Furnace Ignitor Not Working on Generator

[Kyngfish]

Hi All,

Been caught up in these winter storms and I got the interrupter kit installed to my panel to be able to put power in my home from my 6500 watt generator. A little background on my home, most of it runs on gas, dryer, oven, range, water heater, furnace. 2300 sq foot home, and the Portland weather is generally pretty mild so my furnace isn't all that beefy. A Trane XL80 with a 1/3 hp motor on the blower running on a 20 amp circuit. Runs fine with the power on.

While on the generator though, it would do something funny. The thermostat would call for heat and it would start up and heat the house, the first time. Then once it hit temp it would shut off.

The second time the thermostat called for temp, I would see the ignitor fire up, but then it would power down and get an ignitor error (9 flashes) on the furnace. When I would pull apart the panel and toggle the gas switch on and off (no idea if this actually did anything) and put it all back together, it would fire fine again.

Now the power is back on, and the furnace is working 100% fine, so clearly there is no ignitor issue.

But I want to set up the generator for a more permanent solution, and want to resolve this. The generator is of the ground-neutral bonded type. 6500 startup watts. Grounded with a post into the ground, wired from the 25 amp 240v plug to a 25 amp 2 post breaker in the panel. Ground and neutral are also bonded at the panel. I've read 100 posts about grounding, dirty power, sine waves - just wanted to see if anyone had come up with a concrete solution.

Best.

 

[NETexas]

Do you have a Nest thermostat? I could run mine fine on a generator until I got a Nest.


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[Hot shot]

Don’t know if this pertains to your situation but I have a gas kitchen range. I’ve been running generator for going on 6 days due to ice storm. The oven part will not heat. What I think is going on is the igniter is not reaching the proper temperature to allow the gas valve to open. It’s getting hot, I looked under the bottom tray and seen it glowing but maybe not quite hot enough. I wish it had a pilot light like they used to make them

 

[rlitman]

Don’t know if this pertains to your situation but I have a gas kitchen range. I’ve been running generator for going on 6 days due to ice storm. The oven part will not heat. What I think is going on is the igniter is not reaching the proper temperature to allow the gas valve to open. It’s getting hot, I looked under the bottom tray and seen it glowing but maybe not quite hot enough. I wish it had a pilot light like they used to make them

It's the same issue. The fail-safe nature of the gas valve hot-surface-igniter system depends on clean electricity. A circuit monitors the current flowing through the HSI, and shuts the valve if it isn't good enough. The harmonic distortion from generator power may be enough to prevent it from thinking that the igniter is working properly.

 

[Kyngfish]

People use generators to power their houses right? is there a solve for this other than buying a totally other generator? Can I clean up the signal somehow? Also, odd that it works on the first ignition EVERY time, but not the second, then fine after a reset. Is there something about the overall heat of the ignitor? I'm stumped.

 

[finn]

Rlitman has it right. Your generator isn’t providing “clean” power to the furnace control board.

 

[Terry D]

I just had the pretty much the same thing happen the other day. I was doing a service change and brought a small harbor freight inverter 2000 watt honda clone generator to keep his gas furnace going. The furnace tried to come one, but stopped. I was getting 8 or 9 blinks. It was saying the hot and neutral was switched. I switched them, but nothing changed. Homeowner was worried the generator ruined the board, but once I restored power, all was good. It could be a bonding issue inside the generator

 

[Kyngfish]

Do you have a Nest thermostat? I could run mine fine on a generator until I got a Nest.


Sent from my iPad using Garage Journal

I have an ecobee. I had a nest thermostat that I'm convinced was effing with my AC function somehow and I've never had issues with the ecobee so far, but who knows.

 

[Kyngfish]

I just had the pretty much the same thing happen the other day. I was doing a service change and brought a small harbor freight inverter 2000 watt honda clone generator to keep his gas furnace going. The furnace tried to come one, but stopped. I was getting 8 or 9 blinks. It was saying the hot and neutral was switched. I switched them, but nothing changed. Homeowner was worried the generator ruined the board, but once I restored power, all was good. It could be a bonding issue inside the generator

Generator is showing good as far as grounding, it IS bonded sort of twice, once at the panel and once at the generator, I suppose since the generator is really for panel use I can unbond it and then modify a cut up extension cord to bond in a pinch, but I don't know how that would be causing an issue.

