Heat stops working

[HeatherAilie]

Hello! I recently received a 1995 Dutchmen Classic 360 and really need help. I am a super newbie but eager to learn. Our biggest issue is the heat right now. It starts off perfectly fine but sometime through the night it starts to blow cold. We woke up to 39 degrees in our camper! One thing that worked before (but now isn’t) was to turn the furnace off and back on. That worked once but not again. I’m clueless and freezing! Please help.

 

[persistent]

Hello! I recently received a 1995 Dutchmen Classic 360 and really need help. I am a super newbie but eager to learn. Our biggest issue is the heat right now. It starts off perfectly fine but sometime through the night it starts to blow cold. We woke up to 39 degrees in our camper! One thing that worked before (but now isn’t) was to turn the furnace off and back on. That worked once but not again. I’m clueless and freezing! Please help.

Post make and model number of the furnace for better advice.

A 20 year old furnace can easily have several different failure modes.

Start with recommended annual inspection and cleaning. See Owner's Manual.

Generally speaking, the furnace fan should shut off when temperature inside the furnace drops. Continuing to run may not be normal. It may depend on the furnace design. Post make and model.

The typical cycle is as follows:

The "sail switch" that detects air flow must be "OFF" before the fan will start.

The fan starts. There must be enough air flow to switch the "sail switch" "ON". If it does not, the gas valve will not open and the spark igniter will not try to light. The fan may continue to run slowly and blow cold air.

Clean the dust and insects out of furnace. Clean air passages and especially clean the "sail switch". Often the furnace must be disassembled to do this. See manual for best method.

Another possibility is the control board is not working properly. Replace it.

Loose wire connections inside can cause strange behavior.

 

[HeatherAilie]

Thank you for responding. The make is hydro flame corporation (I believe) and model number is 8535-IIIV

 

[HeatherAilie]

 

[persistent]

I could not find a manual on the internet. It may be older than the internet data. Atwood, Dometic, and Suburban all made "Hydro Flame" models. I could not find a "hydro flame corporation" reference.

You may get more experienced advice on www.irv2.com. A user named Old-Biscuit may do better.

You also could take it to an RV service center. A service technician may be able to see issues better.

 

[Franktafl]

Are you sure you are not out of gas?

 

[Franktafl]

The 8535-IV is a forced-air propane furnace for RVs that uses a heat exchanger to circulate air into a living space. It's similar to a household furnace.

Here are some parts of the 8535-IV:

blower wheel, sail switch, control board, circuit breaker, gas valve, electrode, burner head, motor, combustion wheel, and limit switch.
You can buy parts for the 8535-IV from a number of online retailers, including:

• Amazon: Sells replacement circuit boards, motors, igniters, and more
• Pdxrvwholesale.com: Sells tune-up kits, blower motor and wheel kits, and more
• eBay: Sells new and used furnaces

It looks like hydro flame was purchased.

This is a parts breakdown for the Dometic™ (Hydroflame) 8535-IV RV Propane Heater / Furnace

Dometic™ (Hydroflame) 8535-IV RV Propane Heater / Furnace - 35K Parts Breakdown

This is a parts breakdown for the Dometic™ (Hydroflame) 8535-IV RV Propane Heater / Furnace. The 8535-IV is a forced-air furnace that uses a heat exchanger to force the heater air into your living quarters, similar to a household furnace. The breakdown includes the blower wheel, sail switch...

pantherrvproducts.com

What’s strange, this site says Atwood:

Atwood / HydroFlame Furnace Model 8535-IV Tune-Up Kit

Atwood / HydroFlame Furnace Model 8535-IV Tune-Up Kit

pdxrvwholesale.com

This site sells what they call a “tune up kit” which contains all the parts you should need to get it back working again (except for the thermostat and Propane)!

 

[Franktafl]

Yes, Atwood is owned by Dometic; in 2014, Dometic acquired Atwood Mobile Products, meaning Atwood is now a part of the Dometic company and its products are sold under the Dometic brand.

 

[chrisski]

I want to add the igniter. If this is clicking, but not lighting, it could need adjusting or replacing. I put the two prongs of the igniter about a 1/4” apart and a 1/4” above the screen. I also test it and the spark should go between the prongs, not to the screen.

 

[capeharj]

Hello! I recently received a 1995 Dutchmen Classic 360 and really need help. I am a super newbie but eager to learn. Our biggest issue is the heat right now. It starts off perfectly fine but sometime through the night it starts to blow cold. We woke up to 39 degrees in our camper! One thing that worked before (but now isn’t) was to turn the furnace off and back on. That worked once but not again. I’m clueless and freezing! Please help.

If your bottles are less than half full and the temp drops close to freezing, the propane won't have the required pressure for furnace operation. Your stove and hot water heater will probably work but not the furnace, it has a limit switch on the line pressure.

 

[persistent]

If your bottles are less than half full and the temp drops close to freezing, the propane won't have the required pressure for furnace operation. Your stove and hot water heater will probably work but not the furnace, it has a limit switch on the line pressure.

I run my propane furnace from a pair of "20 lb" tanks. I have frequently used the furnace down to 20 degrees F. I have sometimes run the tanks empty. I have never had a problem with half full or less tanks.

Output pressure from two stage regulator should be around 11 inches of water. Some furnaces say 10 inches.
Defective regulator
Regulator obstructed with oil or water
Propane gas line obstructed with oil or water
Pressure may drop with high gas flow rate. This may mean defective regulator.