PV causing error code on electric range

[shepelec]

Recieved an interesting service call.
Customer states that their new electric range shows a power error code only when the PV inverters are on line, shut the inverters off or when the sun goes down, the error goes away and the range works properly. Apparently the PV installer and the appliance service tech are at a loss.
I have been told all the voltages are within acceptable ranges and the PV system is generating at rated output.

I have not been on site yet but was hoping to get some input first beyond the usual of checking connections and grounding issues. Research shows a possibility of harmonics but usually in larger systems, this is a 5Kw array. I'll supply make and model after my site visit.

Thanks
Paul

 

[jaggedben]

It could be harmonics or power factor. Why an electric range should care about those things is beyond me.

I suspect that checking connections and grounding will not tell you anything. Unless you are going to bring instrumentation to study the AC waveform, you are probably wasting your time with a visit. And then again, unless you can supply that info to someone who actually engineered one or both pieces of equipment, probably wasting time.

You said this is a new range. I hope the customer can still return it and get a different brand. Almost certainly that would be the cheapest fix.

 

[shepelec]

Thanks for the reply.

I'm going there tomorrow to put an analyzer on the service to see exactly what the problem is.
From the research I've done it's looking like this might be an emerging issue with these systems, probably cheap inverters,
I'll post my findings. Thinking a power conditioner might be a possible solution. We'll see what the engineers have to say once I get the data.
Apparently this was a very expensive range and they aren't really interested in alternatives.

Paul

 

[ggunn]

Thanks for the reply.

I'm going there tomorrow to put an analyzer on the service to see exactly what the problem is.
From the research I've done it's looking like this might be an emerging issue with these systems, probably cheap inverters,
I'll post my findings. Thinking a power conditioner might be a possible solution. We'll see what the engineers have to say once I get the data.
Apparently this was a very expensive range and they aren't really interested in alternatives.

Paul

And of course there's the principle that correlation does not necessarily mean causation. It could be the PV system or it could be something else entirely that happens only during daylight hours.

 

[shepelec]

According to the customer, turn the PV breaker off and all is good....we will see...

 

[jaggedben]

Thanks for the reply.

I'm going there tomorrow to put an analyzer on the service to see exactly what the problem is.
From the research I've done it's looking like this might be an emerging issue with these systems, probably cheap inverters,

Well, if they are not UL listed inverters, then that's one thing. If they are merely 'cheap' but UL listed then that's a bigger issue. UL 1741 is supposed to ensure that these sort of things don't happen.

I'll post my findings. Thinking a power conditioner might be a possible solution. We'll see what the engineers have to say once I get the data.

Please let us know if you find a clear problem and solution. I'm certainly curious.

Apparently this was a very expensive range and they aren't really interested in alternatives.

Naturally. Is it an induction range or something? Again, not that I know much, but I'm a bit baffled as to why a heating appliance would care much about waveform. (If it's really so fancy maybe they can re-program it to ignore whatever is generating the error?)

 

[Jraef]

...
Naturally. Is it an induction range or something? Again, not that I know much, but I'm a bit baffled as to why a heating appliance would care much about waveform. (If it's really so fancy maybe they can re-program it to ignore whatever is generating the error?)

It's doubtful that it's the heating elements themselves that would be a concern. It might be that because newer appliances now have computerized controls, it is the power supply for the electronics that doesn't like the inverter fed source. An SMPS being fed from an SMPS can be problematic if the filtering is not done right on both sides.

 

[jaggedben]

It's doubtful that it's the heating elements themselves that would be a concern. It might be that because newer appliances now have computerized controls, it is the power supply for the electronics that doesn't like the inverter fed source. An SMPS being fed from an SMPS can be problematic if the filtering is not done right on both sides.

Hmm. Seems like with a good inverter it should make no difference. Or that a capacitor or two in the range would solve the problem. If it's a brand name inverter I'm gonna blame the range!

One point that didn't get made yet...
We don't know how old the PV system is. If the inverters are more than 10 years old and out of warranty then I would probably replace them; they would likely need replacing in the next few years anyway, and newer better models probably won't cause an issue.