Wondering if anyone has found any solutions tho.

 

[Terry D]

Generator is showing good as far as grounding, it IS bonded sort of twice, once at the panel and once at the generator, I suppose since the generator is really for panel use I can unbond it and then modify a cut up extension cord to bond in a pinch, but I don't know how that would be causing an issue.

Wondering if anyone has found any solutions tho.

Just came across this. This could have been my problem. I had no reference to ground. The wiring to the furnace was just 2-wire romex

https://everythingwhat.com/do-you-h...out any connection to earth,earth from the AC

 

[510ebl]

Have you checked voltage and frequency at the furnace? While trying to ignite the second time?

I wouldn’t rule out THD. My water heater wouldn’t run on my conventional generator either. Runs fine on the new invertor type.

 

[Hot shot]

My generator is not grounded to anything in the ground
Wonder if that would help

 

[Hot shot]

It's the same issue. The fail-safe nature of the gas valve hot-surface-igniter system depends on clean electricity. A circuit monitors the current flowing through the HSI, and shuts the valve if it isn't good enough. The harmonic distortion from generator power may be enough to prevent it from thinking that the igniter is working properly.

What is the hsi

 

[rlitman]

What is the hsi

Hot Surface Ignitor.

 

[wyliesdiesels]

Generator is showing good as far as grounding, it IS bonded sort of twice, once at the panel and once at the generator, I suppose since the generator is really for panel use I can unbond it and then modify a cut up extension cord to bond in a pinch, but I don't know how that would be causing an issue.

Wondering if anyone has found any solutions tho.

this is dangerous. you do NOT want the neutral bonded in more than one place. it will cause neutral current to flow on the EGC.

When a portable generator is used to power a house, the neutral bond needs to be removed.

if you want a quick way to restore the bonding for standalone use, making a bonding plug, where you connect neutral and ground together with a jumper wire, and plug it into one of the generator receptacles.

My generator is not grounded to anything in the ground

Wonder if that would help

you mean like a grounding electrode?

wont do anything at all here. remember, grounding electrodes are for shunting lightning to earth, limiting voltage potential to earth and for shunting high voltage electricity when primary lines contact secondary lines.

BTW your generator SHOULD have a connection to earth via the EGC that connects to the main service panel and thus the GEC that goes to the rods at your panel....

 

[Hot shot]

Yes it does

 

[Kyngfish]

back to the question at hand - does anyone know if a voltage regulator would fix the frequency issue?

 

[wyliesdiesels]

back to the question at hand - does anyone know if a voltage regulator would fix the frequency issue?

nope. A VR regulates the voltage and is not the circuitry needed for frequency correction

 

[AP514]

FREQ/Hrz is on Enegine speed correct ?...or are you talking THD ?

 

[AP514]

back to the question at hand - does anyone know if a voltage regulator would fix the frequency issue?

Are you talking THD or Hrz ?
Engine Speed can change your Hrz.
AVR for the Voltage...and a lot of them can not be adjusted (mine included)

 

[Kyngfish]

nope. A VR regulates the voltage and is not the circuitry needed for frequency correction

Got it, will ANYTHING compensate for the engine speed? Would going up to a larger generator help it hold steadier? Say up to 7500 watts from 5500 watts?

 

[Kyngfish]

also, why does it light up the ignitor the first time and never the subsequent times?

 

[wyliesdiesels]

sounds like the governor is not regulating well

what brand and model generator do you have?

 

[sms1974]

also, why does it light up the ignitor the first time and never the subsequent times?

your problem is possibly / probably two fold...

Yes there some correlation with the generator supplying "clean" power its actually called a sine wave. we've seen this problem several times. The new equipment on the market has very sensitive electronics. this also goes along with the people that have experienced problems with the Nest thermostats.

The second part of your issue has to do with the way your furnace works. your model furnace has an "80 volt" igniter. the way these worked the first time the furnace had a call for heat it would light the igniter with a full 80 volts, on each cycle after it would drop the voltage by a percentage. after it had a failed ignition it would bump voltage back up and set that as the igniter voltage. The idea was to extend the life of the igniter by using the lowest voltage necessary. it was one of those ideas that worked great on paper but was somewhat problematic in real life.

I suspect the problem your having with it working on the first cycle but not on subsequent cycles is related to the ignitor voltage variance combined by a generator voltage or hertz rate variance...

some electronics just don't like generators...

