Community Forums

djones · 03-21-2010, 09:24 AM

Hello all,
Don here with a question or two. I received some answers from Dean and I wrote another note to him but lost it in the maze.
We are close to purchasing a new to us '97 Magna. It has some issues and some other input might help us out.
There is one thermostat above the entry door. It has 2 zones and I think it is used for heating and cooling. There is one thermostat only in the coach. Does this run the two furnaces and the two roof air units? I can't get it to start the rear furnace. I have propane to both furnaces and the front blows cold air only. I assume the circuit board needs replacing to the new model.
The rear furnace will not start or blow air. Possible fuse etc.
There is a cooling(?) unit above the head of the bed. Is this a rear air cond off the main engine? There is only one control for heat and dash air located on the dash.
The coach has two 8D battieries for the house. Are these in series or is there two seperate 12V systems to the coach?
There are two 8D batts. for the engine...are these in series or is it a 24v start system?
Thanks in advance for any help, Don in Montana

RV Wizard · 03-23-2010, 02:56 AM

Don, the one T'stat controls all of your heating and air conditioning but for the engine dash. I would ask, how many buttons are on the T'stat. If four only, this is no longer available and if it fails you must upgrade the roof air conditioner control boards to work with the newer 5 button T'stat.
To change zones with the four button you have to hold down the top two buttons; watch for the 2 to blink. If the rear furnace does not run; check for power.
Keep trying the front furnace, as you may have air in the lp fuel line. I would recommend you have the furnaces serviced before using them and keep the bugs out of the outside vents.
The cooling unit above the bed is probably the roof rear air conditioner.
The coach house and chassis electrical systems are 12 volt. The 8 D batteries should be installed in parallel for the chassis. The house could be using one for the inverter and one for the house and thus not wire together.
Good luck and keep us posted.

deandec · 03-26-2010, 03:42 PM

Don, the below info is based on my rig. Except for the battery info, yours may differ.

Quote:

Originally Posted by djones

Hello all,
Don here with a question or two. I received some answers from Dean and I wrote another note to him but lost it in the maze.
We are close to purchasing a new to us '97 Magna. It has some issues and some other input might help us out.

There is one thermostat above the entry door. It has 2 zones and I think it is used for heating and cooling. There is one thermostat only in the coach.
This sounds like a diesel fired furnace set up since one thermostat and two zones. Webasto or Aqua Hot type heating.

Does this run the two furnaces and the two roof air units?

I can't get it to start the rear furnace. I have propane to both furnaces and the front blows cold air only.
If you have propane to a front furnace, then your sail switch may not be getting enough air to trigger, or possibly your igniter is not working. Be sure your house batteries have a good 12.6v charge in them.

If the rear propane furnace does not react, then a fuse may be the problem. If it is a diesel fired furnace, then the zone must be selected first.

I assume the circuit board needs replacing to the new model.
Replacing the control boards might solve the problem.

The rear furnace will not start or blow air. Possible fuse etc.

There is a cooling(?) unit above the head of the bed. Is this a rear air cond off the main engine?
Above the foot of the bed is the Rooftop AC/Heat pump.

In the cabinetry at the head of the bed is the OTR AC rear fan blower.
Temp and AC on/off is controlled at the dash.
Fan speed and on/off of rear blower is at the passenger night stand.

There is only one control for heat and dash air located on the dash.
Yes, see above.

The coach has two 8D battieries for the house. Are these in series or is there two seperate 12V systems to the coach?

The coach is a 12v system exclusively wired in parallel.
Two 8D 12v house deep storage batteries with about 210 AMP hours each or 420 AH total.

There are two 8D batts. for the engine...are these in series or is it a 24v start system?

The batteries are connected in parallel and it is a 12v system.
Two 12v starting batteries @ 1300CCA 8D each.

Thanks in advance for any help,T
Don in Montana