Odd Mastervolt problem

[Tracy D'arth]

Mastervolt 2000w combi charger/inverter

 

Mains input is not going anywhere, will not charge the batteries. Mains up to the connections underneath OK.

Inverter works fine apart from showing led fault code for overheating even from stone cold switch on.

 

Its not any connections, resetable thermal fuse, or duff batteries.  No signs of a burn up.

 

Any ideas please?

[Tracy D'arth]

Had a quote for shipping it back to Holland but over 10 years old they don't want to repair it. So it may be a replacement,  Any recommendations between Mastervolt, Victron and Sterling?

[MtB]

1 hour ago, Tracy D'arth said:

works fine apart from showing led fault code for overheating even from stone cold switch on.

 

On gas boilers such things will be reported to the PCB by a "negative coefficient thermistor". Fantastically unreliable and once they start going out of calibration, exactly this sort of fault results. Even though the combi is cold, the NTC is reporting its hot so the logic turns the charging off to prevent it 'overheating' even further.

 

These NTCs in boilers typically have a resistance of maybe 20kOhms at room temp, falling to say 5k at say 80c. When busted they might be 5k (or much lower) at room temp. My guess is your combi needs a new 50p NTC. 

 

[Tracy D'arth]

 

43 minutes ago, MtB said:

 

On gas boilers such things will be reported to the PCB by a "negative coefficient thermistor". Fantastically unreliable and once they start going out of calibration, exactly this sort of fault results. Even though the combi is cold, the NTC is reporting its hot so the logic turns the charging off to prevent it 'overheating' even further.

 

These NTCs in boilers typically have a resistance of maybe 20kOhms at room temp, falling to say 5k at say 80c. When busted they might be 5k (or much lower) at room temp. My guess is your combi needs a new 50p NTC. 

 

That is logical but with the complete lack of service info for these units what am I looking for? A disc ceramic?

[MtB]

4 hours ago, Tracy D'arth said:

 

That is logical but with the complete lack of service info for these units what am I looking for? A disc ceramic?

 

 

This is what it might typically look like. But if you find it, identifying it accurately might be impossible. 

 

A fine selection of them here:

https://uk.rs-online.com/web/c/passive-components/surge-protection-components/thermistor-ics/

Bear in mind though I'm out of my depth with proper electronics. Nick or DMR will be able to advise better than me. 

 

 

 

[pearley]

Or you could ask Sellweb at Tamworth if they can repair it.

[Jen-in-Wellies]

16 hours ago, Tracy D'arth said:

Mastervolt 2000w combi charger/inverter

 

Mains input is not going anywhere, will not charge the batteries. Mains up to the connections underneath OK.

Inverter works fine apart from showing led fault code for overheating even from stone cold switch on.

 

Its not any connections, resetable thermal fuse, or duff batteries.  No signs of a burn up.

 

Any ideas please?

Saw a similar fault recently on one of these. The inverter worked fine. The changeover switch from incoming mains to inverter worked fine, but the charger side produced nothing, except for the appropriate charging LED lighting up.

[robtheplod]

15 hours ago, Tracy D'arth said:

Had a quote for shipping it back to Holland but over 10 years old they don't want to repair it. So it may be a replacement,  Any recommendations between Mastervolt, Victron and Sterling?

I'm a Victron fan.. gradually changing over to them. Like how all the kit talks to each other.....

[MtB]

47 minutes ago, Jen-in-Wellies said:

Saw a similar fault recently on one of these. The inverter worked fine. The changeover switch from incoming mains to inverter worked fine, but the charger side produced nothing, except for the appropriate charging LED lighting up.

 

 

I was thinking along these lines earlier this morning. If an item of consumer electronics fails, often hundreds of them fail with the exact same identical fault so some goggling may well turn up a load of posts on other forums about this exact fault, and someone has probably already worked out the fix. 

[MtB]

 

 

And a brief google turned up this thread here with what looks like a similar fault. Also never got resolved. Looks like your Mastervolt is now a doorstop or needs posting off to Holland for repair.