 

[shepelec]

So in follow up:

I checked all the voltages and obvious things regarding the solar install and the range and came up with a big fat zero, as expected. The error code is an F68, which according the manufacturer is a high power error.
I ran the unit for 15 minutes without issue but then the owner turned the disposer on and up came the error code.
The highest voltage I saw was 123/245V. This did not change with the panels off.
This is the second range, the first range ran for 3 days at the distributor with out any issues.
The PV sys was installed in August.
The owners wife stated "This seemed start happening after someone hit a pole down the street".
I am familiar with the PV installer and they generally do a pretty good job, for the life of me I can't recall the brand name of the inverters but they are common.
My suggestion was a power quality analyzer to see exactly what was going on but they were not receptive to the cost.

Am I missing anything?

Paul

 

[ghostbuster]

Just a side note:I have had similar issues with "newer" stoves and gas furnaces when supplied with back-up generator power.

 

[ggunn]

So in follow up:

I checked all the voltages and obvious things regarding the solar install and the range and came up with a big fat zero, as expected. The error code is an F68, which according the manufacturer is a high power error.
I ran the unit for 15 minutes without issue but then the owner turned the disposer on and up came the error code.
The highest voltage I saw was 123/245V. This did not change with the panels off.
This is the second range, the first range ran for 3 days at the distributor with out any issues.
The PV sys was installed in August.
The owners wife stated "This seemed start happening after someone hit a pole down the street".
I am familiar with the PV installer and they generally do a pretty good job, for the life of me I can't recall the brand name of the inverters but they are common.
My suggestion was a power quality analyzer to see exactly what was going on but they were not receptive to the cost.

Am I missing anything?

Paul

What happens if you run the disposer with the inverter(s) off?

 

[shortcircuit2]

Just a side note:I have had similar issues with "newer" stoves and gas furnaces when supplied with back-up generator power.

Me too... with the Range. Mine was a low cost 7500watt back-up generator with manual transfer.

 

[shepelec]

Inverters off all is happy. The problem only occurs when the inverters are on and producing, no issues at night when the sun goes down.

 

[shortcircuit2]

Find out what manufacturer for the inverter for us please?

 

[kwired]

My suggestion was a power quality analyzer to see exactly what was going on but they were not receptive to the cost.

Likely the only way to see what is happening is to use equipment that can look closely to the voltage/current wave details.

Next best option may be to put some kind of power conditioning equipment on at least the power supply to the range controls, which should be less cost then conditioning equipment sized for the load of the entire range - of course you would be modifying this equipment and possibly void any factory warranty.

 

[shepelec]

The inverters are Solar Edge.

Since the customer is not willing to go forward with the power analyzer, I'm guessing I'll never get to the bottom of this issue. I have found a few instances, via Google, of RF interference with these inverters but nothing like what is happening here.
I love being the "hero" ( as most of us do) and fixing the problem but since I'm a third party in this I'm probably at a dead end.

 

[SolarPro]

The cheap and easy first line of inquiry would be to change the relationship between the CBs dedicated to the stove and the PV system. Maybe the PV system is physically interconnected near the stove CB? If so, I'd try to move the stove CB to the top of the busbar and leave the PV CB at the bottom.

There's a chance that something this simple could fix the problem.

 

[shepelec]

The cheap and easy first line of inquiry would be to change the relationship between the CBs dedicated to the stove and the PV system. Maybe the PV system is physically interconnected near the stove CB? If so, I'd try to move the stove CB to the top of the busbar and leave the PV CB at the bottom.

There's a chance that something this simple could fix the problem.

Breakers couldn't be any further apart. I did try swapping phases for the heck of it but no change.

 

[SolarPro]

Switching the phases was worth a try.

Presumably the electric range objects to the inverter switching noise. But I suppose there could also be objectionable noise associated with inverter's communications system.

If this weren't an optimizer system, I'd probably try installing an inverter from a different manufacturer. After all, the switching noise seems to vary quite a bit by vendor. But even then, I'd probably first see what happens if I swap in a new inverter from the same manufacturer. I'm not optimistic this would change anything, but it seems worth a try.

Since it's not your job, it's probably academic.

 

[PWDickerson]

The OP indicated in post #9 that the range error code was "high power". Could the issue with the range simply be caused by the inverter raising the load center bus voltage over the threshold that the range considers OK? It should be easy to determine the upper threshold from the range manufacturer. Is there monitoring data available from the inverter to check that against?