Inverter install - Reverse Polarity??

[Jinxer]

It is grounded! Next.......

[s/v Jedi]

Originally Posted by Jinxer

It is grounded! Next.......

So you have a conductor that is connected to the inverter housing at one end and to a solid ground like rod or equicalent at the other end? A grounded cord to the stove doesn't count of course...

If ground is okay, then neutral and hot are swapped or the inverter does not ground neutral. The error indication means that there is voltage between ground and neutral.

cheers,
Nick.

[Jinxer]

Yes I have a Grounding Rod in the ground.....

So if I am understanding you correctly... you are saying that the previous poster that said that neutral and ground must be connected is true.. ONLY this must be accomplished via the inverter... not manually?? Cause mine blew up when I tried to connect them? So apparently there are such inverters that automatically connect the neutral and ground out there I just have to find that one and that will solve my problem? Am I understanding this correctly??

[DeepFrz]

I am understanding that you really need to hire a qualified electrician to check out and complete the install of your system. The statement "cause mine blew up ... " convinced me of that. You are playing with deadly stuff.

[Jinxer]

Thanks for your concern, but I am searching for solutions here, please stay on topic. I am not as illiterate as I might sound concerning electric. I knew from my knowledge that connecting the ground to neutral would be bad news... but when NOTHING makes sense concerning this inverter and why it is not working.. I figured I would attempt some of the suggestions. I am not here sticking a spoon in an electric socket, so no need to worry about me.

Everything is hooked up correctly and working exactly as it should when it comes out of the inverter. It powers other stuff like my outside lights etc. Just gives a reverse polarity when connected to my furnace.

[capn_billl]

The long and short of it is the reverse polarity light can only be caused by a few things,

1. hot, (AC) on either neutral or ground - You hooked up something wrong, or the heater has an internal short.

2. Open neutral - corroded connection, or you hooked up something wrong.

3. Open Ground - either the furnace is not correctly grounded to the inverter, or the inverter is not correctly grounded., or you hooked up something wrong.

If you are blowing fuses, you need to take a big step back, and pull out a voltmeter, and double check ALL connections.

If grounding the neutral, ... ANYWHERE, blows a fuse, (neutral should be at ground potential anyway, remember?), You have hot on the neutral, which is exactly what the light is warning you of.

Abraded wire insulation, check where it goes through panels, (you used electricians nipples, right? They have a plastic inner liner to prevent chafing).

Check with inverter manufacturer. Most houses are wired for 208V - split phase, the neutral is the phase splitter, and tied to ground at the main panel. You use the outside lines for 208, and 1 phase to neutral for 120Volts.

Most inverters are 120VAC, 1 phase, NO NUETRAL. Both outputs are 1/2 of the 120VAC. One of them is arbitrarly picked to be the "neutral" by the inverter manufacturer, and grounded in the inverter.

As the inverter uses the incoming AC to "sync" the AC output you should follow their recommendations on where and how the neutral is connected and whether it should be grounded before or after the inverter.

Wiring on a boat and a house are very different. If this is a house installation a wiring forum would be better consulted.

I am curious about the wattage of the furnace, and the inverter, as most house electric furnaces are 10KW or better, and 208VAC.

A common failure of house furnaces are debris, or insect landing between elements and supports causing a resistive short to ground, or the wire in the element can break or deform and bridge to the frame. If the short is near the end of the element the furnace will continue to work, but the frame will be slightly "hot". The short can also make and break as the element heats up and expands.

If the furnace is connected to a typical house utility power you will never notice it unless you actually go into the attic and touch the frame of the furnace with a meter, (unless you by some chance use a ground fault breaker on the furnace, "not likely").

BUT if the furnace is powered by a local source like an inverter, this current leakage can cause detectable problems, (My inverter has built in ground fault detection).

The above advice about hiring a professional should not be lightly ignored. Electrical looks easy, but wiring regs have been developed by years of experience by engineers with a great deal of knowledge of the fundamental properties of electricity.

[hellosailor]

Jinxer, I think the call for an alectrician was not a commnet on your skills, but rather pointed toward the fact that home wiring can be so cleverly screwed up in some many ways and places by all the previous owners and workers.

Ideally you have, of course, three wire not two wire all through the home, with all the appropriate grounds and everything wired correctly. But it rarely happens that way unless you have new construction by a very good team.

It should be sufficient to trace/test your furnace wiring back to the main panel, make sure that is correct, and then use the manual for the inverter to see how they have set up neutral/vs/ground and what they suggest for the correct application here. In maine or rv use, they might be combined. In home use, separated. I'd check the inverter manual and then confirm it is wired as it should be--sometimes things aren't set up right when they ship. Then confirm the wiring to the furnace is proper.

And if everything looks right but still is wrong (without blowing more fuses) sometimes the best thing is to call the electrician, who usually knows what is normal in your area and how to spot problems. An hour of their time, a cautious day of your time...either one may work.

[Jinxer]

Thank you very much for your reply...

I do owe an apology to previous poster about my unit being grounded.. it seems I missed the word "Housing" when I read it. My inverter is grounded.. however the case was not grounded. So once I did that.. the reversed polarity went away.. So I am sorry I dismissed your idea...

HOWEVER.. now there is a NEW problem. The furnace now shows that it is getting the correct electric etc.. the lights on the furnace are showing as Normal operation. So I turned the thermastat to on and it said calling for heat and the thermastat clicked and then.... NOTHING. The motor doesnt kick on the heat never comes. So is there any insite as to why it would be doing this? I tried to call Lennox and they refuse to help the homeowner. I just would like to know this is a fixable issue before I spend the $100 for a tech to come out for trip charge just to say "Nope" lol. I dont mind paying a technician if it can be fixed or solved.

