<%@LANGUAGE="JAVASCRIPT" CODEPAGE="65001"%> RV Propane Appliances
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TOPIC: Propane Appliances


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%.

Oven Ranges: All similar in how they work. Stove top is simplest. Turn burner on, orifice opens, it mixes w/air, nice blue flame. But if you clean w/SOS pad, all the small holes start to plug. The cure is to open the holes with a toothpick or wire brush. Soak first in hot water & soap. Perfectly safe to disconnect using the one screw, clean, and replace.

Okay to access the furnace motor and clean the internal parts. Good preventive maintenance.

Oven has thermostat. Contral valve shuts off heat when it expands. Mercury switch is in the flame which is 2500-3500 degrees. First light pilot. Higher pilot heats mercury valve which opens propane tube & allows oven to go on. Where it is located is crucial. When cleaning, don't want to disrupt location of mercury valve. It will cause oven to overcook everything. Common problem is putting full size cookie sheet which covers air vents, big roasting areas, etc. There are holes in oven which permit air circulation, and if they're covered the bottom of what you're cooking burns, top won't cook.

How to adjust to a lower "simmer" setting: Basically, you can't do it! Many units will simply have a "high", "less high", and "off" capability. The components are not of comparable quality to residential units. Blue flame not really achievable, so expect some yellow/orange tips to the flame. This should improve when the pot is over the flame, as the airflow changes to improve the situation. If you do get some soot, newer units don't have air adjustment. May need to replace burner.

Forced Air Furnace: 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. Too often ducting is inadequate, and contains a too many restrictions (90 degree turns, etc). Manufacturers unfortunately don't engineer this well. 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". I f thisis all you tell the sevice 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: Put a dirt trap (also known as dirt pocket) on your regulator. All home systems have them. It's a 1-2 dollar item, and can save a lot of problems. Not a safety issue. Gives service tech easy access to do pressure check (don't have to disconnect appliances), and can periodically drain residue. .

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

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.