I have offered to consult with a young couple in our neighborhood that just purchased a late 80's Class C motorhome but have no previous experience with RVs. All my experience is with TTs starting with our first new one purchased in '99.After meeting the couple, doing initial RV checkout and going over some of the basics with them, I have a few questions.The range and oven function but I was puzzled that the oven control had a pilot position but you did not have to push the temp/pilot knob to light the pilot while waiting for the thermocouple to heat up. The pilot lit and the burner operated when rotated past the pilot setting. The house battery is in the Ford van engine compartment on the driver's side but only measured 7 volts (engine off) while the engine battery on the passenger side measured 12.5V. The house battery was getting charged once the engine was started but it is going to need replacement due to age and state of discharge. How is the house battery typically isolated from the engine battery when the engine is off? The coach battery monitor read "all lights on" but the LP detector correctly had a low voltage light on. Both should have read low battery with engine off. Is it possible that the coach battery monitor was measuring the engine battery rather than the house battery?Thanks,

New Fords have a relay that is opened/closed with the ignition circuit power (key in run position), don't know how far back that goes. That would isolate the coach battery. Idiot light battery monitors are notoriously bad. Installation of a simple voltage gauge is cheap and fairly accurate.

That range setup is not unusual, or at least was not unusual relatively recently. There are two valves to control the oven, the thermostatic valve (which the knob attaches to) and a safety valve (hidden in the back somewhere). The pilot flame is on whenever the thermostatic valve is not off, but it varies in size: if no heat is being called for, it's a tiny little flame, but when the thermostatic valve detects it needs to turn the oven on, it increases the gas flow to the pilot and turns on gas to the safety valve simultaneously. There is a bulb by the pilot that controls the safety valve; when the bigger pilot flame warms it enough, the safety valve opens and the main burner gets gas and lights. Once the proper temperature is reached, the thermostatic valve closes the gas to the safety valve and cuts the pilot back down to a little flame, and the safety valve soon closes when the bulb cools off.It is possible for the pilot to go out and still have some gas flowing to the pilot burner with this setup.

DrewE wrote:That range setup is not unusual, or at least was not unusual relatively recently. There are two valves to control the oven, the thermostatic valve (which the knob attaches to) and a safety valve (hidden in the back somewhere). The pilot flame is on whenever the thermostatic valve is not off, but it varies in size: if no heat is being called for, it's a tiny little flame, but when the thermostatic valve detects it needs to turn the oven on, it increases the gas flow to the pilot and turns on gas to the safety valve simultaneously. There is a bulb by the pilot that controls the safety valve; when the bigger pilot flame warms it enough, the safety valve opens and the main burner gets gas and lights. Once the proper temperature is reached, the thermostatic valve closes the gas to the safety valve and cuts the pilot back down to a little flame, and the safety valve soon closes when the bulb cools off.It is possible for the pilot to go out and still have some gas flowing to the pilot burner with this setup.So this arrangement is apparently not considered to be a safety issue?

westend wrote:New Fords have a relay that is opened/closed with the ignition circuit power (key in run position), don't know how far back that goes. That would isolate the coach battery. Idiot light battery monitors are notoriously bad. Installation of a simple voltage gauge is cheap and fairly accurate.There appeared to be two old type Ford starter relays tucked behind the driver side of the radiator at the top. These appeared to be wired into the large cable(s) eventually going to the house battery positive terminal.

One solenoid connecting both batts together is activated by a momentary switch on the dash for emergency starting in the case that either battery is dead.The other solenoid is activated by the ign on circuit to connect both batts together anytime the engine is running for charging.The led lites mite be cheap, but they work. Sounds like it may be reading the chassis battery. Some models you have a choice to monitor either battery

Late 80's RV Questions | Good Sam Community

12 Replies

dclark1946
Explorer
Apr 10, 2017
MEXICOWANDERER wrote:
If the rig is destined to be a power pole princess, then 99.99% of the advice given for serious engine alternator charging (upgrades) can be ignored. Late 80's converters were battery boilers. If the converter is a bright brushed aluminum box about the size of a loaf of bread with large red & white wires sticking out of one end and has a fan on the other, let me know -PM- if the owner wishes to upgrade.

Easier than watching pretty, colored, monitor lights on a power pole princess, switch on a light, if no light, problem. Both are useless for battery monitoring.

The young couple plan on using this motorhome for both on and off grid scenarios and will probably live in it most of the time. They have also expressed an interest in solar power after I mentioned our small (110 W) system. I will check on the converter next time I am over there. The power panel has a brown plastic cover similar to our TT's WFCO converter but not sure if it has been changed out.

The RV has not been powered up or connected to city water since their recent purchase. The new owner will be purchasing a new 30A extension cord,new house battery, DMM, RV hoses and pressure regulator so we can complete initial checkout.

Thanks for all the helpful information.
MEXICOWANDERER
Explorer
Apr 06, 2017
If the rig is destined to be a power pole princess, then 99.99% of the advice given for serious engine alternator charging (upgrades) can be ignored. Late 80's converters were battery boilers. If the converter is a bright brushed aluminum box about the size of a loaf of bread with large red & white wires sticking out of one end and has a fan on the other, let me know -PM- if the owner wishes to upgrade.

