Tried to plug my furnace into my solar.

[JeremyG]

I'm trying to get my gas furnace to work via my 12v solar setup.

I saw a guy on YouTube (and the eyes start rolling), he modified his furnace.
He cut his power input cord from the breaker box (turned the breaker OFF, first, of course) and connected it with a pig tail 3 prong cord.
He plugged that into a gas generator and got his furnace powered via generator.
Similar setups have been done with solar.

I have 12v system.
I was able to modify my furnace the same way. It plugs into a grid outlet (12v) and works normally.

Then, I unplug it from the grid outlet and I to my solar system.
It turns on (the little lcd thermostat in the living room).
It'll turn the fan on...but the gas doesn't trigger and thus, it's only spinning the fan and cool air.

I plug it back into grid and it works normally.

Why does my furnace work normally plugged into 12v grid..but doesn't work normally when plugged into 12v solar?

(I've got about a dozen deep cycle batteries in parallel and 5x 230 watt panels, also in parallel).
I've got an EAsun 80v mttp controller. A 2000 watt pure sine inverter.
In optimal sunny conditions, I've been able to power my kitchen refrigerator for about 12-14 hours.
I can do my washing machine, and most other stuff (tv+ stereo+consoles etc).

So...why won't the furnace work?

Thank you for your help.

 

[LakeHouse]

I'm trying to get my gas furnace to work via my 12v solar setup.

I saw a guy on YouTube (and the eyes start rolling), he modified his furnace.
He cut his power input cord from the breaker box and connected it with a pig tail 3 prong cord.
He plugged that into a gas generator and got his furnace powered via generator.
Similar setups have been done with solar.

I have 12v system.
I was able to modify my furnace the same way. It plugs into a grid outlet (12v) and works normally.

Then, I unplug it from the grid outlet and I to my solar system.
It turns on (the little lcd thermostat in the living room).
It'll turn the fan on...but the gas doesn't trigger and thus, it's only spinning the fan and cool air.

I plug it back into grid and it works normally.

Why does my furnace work normally plugged into 12v grid..but doesn't work normally when plugged into 12v solar?

(I've got about a dozen deep cycle batteries in parallel and 5x 230 watt panels, also in parallel).
I've got an EAsun 80v mttp controller. A 2000 watt pure sine inverter.
In optimal sunny conditions, I've been able to power my kitchen refrigerator for about 12-14 hours.
I can do my washing machine, and most other stuff (tv+ stereo+consoles etc).

So...why won't the furnace work?

Thank you for your help.

The most likely culprits are a N-G bonding issue or a grounding issue.
Furnaces run a bunch of checks before they’ll ignite the fire and if any of them fail, they won’t do it. Your furnace is likely giving you an error code if it isn’t starting. Check out what it’s telling you.
As for the N-G and ground…. Do you have a ground when the system is plugged into the inverter, and is there exactly one N-G bond in that system?

 

[v_green57]

Search the forum for "furnace". You will get a whole bunch of results and some interesting "won't run" problems are discussed.

 

[hafbakd]

NO WAY 12v will make the gas valve work for starters (regardless of when the t'stat calls for heat and that isnt likely 12v either)

 

[Brucey]

NO WAY 12v will make the gas valve work for starters (regardless of when the t'stat calls for heat and that isnt likely 12v either)

It isn't totally clear but he's talking about 12V into "A 2000 watt pure sine inverter."

 

[hafbakd]

and even IF the GV opened and somehow let the ignitor 'think about' firing it, there likely isnt enuf juice 4 that 2 happen and IF THAT FIRING ATTEMPT wasnt already nixed by other safeguards built into the hardware. i hope you are well insured and ready to come to an explosive conclusion taking along some of your neighbors and all 2 save a few $$ if it ever worked // wut were u thinkin dude???

 

[hafbakd]

ok but what kinda juice is that providing

 

[42OhmsPA]

The most likely culprits are a N-G bonding issue or a grounding issue.
Furnaces run a bunch of checks before they’ll ignite the fire and if any of them fail, they won’t do it. Your furnace is likely giving you an error code if it isn’t starting. Check out what it’s telling you.
As for the N-G and ground…. Do you have a ground when the system is plugged into the inverter, and is there exactly one N-G bond in that system?

This

@JeremyG please edit your post to clarify 12V vs 120V.

