3 way Fridge working on gas not electric

[davewood]

Hi
Got the Zenith 5 2009 out of storage.
All good but:
The Thetford 3 way fridge will not work on electric.
You can feel the heat coming out of the exhaust vent on both electric and gas.
On gas it is cool ing but quite slowly.
The thermostat is turned up to max.
Any ideas?

 

[Martin_E]

Sounds like a partial blockage in n the heating matrix

 

[birdman101]

They take a time to cool. We always switch ours on the day before going away

 

[davewood]

Hi Martin
Thanks for the reply.
From further research it looks likely to be the 240v heating element, (I take it, that the same as the heating matrix) or the PCB.
I’ll do some research on replacing both.
Thinking about it, if the vented air is warm for both gas and 240v running, then it most probably not the 240v heating matrix..
Hi Birdman101, I had it running for 24 hours on 240v, warm air venting from behind fridge but no cooling on 240v.
Regards
Dave

 

[IanB1485]

Get a clamp on ammeter

https://www.amazon.co.uk/MAXRIENY-Multimeter-Resistance-Continuity-ACM91/dp/B0BY3Y855J/ref=asc_df_B0BY3Y855J?mcid=0621f13afe6e30df805846abd8fe511d&hvocijid=13909183230547661519-B0BY3Y855J-&hvexpln=74&tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=13909183230547661519&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046661&hvtargid=pla-2281435178058&gad_source=1&th=1

This has a sensitive range , then find a single mains wire live or neutral will do (clamp on ammeters don't work on 2/3 core cables) the fridge mains heater takes about 0.5A , this confirm or deny whether the heater is working, remember to switch off the fridge to take a base reading of what the mains charger is taking, usually about 0.2A with a fully charged battery.

 

[IanB1485]

Re the 'heater matrix' its a sealed , ammonia filled system , which can't be replaced. The heater is a simple electric element strapped to a vertical pipe ,along with the 12V heater element and the gas 'chimney' , surrounded by an insulation , within a steel jacket . To replace the heater elements , the fridge will have to be removed , which means disconnecting the gas , not something to contemplated unless you have the experience and kit to refit it and ensure the fridge is 'gas safe' and 'room sealed'

 

[davewood]

Hi Ian
Disconnecting the gas and pulling out the will be required, I will have to admit defeat and take it to the professionals.
I don’t think it will be the sealed matrix, as it works when it is heated with gas.
Dave

 

[JTQ]

That it works on gas means the refrigeration system functions; actually a big plus as when that cooling system fails things can get very expensive, more often than not a whole unit replacement.

Both gas and mains power work by heating a part of the refrigeration system, odd as that seems. In the case of gas, a flame creates the heat, in the mains [and DC] cases elements create the heat.

As suggested, yours appears to have a failed mains heating element, far from an unknown failure, or the element is not actually getting power.
Changing the elements whilst not overly difficult, does require both knowledge and ability.

In cases where those skills are missing then it needs to be given to a professional to replace the element or check it as these tasks involve several safety related issues.

 

[davewood]

Hi JTQ
Yes, I think it is down to the 240v heating element or the PCB.
I’m going more towards the PCB as when the 240v is selected the vented air from the exhaust is warm.
I will have to hand it over to the professionals but it’s good to have an understanding of the most probable cause.
Dave

 

[JTQ]

As you are saying the vented air is warm, surely this rather implies the heating element is working?
The cooling system ought not be able to tell how it gets heated, so if it works with the gas heating it should similarly work with the mains heating it.
Things not adding up here, unless the mains heating is for some reason not operating at the temperature it should.

 

[davewood]

Hi JTQ
Yes, you are right. Although there is discernible raise in temperature from the vent the 240v heating element may not be reaching the required temperature.
Dave

 

[IanB1485]

Davewood the element would either work or not . One point to note that if the mains voltage drops, the heating element is less effective and below 208 V RMS the fridge would switch off the heating element and declare a fault .Another point is the fridge must be level for the cooling to work effectively as there is no active pump moving the gas/liquid about to the correct places.

 

[davewood]

Hi Ian
As the fridge works when using gas, that would eliminate the - not being level fault.

I am erring towards getting a 2nd hand PCB and a new heating element fitted.

Dave

 

[JTQ]

Lean more to getting the fault cause identified, then turn to planning a targeted remedial solution.

 

[IanB1485]

Davewood yes if it works on gas then there will be no blockages (rust) inside the system. A good mobile engineer will do a quick amps pull test to check the heater element