Easier than watching pretty, colored, monitor lights on a power pole princess, switch on a light, if no light, problem. Both are useless for battery monitoring.
dougrainer
Nomad
Apr 06, 2017
Dusty R wrote:
There is a difference in those relays.
A starter relay is not rated for continuos duty, the relays being used/talked about here are continuos duty.
Just info in case one of you need to change one.

Dusty

Bingo, They ALL look alike, but their GUTS are different depending on the load required. Rarely will you find a continuous duty at a Auto parts store. Doug
Dusty_R
Explorer
Apr 06, 2017
There is a difference in those relays.
A starter relay is not rated for continuos duty, the relays being used/talked about here are continuos duty.
Just info in case one of you need to change one.

Dusty
dclark1946
Explorer
Apr 05, 2017
Thanks for the great feedback. It has helped me understand tech issues that I am not familiar with. I will be getting back with the couple soon since we have a lot more checkout to do before their RV is ready for a shake down short camping trip. We still need to connect city water and check for leaks and functionality, check holding and fresh water tanks, waterpump and apply ac power. This will be interesting and a learning experience.
westend
Explorer
Apr 04, 2017
dclark1946 wrote:
westend wrote:
New Fords have a relay that is opened/closed with the ignition circuit power (key in run position), don't know how far back that goes. That would isolate the coach battery.

Idiot light battery monitors are notoriously bad. Installation of a simple voltage gauge is cheap and fairly accurate.

There appeared to be two old type Ford starter relays tucked behind the driver side of the radiator at the top. These appeared to be wired into the large cable(s) eventually going to the house battery positive terminal.
Yes, using a solenoid for switching charge voltage to the house battery is a typical arrangement. The solenoid is powered by the ignition circuit. The coach may also have an "Emergency" battery power joining feature that connects the house battery to the engine starting battery, should that battery become low. The second solenoid may be used for that function.
dougrainer
Nomad
Apr 04, 2017
dclark1946 wrote:
DrewE wrote:
That range setup is not unusual, or at least was not unusual relatively recently. There are two valves to control the oven, the thermostatic valve (which the knob attaches to) and a safety valve (hidden in the back somewhere). The pilot flame is on whenever the thermostatic valve is not off, but it varies in size: if no heat is being called for, it's a tiny little flame, but when the thermostatic valve detects it needs to turn the oven on, it increases the gas flow to the pilot and turns on gas to the safety valve simultaneously. There is a bulb by the pilot that controls the safety valve; when the bigger pilot flame warms it enough, the safety valve opens and the main burner gets gas and lights. Once the proper temperature is reached, the thermostatic valve closes the gas to the safety valve and cuts the pilot back down to a little flame, and the safety valve soon closes when the bulb cools off.

It is possible for the pilot to go out and still have some gas flowing to the pilot burner with this setup.

So this arrangement is apparently not considered to be a safety issue?

Yes and No. Maybe you are too young to remember or you never had a Residential Gas Range/stove. Years ago the pilot was always flowing once you went to the pilot mode. Due to safety concerns they now have a push to light pilot assbly or Auto Ignition to prevent gas leaks if the pilot goes out. This used to be a common complaint years ago in RV's. People coming in complaining of LP leaks and we would find the Oven AND The range pilot ON but not lit. Hence a small leak. Some of those ranges also had a positive LP valve shut off under the range top cover to shut off LP to the Complete Range/Stove. Doug
RJsfishin
Explorer
Apr 04, 2017
One solenoid connecting both batts together is activated by a momentary switch on the dash for emergency starting in the case that either battery is dead.
The other solenoid is activated by the ign on circuit to connect both batts together anytime the engine is running for charging.

The led lites mite be cheap, but they work. Sounds like it may be reading the chassis battery. Some models you have a choice to monitor either battery
dclark1946
Explorer
Apr 04, 2017
westend wrote:
New Fords have a relay that is opened/closed with the ignition circuit power (key in run position), don't know how far back that goes. That would isolate the coach battery.

Idiot light battery monitors are notoriously bad. Installation of a simple voltage gauge is cheap and fairly accurate.

There appeared to be two old type Ford starter relays tucked behind the driver side of the radiator at the top. These appeared to be wired into the large cable(s) eventually going to the house battery positive terminal.
dclark1946
Explorer
Apr 04, 2017
DrewE wrote:
That range setup is not unusual, or at least was not unusual relatively recently. There are two valves to control the oven, the thermostatic valve (which the knob attaches to) and a safety valve (hidden in the back somewhere). The pilot flame is on whenever the thermostatic valve is not off, but it varies in size: if no heat is being called for, it's a tiny little flame, but when the thermostatic valve detects it needs to turn the oven on, it increases the gas flow to the pilot and turns on gas to the safety valve simultaneously. There is a bulb by the pilot that controls the safety valve; when the bigger pilot flame warms it enough, the safety valve opens and the main burner gets gas and lights. Once the proper temperature is reached, the thermostatic valve closes the gas to the safety valve and cuts the pilot back down to a little flame, and the safety valve soon closes when the bulb cools off.

It is possible for the pilot to go out and still have some gas flowing to the pilot burner with this setup.

So this arrangement is apparently not considered to be a safety issue?