Fox ESS Error Code-1 No Utility, Error Code-26 Grid Voltage Fault, Error Code-27 Grid Frequency

[Wolfenden12]

So I wasn’t looking in the right place! The breaker had tripped so I reset it and all was fine for 2 days, happened again yesterday and today. I’ll call installer tomorrow but what could it be? Seems to start when I force charge battery overnight? I also have an ashp that has been running more as it’s so cold, shall I just leave the breaker off and should I be worried?

[Dave Foster]

So I wasn’t looking in the right place! The breaker had tripped so I reset it and all was fine for 2 days, happened again yesterday and today. I’ll call installer tomorrow but what could it be? Seems to start when I force charge battery overnight? I also have an ashp that has been running more as it’s so cold, shall I just leave the breaker off and should I be worried?

If it is happening when charging it is very likely the breaker is not rated correctly or is faulty - what inverter size do you have, and can you have a look at the breaker and see what it’s rating is (B16, B20 etc.. or post a picture of the breaker)

For now leave the breaker on, once I know the rating if you have access to the inverter panel and don’t mind going into settings we can change the max battery charge current which should stop it from popping until the installer comes out.

[RobSweeney]

Hi

This error has occurred on my system which I have reported to provider. I've looked at Solar and main breaker, nothing was tripped, but switched the solar trips off and on. Still getting the error message. What steps should I take next?

Thanks

[Dave Foster]

Hi

This error has occurred on my system which I have reported to provider. I've looked at Solar and main breaker, nothing was tripped, but switched the solar trips off and on. Still getting the error message. What steps should I take next?

Thanks

The error means there is no mains voltage being recorded by the inverter, so possible a faulty MCB or RCD feeding it (try switching them off then back on again) - if that still fails to register it could be a wiring fault / loose wire in the AC connector and that is best left for an electrician to investigate.

[if42]

Hi
Newly installed KH10.5

I tried a force charge (which I am not entirely sure what this does other than charge from the grid?)

This seems to have started and then stopped, and the fault codes 1, 26, 27 are now set.

I see in the pinned / top post here that the MCB sizing may be wrong for my inverter, see attached screenshot - I think that's the MCB?!?

I tried restarting the inverters, DC off, AC off, Battery off, wait for inverter to power down, and then all back on - but it did not solve the fault states - I did not as yet flip the PV MC as shown.

Any tips welcome!

Thanks!

[Dave Foster]

Yes that is underrated, it should be at least a 50A breaker - you’ll need your installer back to fix that.

Disable any force charge you have set and then turn the breaker back on again.

You can do a temporary fix to throttle max power the batteries are charged at, you’ll need to know your battery voltage which you can find at the inverter panel in System, Battery - then once you have it you can go into the inverter settings, battery, max chg current.

The charge current is the DC amps not AC amps that’s why you need to know the battery voltage - you want to reduce the charge current to (say) 4000 watts so you divide 4000/battery volts and that will tell you what to set the max chg current to (the default is 50)

4000 watts will be approx 17A (AC) which is well within the 32A breakers limits

[Will]

in the meantime while you're waiting for your mcb to be upgraded to a larger one you can set the inverter limit to 70% so it's stays within the 32amp limit.

[reef]

I suspect this undersizing is rather common unfortunately. My installer only installed a 20A breaker on my H1-5.0-E.

It hasn't tripped in 2½ years but isn't ideal.

[if42]

Thanks very much!

I contacted the installer and they have come and changed the MCB and also the cable between the inverter and the consumer unit, which they said was also under rated.

Regarding force charging, are there "good" current rates to set or should I leave the defaults and lets the BMS handle it?