 

[dogdog]

I am surprised no one have come out with a inverter plugin for these generators... not inverter generators, just a converter that change it to AC --> DC --> clean AC.

 

[slow]

I am surprised no one have come out with a inverter plugin for these generators... not inverter generators, just a converter that change it to AC --> DC --> clean AC.

I have something similar I built for mine. an APS-55 55 amp 13.8v regulated power supply that charges a deep cycle optima battery and connected to the output of that is an Xantrex 1000 watt pure sine inverter with GFCI plug. I use it for 2 purposes, 1 to run the fridge when the generator is not running and second (if needed) it would clean the power for sensitive items. In my case I lose a lot to the conversion, one could keep it all high voltage and possibly lose less in the conversion the way a VFD would work.

 

[dogdog]

Xantrex are good stuff... usually solar power stuff...

but they don't take generator output power or alternator output power. 5000Watt would have cost an arm an a leg... well over $2000 maybe not the first born... I did look into those when I was interested in solar power and independent grid stuff..

what I was saying was ... we know inverter generator operated this same way... dirty AC --> DC --> Clean AC... I am surprised no one have a kit to build a plugin converter on the generator to put out clean AC. Hint hint wink wink, don't forget the dogs that give you this idea if you are marketing for one lol...

 

[dcg9381]

Some experience with this. I suspect the same thing as Finn and Rittman. These basic generators often provide a "grid like" signal. When you look at it under a oscilloscope, it the power curve is a set of squares - usually called "modified sine". It's not as smooth, and certain equipment won't accept these signals.

If you've ever tried daisy-chaining UPS (Battery power supplies) - they often won't work together for the same reason.

It *could* be a generator running off frequency (too fast or too slow RPM) - but I haven't seen that happen as much. Most volt meters can check frequency, so this is pretty easy to catch.

IF you have a buddy with a "inverter generator" - give it a try and see if it solves this problem.

 

[larry_g]

It was asked above, what is the voltage output? This last outage I found that my generator was putting out ~100 vac. It ran most stuff but some items refused. I have a new regulator on order.

lg
no neat sig line

 

[dcg9381]

Agree. Measure both line voltage and frequency. IF those are close, you've likely got something fancy that doesn't like the modified sine wave.

 

[Fasthotrod]

back to the question at hand - does anyone know if a voltage regulator would fix the frequency issue?

No, it would not.

There are two different things in play here. They are related, but independent of each other.

The voltage regulator looks at the output voltage of the alternator and makes adjustments to the field current, increasing or decreasing the magnetic energy in the rotor to adjust the voltage.

The engine governor controls the engine speed (RPM) and speed is directly proportional to frequency output. (Hertz, or Hz for short.) The speed at which the engine should run is dependent on the type of alternator used, specifically the number of poles inside the alternator:

F = NP/120

F = Frequency
N = Speed of Rotation
P = Number of poles
120 = Converting Minutes to Seconds. (60 seconds in a minute)

So a 3,600 RPM generator with 2-poles:

F = (2 * 3,600)/120

F = 7,200/120

F = 60Hz

A 4-pole 60 HZ generator would run at 1,800 RPM.

Any time you place a load on an alternator, you get a dip in frequency as well as a dip in voltage. Here's what happens:

The engine governor will see the change in speed and increase fuel to compensate for the drop in speed... much like your car's cruise control when you head up a hill. The engine accelerates towards 60 Hz and will likely pass it, then will reduce the throttle to drop back to rated speed. If you were looking at the waveform, you would see frequency droop, then a slight overshoot, then settle back down to rated frequency.

The voltage regulator will see the drop in voltage and increase field current to bring the voltage back up to nominal. The voltage regulator is typically much faster than any changes with the engine speed, as it's electronic vs. mechanical.

On cheaper units, these devices to not 'talk' to each other. They work independently. On some of the higher priced units (typically not portable units) the voltage regulator has a, "Volts per Hz" function that will see both the voltage and frequency, and when it sees the drop in frequency it can 'dial back' the field current, reducing the effective load on the alternator/engine and allowing it to recover speed. As speed/Hz increases, the voltage regulator will increase current to the field to bring the voltage back into tolerance.