For clarity... you added a receptacle to the grid feed that runs to your furnace and you added a plug on the furnace end. This allows you to plug the furnace into the grid or into an inverter / generator. You are attempting to run the furnace with your 12VDC inverter.
Correct?

How much power is your igniting pulling?
How is your 12VDC inverter grounded and bonded?

I'm still betting that @LakeHouse is correct and agree with him.

 

[hafbakd]

bottom line is U will need a STABLE + sufficient pwr supply (from wherever) to keep the gas valve ready for action, otherwise it shuts down

 

[JeremyG]

LakeHouse
I don't know what it means to ground the inverter.
Of the dozens of tiny homes and van life + google search research I've done;
Panels are plugged into the mppt controller.
Batteries are plugged into the controller.
Batteries are plugged in parallel (red to red to red. Black to black to black).
They are plugged into the inverter (via black and red plugs in the back).

I've got a power bar plugged into the inverter with a bunch of extension cords coming out of it.
1 for an outlet in the kitchen (for small appliances)
1 for the washing machine
1 for the fridge
1 for the living room (tv, laptop, stereo).

Not all at once. We kinda rotate through the week.

As far as grounding the inverter...no.
There's nothing plugged into the ground pin at the back.

hafbakd
As far as a surprise explosion is concerned.
I tested it out with a gas generator (champion 4450), plugged in with a 100 foot 3 prong extension cord, from the shed to the basement. It worked.
I only ran it for 10 minutes, because the generator is loud, even in the shed).


42OhmsPA
please edit your post to clarify 12V vs 120V.

(I thought 12v was a short form for 120v, like 24v is a short form for 240).


To group a response to the rest of the comments;
I hoped the furnace would fire up with a jolt of power, but once the gas was burned, I hoped the endurance part of the solar system was going to power the fan and keep the house warm.

I can accept if the furnace is defecting an inadequate power source.
My question is, why would the gas generator do it with a 3 prong extension cord, but my solar set up, with a 3 prong extension cord won't fire it up?

 

[42OhmsPA]

LakeHouse
I don't know what it means to ground the inverter.
Of the dozens of tiny homes and van life + google search research I've done;
Panels are plugged into the mppt controller.
Batteries are plugged into the controller.
Batteries are plugged in parallel (red to red to red. Black to black to black).
They are plugged into the inverter (via black and red plugs in the back).

I've got a power bar plugged into the inverter with a bunch of extension cords coming out of it.
1 for an outlet in the kitchen (for small appliances)
1 for the washing machine
1 for the fridge
1 for the living room (tv, laptop, stereo).

Not all at once. We kinda rotate through the week.

Do you have any photos?

As far as grounding the inverter...no.
There's nothing plugged into the ground pin at the back.

We bet that's your problem.

hafbakd
As far as a surprise explosion is concerned.
I tested it out with a gas generator (champion 4450), plugged in with a 100 foot 3 prong extension cord, from the shed to the basement. It worked.
I only ran it for 10 minutes, because the generator is loud, even in the shed).

Does your generator have a neutral ground bond?

42OhmsPA
please edit your post to clarify 12V vs 120V.

(I thought 12v was a short form for 120v, like 24v is a short form for 240).

Please erase that from your memory bank completely. My brain hurts.

To group a response to the rest of the comments;
I hoped the furnace would fire up with a jolt of power, but once the gas was burned, I hoped the endurance part of the solar system was going to power the fan and keep the house warm.

I can accept if the furnace is defecting an inadequate power source.
My question is, why would the gas generator do it with a 3 prong extension cord, but my solar set up, with a 3 prong extension cord won't fire it up?

We need more info about your setup. Photos would really help.
Likely a ground issue.

 

[wheisenburg]

I can accept if the furnace is defecting an inadequate power source.
My question is, why would the gas generator do it with a 3 prong extension cord, but my solar set up, with a 3 prong extension cord won't fire it up?

More than likely the furnace is checking that there is continuity between the neutral and ground wire. If you have a portable generator, it should have a bonded neutral, meaning it has a connection between the ground and neutral wire in the generator. Whole home standby generators will generally not have a bonded neutral and will be tied into the homes electrical system with a separated ground and neutral wire. This is because one is designed to allow stand alone operation, while the other is intended to become a part of your homes electrical system.

If you have a meter with ohms you can test for this. With the generator off check the ground terminal against the neutral. The neutral is the larger of the two parallel plugs. You should get zero or a very low ohms reading. Then with the inverter off, do the same with the power coming from the inverter. If you get an open circuit reading you need a ground to neutral connection on the inverter.

