2006 National Dolphin no hvac

[TFarmer]

Hey guys I just bought a 2006 Dolphin. I can't seen to find out why the Heat and air controls won't come on. No lights or nothing. The owner said he thought it had ran out of LP and didn't worry about it. But it has 1/2 tank. Its like im missing a switch or something? Also I don't think the converter is working. All breakers are good. Thought I would ask before taking this thing apart chasing wiring. I have a kill switch by the door and it works like it should. If the converter is bad would it make the heat and air not work or do I have two problems?
Thanks Timmy.

[MrMark52]

Assuming your talking about the rooftop mounted HVAC unit - you probably have 2 problems.
Rooftop cooling or heat pump units need 120VAC to operate - 12VDC is not needed..

If your talking about the LP fueled furnace - they do need 12 volts to operate - no 120VAC is needed.

If your talking about the dash air and heat - that is all 12 volt and is a mixture of chassis and coach builder supplied parts. You will need to confirm and get documentation for both your chassis and coach to figure out who provided what.

For a coach the age of yours - you need to replace the convertor anyway. Those old linear convertor’s will cook your batteries. Progressive Dynamics (and a few others) makes drop in replacement 4 stage convertor’s.

[TFarmer]

Originally Posted by MrMark52

Assuming your talking about the rooftop mounted HVAC unit - you probably have 2 problems.
Rooftop cooling or heat pump units need 120VAC to operate - 12VDC is not needed..

If your talking about the LP fueled furnace - they do need 12 volts to operate - no 120VAC is needed.

If your talking about the dash air and heat - that is all 12 volt and is a mixture of chassis and coach builder supplied parts. You will need to confirm and get documentation for both your chassis and coach to figure out who provided what.

For a coach the age of yours - you need to replace the convertor anyway. Those old linear convertor’s will cook your batteries. Progressive Dynamics (and a few others) makes drop in replacement 4 stage convertor’s.

It is under the right rear of the truck. LP or ELE. so the thermostat says. It probaly is the converter. It is a Xantrex 458. Im new to this part of the r/v but Is that a good unit or what would you replace it with? Thanks for your help.

[TFarmer]

Originally Posted by TFarmer

It is under the right rear of the truck. LP or ELE. so the thermostat says. It probaly is the converter. It is a Xantrex 458. Im new to this part of the r/v but Is that a good unit or what would you replace it with? Thanks for your help.

I have my older r/v that Im gonna sell. It has a good Xantrex 458 on it that I could try. Before spending the money. But it doesn't have the two breaker switches on the front of it. Would that matter?

[MrMark52]

Mmmmm - do you have the owner manual for the coach? If so, you need to read through it familiarize yourself with how things work. If not, do some search ing and see if you can download one from somewhere.
You also need both coach and chassis wiring diagrams.

For some reason what you describe for a thermostat isn’t clicking with me right now. Furnace heaters for MoHo’s are usually LP fired with controls and blower being powered by 12VDC (coach batteries), so not sure what “LP and Elec” on the thermostat is describing.

The Xantrex 458 is an inverter/convertor and is designed to treat batteries right.

You should download all operation and service manuals for your furnace, Xantrex, oven, A/C unit, water heater etc. and study them. They will go a long way toward your understanding how your coach works - and better prepare you to ask informed questions when coming to IRV2.

You’ll also need a voltmeter - Harbor Freight has some decent ones - I suggest the ~$99 one as it has a clamp on DC ammeter built into it.
Don’t worry if you don’t know how to use it - we can teach you.

[TFarmer]

This is the wall thermostat.

[TFarmer]

Originally Posted by TFarmer

This is the wall thermostat. Attachment 381231

Here is the unit. It does not have roof units.

[TFarmer]

The unit is on this rear corner under the truck.

[MrMark52]

Ohhhhh - you have what’s called a dual fuel heating system. As long as you have LP, you can use the furnace. And if your out of LP, and if you have either shore power or the generator is running, you can use electricity to heat the coach.

If you have plenty of LP and shore power or generator, you can use whichever one costs less to operate provided that when using electric that it can keep the coach warm (LP furnaces can usually keep the coach warm without issue).

Nice coach!

[fredbon]

Timmy, I haven't heard you mention your power supply. Your invertor will not power the basement air/heat. So, are you running the generator?

Fred

[TFarmer]

Originally Posted by fredbon

Timmy, I haven't heard you mention your power supply. Your invertor will not power the basement air/heat. So, are you running the generator?

Fred

I have tried both, Generator and plugging it in. Seems like Im missing a switch or something. I don't see a master battery disconnect switch. Just the one when you walk in to the left. My other r/vs have had disconnect switches. Did National not use them?

[TFarmer]

Originally Posted by MrMark52

Ohhhhh - you have what’s called a dual fuel heating system. As long as you have LP, you can use the furnace. And if your out of LP, and if you have either shore power or the generator is running, you can use electricity to heat the coach.

If you have plenty of LP and shore power or generator, you can use whichever one costs less to operate provided that when using electric that it can keep the coach warm (LP furnaces can usually keep the coach warm without issue).

Nice coach!

Thanks I like it. Just hope its not trouble.

[TFarmer]

Are these dual fueled units connected to the inverter in any way? I think I have a problem with it also. I may have two problems.

[Pelledan]

I have the same system in my 2006 Journey. Doo you have an "AUX Batt" switch on the dash? If so, that must be in the "ON" position as it is the connection for your house batteries. Everything 12 volts inside the coach needs that switch on to operate. The A/C, Heat, Refrig, Propane Detector all have 12 volt control systems powered by those batteries. If that switch is on and some things work and others don't, look for you 12 volt circuit breaker panel as you may have a blown fuse. My panel is in a compartment right below the refrig and there is another in the front of the coach accessed through a "hood" on the outside front of the vehicle.

Dan