One thing that I try and remind people of is that a portable generator has a specific task in mind... providing power and maintaining portability. This means that the engineers that design it have to make compromises... often times it's quality of output vs. overall weight. One way to have better regulation of speed is to simply have a big, heavy flywheel. The rotational mass of the flywheel will retain rotational energy during a transient event, but the engine will need to work harder to get it up to speed, and push more power if/when the load is high enough to pull the frequency out of tolerance.

Another way is to have a larger engine with more rotational mass, or one that has a more consistent power application like a Diesel vs. Otto (gas/propane) system. More info here: https://vivadifferences.com/difference-between-diesel-cycle-and-otto-cycle/

A lot of modern electronics are sensitive to changes in both frequency and voltage. Most home appliances are designed with a rock solid commercial power input in mind... so if you have a newer home, you will likely want to invest in a generator that is designed to put out clean power to your home.

Hope this helps.

Mark

 

[AP514]

That is why I have my generator set to 61.5 Hrz with No-Load (3690RPM)

 

[Noltz]

I am surprised no one have come out with a inverter plugin for these generators... not inverter generators, just a converter that change it to AC --> DC --> clean AC.

They do. Probably OP's easiest solution is a sufficiently sized UPS for his furnace. They're a few hundred bucks but provides PC-safe power, brown-out protection and a few minutes at least of black-out protection. I'm not certain about codes though.

That is why I have my generator set to 61.5 Hrz with No-Load (3690RPM)

Mine is just about 60 as well, 62 I think unloaded, 61 with a 3k load. Buddy bought an identical genny and it too reads 62 on the panel.

 

[Jeepster04]

I had the exact same issue with my trane xl-80, sortve...

Power went out for 4 days and I ran it off a friends 7500 watt conventional crazy loud generator, no issues what so ever.

Power went off again and I tried to run it off my honda inverter generator, it never even tried to light and gave me the 9 flash error of bad igniter. I figured I screwed something up and just waited for the power to come back on. All is well now.

I found it strange a crappy loud conventional generator would run it but my honda inverter generator wouldn't. Ive not checked the HZ on the honda but I ran my tv and DVR today while the power was out again...

 

[slow]

I had the exact same issue with my trane xl-80, sortve...

Power went out for 4 days and I ran it off a friends 7500 watt conventional crazy loud generator, no issues what so ever.

Power went off again and I tried to run it off my honda inverter generator, it never even tried to light and gave me the 9 flash error of bad igniter. I figured I screwed something up and just waited for the power to come back on. All is well now.

I found it strange a crappy loud conventional generator would run it but my honda inverter generator wouldn't. Ive not checked the HZ on the honda but I ran my tv and DVR today while the power was out again...

My Honda EU2000 puts out 60 volts on the hot and 60 volts on the neutral measuring between hot/neutral and ground. If you make a bonding plug to bond the ground to neutral, it makes 120 volts on the hot when measured from hot to ground. This could be part of the issue your seeing.

 

[wyliesdiesels]

My Honda EU2000 puts out 60 volts on the hot and 60 volts on the neutral measuring between hot/neutral and ground. If you make a bonding plug to bond the ground to neutral, it makes 120 volts on the hot when measured from hot to ground. This could be part of the issue your seeing.

something wrong with your generator then

the bonding of neutral has nothing to do with the voltage the alternator head generates.

 

[jlv03]

I am surprised no one have come out with a inverter plugin for these generators... not inverter generators, just a converter that change it to AC --> DC --> clean AC.

I think you have just described an "on-line" or double conversion UPS.

https://en.wikipedia.org/wiki/Uninterruptible_power_supply#Online/double-conversion

https://new.abb.com/ups/systems/single-phase-ups/powervalue-11-rt

 

[Hot shot]

When my power came back on the oven igniter started working again

 

[dave*99]

something wrong with your generator then

the bonding of neutral has nothing to do with the voltage the alternator head generates.

Are you sure there is something wrong with the generator? If his generator is NOT bonded, then neutral is floating.

So when the measures from Hot to Ground he gets 60V.
Neutral to Ground also 60V.

If he bonds Neutral to ground - 120V from hot to neutral. And I suspect zero from neutral to ground.

 

[slow]

from my research all Honda 120 inverter generators operate like this with a floating neutral. (except the 240 volt eu6000-eu7000 models) generating 60 volts with a 120 volt differential between the hot and neutral.