Does your inverter have an AC in connection? If your inverter can charge batteries using AC current it will have a way to connect it to your homes AC system. It might be as simple as plugging your inverter into an AC outlet. If you don't want power going to the inverter use something like a switchable power strip, and turn the power strip switch off. This should still provide the inverter with a proper ground and neutral connection. Without going into all the reasons, the electrical code requires that the ground and neutral systems have a single point of connection at the point where the electricity first enters the house. So by connecting a 3 prong plug to your inverter, you are tying the inverter back to that connection through your homes wiring system. The ground and neutral outlets in the inverter will then look just like the ones in the grid outlet box.

At this point the furnace should be able to see that it has proper electricity connected. You do also need to make sure that the inverter can supply enough power. The fan doesn't take a lot of power, but most modern furnaces use electrical igniters. They essentially heat a piece of metal up to red hot and then shoot gas at it which should ignite the gas. You should get some kind of inverter fault if this is the issue.

If there is no AC input on the inverter, then I think you need to ask one of your electrician friends how to proceed. I'm not going to provide advice on how to Frankenstein it.

 

[JWLV]

(I thought 12v was a short form for 120v, like 24v is a short form for 240).

No! No! No! No! No!
Please, don't ever think that again. 12v is NOT short form for 120v. And 24v is NOT short form for 240v.

12v generally means 12 volt DC such as commonly used in car batteries, although there are some devices that use 12v AC. It's rare to see anything that uses 12v AC. Some door bells are powered by 12v-24v AC (not DC). 120v is generally 120 volt AC, such as your home's wall outlet. AC and DC are two different things. 12v and 120v are two different things. You cannot mix and match and hope for it to work.

 

[wheisenburg]

I'm trying to get my gas furnace to work via my 12v solar setup.

A 12V system here is (hopefully) referring to the battery voltage. Small inverters like this can use 12 volt DC batteries like from a car, but they will output 120 volts AC. Larger inverters often output 120/240 volt split phase from 48 volt batteries. These would be called 48 volt systems if you are talking about the DC voltage.

 

[NC_hydro]

Guys…cmon the OP is trolling all of you lol.

 

[Supervstech]

A gas furnace requires a grounded circuit to detect flame. And the logic board is specifically designed to detect it.

The furnace will not fire without correct polarity, correct grounded equipment.

 

[JeremyG]

NC_hydro
(No, I'm not trolling you).

I saw a guy on YouTube run his furnace with his gas powered generator.
youtu.be/cSXVeUg7L0k

I wanted to know if I could get my furnace to run on my simple 12v solar set up.
I can get the fan to power up, but the gas (and spark) won't trigger.
I haven't had time to read everyone's responses in the last few days.

For me, it's not a question of, 'it can't be done", it's a question of, HOW can it be done.

 

[Supervstech]

NC_hydro
(No, I'm not trolling you).

I saw a guy on YouTube run his furnace with his gas powered generator.
youtu.be/cSXVeUg7L0k

I wanted to know if I could get my furnace to run on my simple 12v solar set up.
I can get the fan to power up, but the gas (and spark) won't trigger.
I haven't had time to read everyone's responses in the last few days.

For me, it's not a question of, 'it can't be done", it's a question of, HOW can it be done.

With a grounded inverter, connected to a bonded neutral, it will work just fine.

 

[JeremyG]

I'll have to post a picture...I think I grounded the 2000watt pure sine inverter.

42OhmsPA mentioned the bonding neutral thing in #11 up there...but didn't explain what it means.
My research hasn't been helpful.

Can you please explain what 'bonding a neutral" means?

Thank you

 

[LakeHouse]

I'll have to post a picture...I think I grounded the 2000watt pure sine inverter.

42OhmsPA mentioned the bonding neutral thing in #11 up there...but didn't explain what it means.
My research hasn't been helpful.

Can you please explain what 'bonding a neutral" means?

Thank you

At exactly one place in your system, you need to connect the neutral wire to the ground/earth wire. This is a neutral ‘bond’.
Usually this is done at the generator if you’re running off a generator, inverter if it’s the primary power source, or main panel if you’re just running off of main’s power.

If you have zero ‘bonds’ the neutral and ground will not be at the same voltage, and sensitive things like furnaces will be unhappy.
If you have more than one bond, your system can do all sorts of weird things that can be hard to diagnose.