connection or something.

One thing as suggested in another thread, was to disconnect the 12v wire at the furnace that goes to the fuse panel. Now use a portable 12v charger or jumper cables from a battery to power the furnace by itself and see if that still happens.

If not then at the fuse panel, is there anything else sharing that fuse with the furnace that could be adding amps?

With so many replaced parts, that leaves many opportunities for something to be not put back together right.

[good2eat]

BFL13 wrote:
Is that the control board fuse on the Atwood or the "furnace" fuse at the DC fuse panel?

The furnace fuse on the fuse.block

[RJsfishin]

A bit larger fuse ?? Naw, too simple to try that.

[dougrainer]

If it does not blow until the burner ignites, it is probably the wires going to the Hi Limit switch. The wires are burner/melted to the burner chamber and when it heats up, it causes the wires to melt slightly and blows the fuse. The wires on this model are extremely close to the burner. Doug

[larry_cad]

Possibly a bad gas valve. 12v turns on the gas valve.

[BFL13]

Is that the control board fuse on the Atwood or the "furnace" fuse at the DC fuse panel?