Perfect combustion yields carbon dioxide, water & heat. Incomplete combustion yields carbon monoxide, aldehydes (both deadly) & soot (carbon). Any time you see soot, something needs to be adjusted. Need air, fuel & ignition to have combustion. Propane relatively safe b/c combustion only occurs from 2.5% to 9.5%.

Please read our Fuel, Oils & Propane page for more information.

Component not complicated. There are three circuits involved. Time delay relay (an electrical switch). Turn furnace on, nothing happens for 20 seconds. Takes leftover hot air out of furnace after flame goes off. Limit switch -- heats up, switch opens. Cools down, switch closes. A safety factor, it says let's shut the furnace off rather than burning the coach down. Sail switch (air prover switch) sits in windstream. If fan doesn't turn fast enough, it will shut down furnace. Thus if you have low voltage, you'll also have a slow fan, and it will be the cause of it not lighting.

Thermostat is a metal coil which is temperature activated. Turn up thermostat, power to time delay relay. 20 secs later, sail switch closes, circuit board has second delay built in -- blows out any leaked propane thru exhaust. After 20 secs, high voltage spark 20-80,000 volts -- opens gas valve and creates spark.

Problem: Turn on thermostat -- zip First, do you have power? Check wires going to the furnace (not just the battery). Maybe a fuse problem? And fuses can be in some strange places.

Problem: If you have power to furnace. Fan runs, but continues to blow cold air. Thermo works, time delay works -- both did their jobs. Maybe sail switch, low voltage, pet hair in air wheel, etc all cause insufficient air flow. Furnace is designed to keep blowing cold air. Thermostat says keep running, but board has gone into lockout. Turn it off and back on again. Wait a couple of seconds, and board will recycle and try again.

Takes long time to heat up a coach. Limit switch will shut down gas when furnace gets too hot --- even if coach isn't well heated yet. Biggest problem is the ducting. for each 10K BTU, need one 4" duct.  But RVers can be sloppy, and cover either duct or return air. If air flow blocked, motor will run faster, since it isn't having to do it's work. Can adversely impact air/fuel mixture.

"Furnace doesn't work". If this is all you tell the service tech, it's not good info -- will cost $ to diagnose. Tell the service tech all the circumstances. Low power supply is often the culprit. You may have been dry camped for 3 days, but tech guy has you plugged in to shore power, and when he tries the furnace it works fine. You'll save dollars by telling the service folks ALL the circumstances involved in any appliance failure.

Propane regulator: Furnace thermostats can be adjusted as to cycle (length on). Fine wire is anticipator. Longer the wire, the shorter the cycle. A "normal" set would be for around 3.5 degrees. Likely thermostat needs to be tailored to the needs of the particular RV in which it's installed. A 35 foot motorhome needs to cycle more slowly, as it takes longer to heat up -- than a 10 foot camper. Ideally, furnace should have a chance to cool down between cycles. They are not "continuous duty" furnace motors. Motors are improved, but still probably the weak link in the system.

Leak test -- a great product is kids bubble stuff. Doesn't have the prohibited ammonia.

Please read our Furnace page for more information.

The optional roof-mounted air conditioner can operate only when the motor home is connected to 120-volt AC power from either a public utility or the generator. Be sure to turn the air conditioner circuit breaker ON. 

For best performance, park the motor home in the shade and close curtains. Close doors and windows and turn the temperature control knob for desired coolness. Refer to the air conditioner manufacturer's instructions for detailed operating and preventive maintenance requirements. Remember that air conditioners use a large portion of your available electric power.

Water Heaters

AC, propane, motoraid. Okay to run AC and propane at the same time. Can give you faster recovery time. Motoraid problem is it's not thermostatically controlled. Can produce dangerously hot water. Especially tough on kids, grandchildren.

Two types...alum and steel lined tank. Atwood aluminum tank. Suburban steel lined tank. Anode rod is in steel tank only, to prevent electrolysis. Newer ones are in the drain...easily removed and inspected when you drain the tank. Atwood offers aftermarket anode rod, but they're useless.

Pressure/temperature relief valve. Good idea occasionally to open them and let them snap shut. Air gap should be at the top. If air pocket is gone, let air in. Flush monthly. Don't run the water heater electric element without water in it!

Please read our Water and Plumbing pages for more information.

Inverters: Most buyers want to use microwave ovens. They figure a 1,000 watt inverter will run a 800 watt microwave. Wrong. Usually the "800" watt microwave will draw as much as 1,500 watts. Check inside the microwave door to get the "real" power consumption.

Use a surge protector (computer type) where the microwave plugs into the the wall. Surges will cause the microwave fuse to trip, and the entire unit needs to be taken out of the wall to repair it.

You may have additional appliances in your unit which operate only when connected to 120-volt power from either a public utility or the generator.

In some cases appliance selector switches are provided on the galley to allow you a selection of appliances yet still remain within the power capacity of the electrical system.