Furnace wiring

[worm_54]

I have a new Atwood 16,000 forced are furnace. I have it wire up to the thermostat, but I'm not sure where to go from there. Battery or converter? If it should go to the battery, do I need an inline fuse or anything else before the battery?

Any advice is appreciated...

[papadarv]

If you have a converter installed in your ice house, the furnace along with all other 12VDC devices should be wired to one of the available 12 VDC fuses (usually "blade" type fuses) in the converter distribution panel. The + wire (usually red for 12 volts goes to the back side of a fuse. The ground (usually black) to the ground bar. Read the install wiring part in your Atwood manual for wiring details. When the converter is plugged into 120 ac (i.e. your house or generator via an extension cord) the converter charges the battery and provide 12 VDC to lights, furnace, what ever else 12 VDC you using. When on the Ice, no generator everything runs off the battery. Converters use automatic switching.

[delcecchi]

Be sure to use big enough wire to avoid excess voltage  drop.

[worm_54]

Thanks for the replies, but...I am reading the manual, that's the problem. I have the furnace wiring routed to the converter just like everything else (lights, fans, radio, dc outlets etc), then I read this in the manual. I am using a WFCO-8900 series converter and 14awg wire.

For best performance of furnace when power supply is from a converter equipped
with a charging port, wire the converter to furnace parallel with battery. This provides
consistent voltage to furnace, increasing component life, filtering power
surges and AC spikes FIG 4-G & H.

[Moon Lake Refuge]

Need to know wire length to know if 14 is big enough but I can't think of any reason you wouldn't wire it directly to the converter.  Has a built in fuse for protection and seems to be the standard from what I have seen in factory houses.  Now queue lip ripper to come correct me and give a valid reason why I'm wrong 

[worm_54]

I'm going to say 19-21 ft, through the cabinet, up the wall and over to the converter. I think I'm pretty close with 14, depending on what chart or calculator you look at. Probably should have gone with 12.

[Moon Lake Refuge]

That's about ours  and I went 12.  I always err on caution 

[Lip_Ripper Guy]

12 is what I've always used, but you might be okay with 14.  If it is something that can be re-run, heavier would definitely be better.  

[worm_54]

Thanks all, I'm going to rewire with 12.

But, I'm still not certain which way is correct to wire.. to converter or straight to the battery? The above diagram is from the manual, and explains ' if your convertor has a charging port ' wire it in parallel, converter-battery-furnace. I'm not sure their meaning of 'charging port '.

[Moon Lake Refuge]

Call the manufacturer of the furnace and ask why they recommend that when most rv's wire them to the converter.  

[papadarv]

3 hours ago, worm_54 said:

Thanks all, I'm going to rewire with 12.

But, I'm still not certain which way is correct to wire.. to converter or straight to the battery? The above diagram is from the manual, and explains ' if your convertor has a charging port ' wire it in parallel, converter-battery-furnace. I'm not sure their meaning of 'charging port '.

In your photo, G is the Charging Port, H is the Battery. Not shown is the converter. The battery is - wire connected to the converter DC ground Buss (bar with screws thorough hole for wire) and the + wire to the fuse Buss. In parallel means to the fuse and buss or direct to the battery as both are wired to one connection. Your converter may not have an extra box as a charging port, its most likely built into the converter so you need not worry about the charging port.

If you choose to connect to the battery you MUST put a fuse in-line on the + wire between the battery and the furnace. What ever amp the specs state. If you wire to the fuse buss, than you already have an in-line fuse. Just make sure the fuse size is per the spec. of the furnace.  The 9 blue things in the upper right corner of this photo are the fuses. This converter has the + wire connections just below each fuse. Other converters the connectors will be located behind the panel. The ground bus which is a solid bar is located behind the fuse panel. The two large connectors to the right of the fuses are also ground buss connectors.

Connect your furnace + wire to one of the fuses and the ground - wire to the ground buss. It will than be weird in parallel with your battery. Replace the fuse if the Amperage of the fuse is different from the manufacture specification.

 The circuit breakers in the upper left panel are A/C breakers (just above the word MAIN.) There are 2 breakers in addition to the main breaker. This is where you connect you A/C wires to your outlets. AC Wires are ALWAYS on the back of the panel because you really don't want to touch the wires when live as they have 120 VAC. Black AC wire goes to the fuse and White and bare copper wire to the ground buss, most likely located below the breakers on the back side.

[Lip_Ripper Guy]

Sorry, I missed part 2 of your question.  It looks like a couple people have answered the question in different ways.

I use the Progressive Dynamics PD4045, which is similar to your WFCO-8900.  You run the + wire from your converter (which should have a fuse), to the + wire on your furnace.  Because it is such a high-draw appliance, I'd dedicate a circuit solely to the furnace.  The - wire on your furnace can be connected to the frame if you are doing a DC frame ground, or (2) to a - ground bar (and then the frame or battery), and/or (3) directly to the - on your battery.  All 3 options will accomplish (kind of) the same thing.  I did a ground bar behind my power panel, and connected the individual appliances to that, and then one 12ga wire directly to the battery -.  

There should be two extra wires for the furnace, generally blue.  Those get connected to your line-volt thermostat, and trigger the furnace to turn on and off.  Nothing complicated there.  

[worm_54]

Finished rewiring to furnace with 12. Added some pics of the finished job. I have 2 4-bank switches (one for lights one for fans), 2 DC chargers, radio, CO/LP detector and the furnace.

Oh, and 4 AC outlets.