Install THIS Transfer Switch to Run Your Furnace on Backup Generator Power

Thanks!

The furnace starts and then stops because it fails its (pilot) flame test during startup. There's a part called a "flame sensor" or "flame rectifier" that is energized with AC voltage and sits in the pilot flame. The pilot flame conducts a small current, and rectifies it. The return path for that small current is the grounded chassis of the furnace. The controller checks if a) the flame sensor current is detected, and b) that it's rectified (i.e. it's looking for a small dc current between the flame sensor and ground). If the flame test fails then the furnace shuts down. For that to work the furnace has to be grounded properly. Meaning that neutral and ground are bonded in one place. If neutral and ground are not bonded at all, then the ground is floating w.r.t. neutral and the flame sensor won't work reliably. If neutral and ground are bonded in more than one place then you'll get ground loops and the flame sensor also won't work reliably. If your generator has a bonded neutral then you need to switch the neutral at the transfer switch (or else you have multipe neutral-ground bonding points). If you generator does not have a bonded neutral then you don't need to switch your netural, but you do need to make sure that generator's netural and ground are connected through to your distribution panel's neutral and ground (because that's where the netural is bonded). If your generator does not have a bonded neutral and you do switch the neutral then you'll have no netural-ground bond anywhere, ground will be floating w.r.t. neutral, and that won't work either.

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Wow, I have never seen the switch anywhere but connected directly to the furnace

If possible, I would leave an existing switch either before or after the transfer switch.
Prior to would likely e the best choice, especially if the breaker or means of disconnecting utility power to the circuit is far away. This permits diagnostic troubleshooting of the transfer switch to be done w/o running back to the breaker panel.

Also… I’m not sure, but I’d guess the power inlet provides a means of disconnect for the powered item.
(in addition to the integral DPDT rocker switch and/or the old/existing disconnect switch, if you left that installed’p)

And… I always try to install a commercial 2-pole spec. grade switch at the boiler or furnace and an additional switch at the entry to the area the boiler or furnace is located. This permits a service technician to kill power at the boiler and/or the homeowner to kill power from a distance. The distant switch comes in handy when there is fire or hazard in the boiler area.

There exists a wide variety of disconnect switch PLATES.
single gang / double gang / 4” square 1900 / utility box cover / and more
Red in color with white printing:
“Emergency” / “Emergency Oil Burner” / “Emergency Gas Burner” / “Emergency Oil Heat” / etc…

Also, if wiring an alternate and distant disconnect switch, always run power TO the distant switch and from that, feed the boiler/furnace. Do NOT run a 2-cond(14/2 or 12/2 etc) and just switch the “hot” line conductor. A bunch of safety issues and w/o the neutral, EMF & RFI generation is huge on that wire run.

Thanks!

Power keeps going out so I’m going to do this. Thanks for finding the open ground issue. That would have been confusing.

⚠️ Quick Note…. I heard a rumor that this product is using the ETL listing for the power inlet as the listing # for the fully assembled product. The inlet device was manufactured by another company and supposedly all components are made by others and assembled into the single “transfer switch” device. It does have some nice reviews and is supposedly easier to wire up than the other small competing devices. (The original “green plate” and copy of that - the “purple plate” switch are a bit cramped. They are based around a 1900 4” square utility plate)

(IMHO - ETL is nothing close to UL - Underwriter Labs in the USA.
Overall, from everything I’ve seen and heard for decades now, UL is much more stringent with their testing and listing processes.

Also - in certain situations , the “trick” of bonding the “neutral” ungrounded conductor to the EGC equipment ground might be contrary to applicable codes. Please use extreme caution when modifying any electrical device unless your capable and qualified.

I’m not currently working in the field, but i am an EE and was a licensed electrical contractor doing NFPA compliance testing for fire detection and alerting systems.

Thank you for reviewing this
+ great channel!

I set this up next to my breaker box and an alternative to installing the neutral bonding plug is to tie all the neutrals (two from the switch and one from the furnace) together inside the breaker box and attaching them to the neutral bar there. Explained as the C. option in the transfer switch instructions. This worked for me when I came across the open ground issue on my generator...

I'll use your link to get me another one for my upstairs funace. I may not need it as there is an unused terminal on the rocker DPDT switch. This is what I did and tested already on the downstairs furnace. First, I am using a Champion Dual Fuel 2500 watt inverter generator with floating neutral. The only wires that are switched are the blacks - the center black connector goes to the furnace and is switchable from the line to generator black wires on the other two terminals. The White Neutrals are connected with all the other white neutrals... i.e. the neutral from generator tied direct back to the line incoming white from both the panel, so all whites are tied together. The grounds are done in a similar same way. Ground from furnace cabinet and ground from generator and ground from line side are joined together. The furance cabinet is basically bonded to the panel and the ground pin on the generator. In essence, it becomes a bonded ground generator by tying all the grounds together in the switch box including back to generators ground (making it bonded). When not in use, I use a "dummy'" femaie plug so near zero chance of having any live wires from furnace and/or panel hot. All the wires are tucked away and out of sight until needed to connect genny again. The other company (with the green box- and very proud of their product) is essentially wired the same way as the one you have. I do like the green light which indicates it's on generator is a nice touch. (all for about 1/2 as much as the other branded one and you've got a good rubber cover for that deceivingly open 3 pin connector) Thanks for the links!

If you wanted a few things on the transfer switch, say the furnace, fridge and waterheater, would you need a higher amp transfer switch? im looking into this myself and might want 3 things on the switch. also looking at using the honda e2200i

What if you needed it to be for floating neutral generator? Would you just remove 1 of the neutral wires from the transfer switch and hook up 1 neutral to the neutral bus? In the breaker panel

Any chance to get a link to that holder you designed for the bonding plug?

If you didn't connect the white wire on switch to load and just connect the 3 whites, load , feed and generator together and just tape off the 2nd white wire on transfer switch all should be ok . Then forget putting that bonding device on the Generator . Leave gen as floating neutral . Agree or disagree !

Ihave a 50 amp inlet box with interlock being installed for a Duromax 9000 inverter generator, that should run my central air and heat, correct or would I need to install one of these and use the bonding plug?

I typically will use a grounding rod, with my generator. Would I still get an open ground indication, if I install this switch?

So..... if power is out wouldn't the power to the Thermostat also be out... what would tell the furnace circuit board hey time to turn on?

Yes, yes yes what a cheap simple fix but do you realize why they leave the neutral and grounds unbonded on generators and power inverter generators because you’re supposed to technically ground your generator to a ground rod outside that’s more safer. A lot of people on here are doing what I call cheat stuff you know And although it may work at first and it may work on all these items sooner or later, it’s not gonna work for somebody else. There’s a reason why everything is left unbonded on these inverter generators and generators essentially in general like I said they want you to ground your generator or your inverter generator Which should be usually buy a solid copper wire like they do from your electrical panel that runs usually a ground rod. Every house usually has one 8 foot down in the ground, copper or aluminum, depending how old Home is, but don’t take my advice.

Don't need it !

Hi sir, Your video content is good, I hope we can have a chance to chat.