How Do I Start My Heater Furnace?

[mobilehippo]

Hi,

I'm trying to trouble shoot my heater furnace of my 1979 Toyota Odyssey. This propane heater furnace is pretty old but maybe someone with an old model might be able to help me.

I've included some pictures.

So I've tried different combinations of things. I am not sure whether I'm doing the procedure wrong or if maybe something is broken. I turn on the propane. I know this works because the stove and hot water heater work fine.The heater has a red knob with Off, Pilot and then On. I put the red knob to Pilot. Then there is a switch to ignite the pilot. I press that down, I hear the click and let go. I can't hear any gas coming through at this point and of course when I go to On it definitely doesn't work. Then I tried this again but this time I held the Ignite switch compressed for about a minute. Still I don't hear anything.

Then I tried this combination, I turn the thermostat to high, till I hear the fan. I read somewhere about a sail switch. Then I turn red knob to Pilot, Then I switch on the ignite. This also doesn't work cause it wont activate. I might be hearing the propane running but with the fan blowing I dunno if the pilot can stay lit. It doesn't make much sense but I never used one of these before.

I have a theory either my switch to ignite might be broken or I'm really just not holding it down long enough. I had to hold the pilot button down on the hot water heater for a good 4-5 minutes to keep it lit.

What is the right procedure?

Thanks!!

[zero]

Since your furnace works with a pilot-light and not electronic ignition -there is no "switch" for igniton. You probably have a piezo push-buttom that makes a mechanical "snap" and hopefull makes a spart by your pilot-light gas jet. They can go bad and new onlys can be had for $10. You can also just light it with a match.

There will be a little trap door by the pilot with a wing-nut on it or a screw. Open it, hold the red pilot button "in" and see if you can light it. If it lights - hold the button down for 30-60 seconds and then let go. If it stays lit - you are good to go. If not, you probably need a new $10 thermocouple tube. If the pilot will not light at all - it's plugged. Most old furnaces I come across have plugged pilot jets. Very easy to take apart and clean.

[Derek up North]

I just stumbled across this:-

http://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf

Might or might not apply to your vintage of furnace.

EDIT:- Another to look at:-

http://bryantrv.com/docs2/docs/hflameservice.pdf

[mobilehippo]

Thanks for all the responses. Unfortunately I haven't been able to find a PDF on instructions for the vintage furnace. It's pretty old. Though the owner did say it worked who I bought it from.

I wish I could see where i would light the pilot. I do indeed have the Piezo switch as indicated. Would anybody be able to help me figure where I could manual light it with a match?

I included some more pictures.

[Derek up North]

Do you know what the model # of the furnace is?

[zero]

Thanks for all the responses. Unfortunately I haven't been able to find a PDF on instructions for the vintage furnace. It's pretty old. Though the owner did say it worked who I bought it from.

I wish I could see where i would light the pilot. I do indeed have the Piezo switch as indicated. Would anybody be able to help me figure where I could manual light it with a match?

I included some more pictures.

That looks like an odd-ball furnace, i.e. I don't recognize it. Most furnaces e.g. Suburban NTs that come with a pilot light also have a small trap door (for manual lighting) or a small glass window so you can see inside where the pilot flame and Piezo spark is supposed to be. Inside the circles I drew. On your's I don't see either but the photo of the pilot area is not very clear.

[Derek up North]

Here's an older manual:-

http://bryantrv.com/docs2/docs/hflameservice.pdf

[mobilehippo]

My guess is this because someone else posted in a yahoo group with the same model rv. It's definitely Hydroflame. I think HF7712 is the model number.

Thanks!

[mobilehippo]

That looks like an odd-ball furnace, i.e. I don't recognize it. Most furnaces e.g. Suburban NTs that come with a pilot light also have a small trap door (for manual lighting) or a small glass window so you can see inside where the pilot flame and Piezo spark is supposed to be. Inside the circles I drew. On your's I don't see either but the photo of the pilot area is not very clear.

Yeah I don't see any trap door or glass window......

Do you know if I have to hold down the piezo switch or should that one spark light the pilot?

Thanks again for all the help!

[Derek up North]

This manual is supposed to cover the 7700 Series.

http://bryantrv.com/docs2/docs/FA7200.pdf

[zero]

Yeah I don't see any trap door or glass window......

Do you know if I have to hold down the piezo switch or should that one spark light the pilot?

Thanks again for all the help!

No you don't hold it down You must let go, let it re-set itself and push again. Over an over, one brief spark for each "snap" if it's working. Same idea as an impulse coupling on an old farm tractor magneto. It relies on a fast moving little hammer that strikes a piece of quartz. If it does not "snap" it cannot work. Piezos also don't work well in extreme high altitudes.

[Gulfstream Greg]

Hold down the light pilot knob for a long period of time ( DON'T PRESS THE PIEZO LIGHT BUTTON) then go out to the exhaust vent, stick your noise down there and give it a sniff. You should be able to smell gas at that point. No gas smell - gas problem, gas smell - piezo problem. Also the chance both are a problem. The sail switch is a safety device. It activates when the circulation fan is running and tells the gas valve that it can release gas to the main burner. When you make a call for heat the fan first turns on activating the sail swith then a few seconds later the gas valve opens to the main burner and the pilot lights it up. In reverse when the call for heat ends the the gas to the main burner turns off but the fan continues to run to cool down the combustion chamber. You should also have a thermocoupler for the pilot. If the thermocoupler is bad the pilot will not stay lit. The thermocoupler also signals the valve that the pilot is lit and that the valve can supply gas to the main burner when heat is called for. The electronic start heaters all work the same except that the electronics generate the piezo spark and the piezo spark wire also acts as the thermocoupler telling the gas valve that there is pilot flame. The electronic furnaces light the pilot everytime there is a call for heat. Then the pilot extinguishes at the end of the call for heat. The non electronic pilots stay lit until you tun them off via the valve knob.

Also have you followed the gas line to make sure there is not a on/off valve somewhere for that line.

I also recommend getting a carbon monoxide (CO) detector for your RV's. Heaters can easily transfer CO into the RV if there are cracks in the heating chambers. Without a CO detector you'll just be dead if there is a CO problem.

[grandview bill]

15 years ago my next door neighbor and his brother in law went up in No.Minnesota deer hunting in their small camper, they never woke up again, they were both killed in their sleep by a faulty furnace. A heating appliance in an very small area can be lethal, many rvs sit for long periods with little use, rusting of the heat exchanger can be an issue. Over the years Ive heard many a camper who told me they will never use a furnace. I wont sleep one night in an rv without a working CO and smoke detector. mine are mounted on a separate board an a hook at nite. I prefer the CO detector that gives a numerical reading even at low values before the alarm sounds. With this latest rv I test the furnace by setting the temperature to turn on the heat .....over a 12 hour period I check the status of the CO digital readout, it was zero. Years ago we would check a heat exchanger with a lamp put inside when it was dark out looking for pinholes and cracks