Thanks everyone for your HELP.. We are almost there.. and even tho I dont have a boat.. thanks for helping me out.

[s/v Jedi]

Originally Posted by Jinxer

Thank you very much for your reply...

I do owe an apology to previous poster about my unit being grounded.. it seems I missed the word "Housing" when I read it. My inverter is grounded.. however the case was not grounded. So once I did that.. the reversed polarity went away.. So I am sorry I dismissed your idea...

HOWEVER.. now there is a NEW problem. The furnace now shows that it is getting the correct electric etc.. the lights on the furnace are showing as Normal operation. So I turned the thermastat to on and it said calling for heat and the thermastat clicked and then.... NOTHING. The motor doesnt kick on the heat never comes. So is there any insite as to why it would be doing this? I tried to call Lennox and they refuse to help the homeowner. I just would like to know this is a fixable issue before I spend the $100 for a tech to come out for trip charge just to say "Nope" lol. I dont mind paying a technician if it can be fixed or solved.

Thanks everyone for your HELP.. We are almost there.. and even tho I dont have a boat.. thanks for helping me out.

There you go, unit was not grounded, like the 99% of cases like it. No problem about dismissing what I wrote... 99% of members here do that haha

Now to your new problem... in 99% of the cases your inverter or the batteries feeding it don't have enough umpfff to power what you try to power with it. You would need to monitor both the battery DC voltage and the inverter output AC voltage while switching on whatever it is you try to switch on (not clear to me at all). Also monitor the inverter error indicators.

ciao!
Nick.

[hellosailor]

Lennox, like many manufacturers, probably supports their franchised dealers by refering all calls to a dealer. So the dealer can make a profit on it.

Odds are that your inverter simply does not have neough power to start up the furnace motor and heating coils at the same time. Motors are usually inductive loads and they take much more power to start than they do to run. Heating coils also are probably a purely resistive load and appear as a dead short when they are first turned on, which may not please the inverter.

What is the maximum rated power of the inverter?
What is the maximum power required by the furnace motor?
What is the maximum power required by the heating coils?

Let's first see how the math works.

Personally, I wouldn't expect solar panels to an inverter to work powering an electric heating system. You'd need an awful lot of power or a terribly small heating system and in either case you'll have no heat as it gets cold at night, unless you've also got batteries in the system.

Solar hot water systems are proven more efficient and cheaper, and they can store heated water to keep you warm at night.

Just so you're aware of the options, if the numbers add up to "unfeasible".

[Jinxer]

What is the maximum rated power of the inverter? 2400 Watts peek -1200 Watts continuous

What is the maximum power required by the furnace motor? 11.3 Amps for the 1 sec start up.. after that 580watts

What is the maximum power required by the heating coils? No heating coils.. this is not an Electric furnace.. it uses natural gas, only the blower is electric

Let's first see how the math works.



Let me know how the math adds up.. I really apprecate your help and not giving up on this

[hellosailor]

"11.3 Amps for the 1 sec start up.. "
That could be your killer right there. 11.3 amps at (presumably?) 117 VAC, which is what the nominal 110/120VAC is normally, means you need 1325 watts to start that motor. If the inverter is not pure sine wave but the motor requires a sine wave, if there's some inductance issue or either device is slightly off spec...if there's some voltage drop in the cables feeding the inverter or the batteries (you do have batteries, not just solar, don't you?)...any of that would make it marginal or unable to start.

You might try using a voltmeter and ammeter to see just how far that systems "crumps out" under the starting load, to try to pin it down further. Using a clamp-on ammeter will be safer than inserting one into the 110v line, but I'd start by seeing how much power the blower motor pulls when it actually starts from the mains power, and then see if the inverter really can supply that much, as it is configured/installed.

[donradcliffe]

Having just bought a condo with a non-functional furnace, I had to learn how to trouble-shoot gas furnaces. A lot depends on how old the furnace is--naturally the older ones are easier to fix. I had the furnace guy out for $80, he said I needed a new pilot assembly for $300. I went to Google and found out that the pilot light builds up crap on the sensor which needs to be cleaned off, and fixed it myself for nothing.

My older furnace has does not have an electric circuit board and would probably run on an inverter, but I don't know about the newer ones being compatible with modified sine-wave inverters. If you are off-grid you might hook up a portable generator to see if the furnace works on it.

[Jinxer]

Originally Posted by hellosailor

means you need 1325 watts to start that motor.

Well since this inverter is 2400watt peek, doesnt that mean it could handle that initial 1325watt startup?

Originally Posted by hellosailor

If the inverter is not pure sine wave but the motor requires a sine wave

I have seen this alot in my recent research.. how can I tell if my inverter is a sinewave or not? And what makes a sine wave different? Does it make the electric cleaner? For example normal outlet shows 60hz outta my inverter shows 61.5hz. Does that make the electric too dirty?

Originally Posted by hellosailor

if there's some voltage drop in the cables feeding the inverter or the batteries (you do have batteries, not just solar, don't you?)...any of that would make it marginal or unable to start.

there is no detectable drop in voltage and yes I have Batteries to store the power. When I put my meter on the inverter I show and constant 117

[capn_billl]

If it doesn't say "pure sine wave inverter" in clear bold letters on both the inverter and the front page of the instruction manual, then it's not a pure sine wave inverter, but a "modified sine wave inverter", (square wave inverter).

A pure sine wave inverter in that wattage is going to be some big bucks. I've tried to use several different brands, and wattages of inverter for a big inductive motor, like the blower on your furnace, In all cases only when I went to a pure sine wave inverter was I able to make it work.