Dometic fridge

[Robinhood]

..on the Tec Tower I was playing with, the control panel fascia could be removed by removal of locating screws (a number of which were in the control knob recesses, and only apparent after removing the knobs).

 

This gave access to a black plastic surround/box containing the PCB. I believe the wires can be removed from this without splitting the box (they are 'edge plugged' at the rear). Access to this one was difficult, until an earth tab on a short wire was removed from the top of the fridge (a bit fiddly) at which point (removing locating screws) the whole thing could be pulled forward just about enough against the wiring (and the wires presumably unplugged).

 

The PCB containing box would then need to be split (and I'm not sure if this is simply tabbed retainers, or screwed together - my final diagnosis was after later pondering).

 

The maintenance/overhaul instructions indicate that it is designed to be done in-situ, and I believe it, even if it's fiddly.

[Noody]

In the case of my fridge you would have to partially remove it to get the pcb out, the main reason the pcb can't be removed in situ is because the converter has screwed a piece of trim over the top of the pcb case which wedges it firmly in place. If it hadn't been for that lack of foresight then yes, you could remove the pcb after removing the hob above it so you can unscrew and release the 240 volt supply which is stopping the pcb case being pulled foreward.

 

Moving slightly to one side on the repair problems, how about the cost of spares for these units.

 

I recently replaced a pcb on a dehumidifier, this particular machine has many controls for humidity levels and fan speeds. £56 plus postage. Ok, it doesn't work on gas or 12 volts.

 

A piece of pvc hose about 9 inches long that drains water from somewhere to be evaporated in a container at the rear of the fridge is over.

 

The burner jet is £20 and the burner assembly without igniter lead and flame failure is over £70 but that includes a jet.

 

Is it me in my old age that is loosing grasp of reality ?

 

I just had two ABS rings sent from France for £35 including postage,

 

Returning to the possibility of a repair on the pcb, is it possible that an electronics workshop could diagnose and replace failed parts and use their brains by increasing the values of the failed parts ? Is this possible after they received the pcb in the post ?

 

When my EBL failed I posted it up to the north Wales workshop we all know about, it was diagnosed, repaired and returned within a week. Excellent.

[Robinhood]

...there are an awful lot of firms around that offer to do PCB repairs; a web search will pull a good number up. Many offer a mail-order service.

 

There are two issues with such an approach (which shouldn't deter you under many/most circumstances). The first is, how easy is the repairer going to find it to diagnose the fault? (especially in complex circumstances) - if a particular component (e.g. a known relay) is the prime suspect, then this might well be simple. The second is how easily is a replacement component (or equivalent) obtained? A significant amount of most PCBs is going to consist of standard, relatively easily replaced components. If, however, the failure happens to be in a programmable chip with proprietary coding embedded, this is far from simple - for these, the original customer is likely to be the only source, and a replacement PCB is often the only solution.

 

....and while I'm at it, I'll apologise (only slightly, not profusely ;-) ) to Brian as, having returned home my current 'van has the fridge wired *entirely* conventionally, with the power supplied through the EBL from the vehicle* battery. (This is a far from common arrangement on the 'vans I've had in the past, but I've now checked the fusing on this one).

[Brian Kirby]

Apology slightly accepted! :-D I do have a residual niggle with Richard's proposal for working around his duff thermostat 12V switching relay.

 

This is just a don't know issue, so I'm wondering if anyone else does?

 

Richard proposes to cut the D+ switched 12V fridge heater supply between the EBL and the fridge terminal block and insert a manual switch into the circuit. He will then wire from the manual switch direct to the 12V heater element. It isn't yet clear whether he will leave the return (-) from the heater element as is, or also replace this and, if so, where he will terminate it. Don't know whether that may be an issue to consider.

 

However, my main query concerns the (now redundant) PCB mounted switching relay, and why it is PCB mounted. From Robin's description in his parallel posts about his friend's PCB, it seems the relay is soldered in. I therefore assume there are connections onto the PCB to/from that relay.

 

The two spade connected wires visible in the photo are the feed/return for the 12V heater element, per the fridge wiring diagram. So, we have switched 12V via the EBL (so live only when the engine is running). This terminates onto the 12V connector strip (usually top rear of the fridge: terminals A and B). The power is then taken to the fridge PCB within the fridge wiring, and thence (via the PCB?) to the energy selector switch and the thermostat switched relay, and then on to the heater element.

 

The PCB mounted relay could, therefore, have been mounted anywhere between the connector strip and the fridge heater element, which is also at the rear of the fridge. All it needs is power via the energy selection switch, its operating signal from the thermostat, and an onward connection to the heater element.

 

So, question, why is that relay incorporated into, and moreover soldered to, the PCB? More importantly, with Richard's work around, will the loss of power to the PCB circuits, as presently energised from the connector strip, cause a malfunction elsewhere? Is this relay so mounted just for assembly line convenience, or is there some further 12V feed via the PCB? Purely my ignorance of PCBs, but isn't 20A quite a heavy current to put through a PCB? I thought they were usually used for quite small currents and ultra low voltages. Just puzzled, that's all! :-)

[747]

Noody - 2017-11-05 4:15 PM

 

These varied comments are very positive for me, and helpful. I'm still committed to my proposed simple work-around. The Dometic control was manual, I will have a manual control with an LED LIGHT.

 

I took the pcb out for a looksee on the basis of Alan's recommendation. I couldn't replace that failed switch and it may not be the switch, maybe another component. Either way as I keep saying there is a lot of history attached to this failure.

 

If I had an electronics workshop within driving distance I might consider a repair, I won't consider a replacement Dometic pcb and it's not just the money. I live in rural north Pembrokeshire, the benefits of lining where I live are huge but there is a price to pay. When my Truma boiler needed help it was a three day trip to Derbyshire.

 

I have just completed a test rig for my workaround, it works perfectly. The Dometic is in my workshop connected up to gas, 240 volts, 12 volts low current supply and 12 volts high current supply from its own battery source supported by a charger. I was surprised how quickly the 12 volt element heated up. I'm even getting my head around temperature control in the case I need it.

 

Those Dometic fridges are a thousand pounds, I expect more even though my van is 13 years old because this problem emerged around 2006 on the various forums.

 

Going back to my work-around, how many of us drive without a stop for more than four hours, even if it's just for a pee. I just cannot see a problem with the work-aroun but I am inviting comments.

 

You state that a replacement fridge would be around £1,000. You are badly mistaken.

 

I have the 7 series AES Dometic fridge/freezer which was a problem early this year on our first outing. On gas, it stopped working. As it was 11 years old and had never been serviced I dropped the van into Tyne Valley Motorhomes (the supplying Dealer and Dometic Approved). They said they had found the fault (a Thermistor) and I gave the go ahead to fit a new one. This did not solve the problem and they said they had spoken to Dometic Technical who said I needed a new fridge/freezer. Tyne Valley quoted me a price of £2,350 including fitting cost of £150. The replacement would be an 8 series fridge/freezer as 7 series are discontinued. I initially (very reluctantly) agreed but thought about it overnight and told them the following morning not to go ahead and that I would come and collect the van.

 

I brought it home and started my investigation (I was a multi-skilled Engineer before retirement and was fairly confident that the fridge/freezer was repairable). It took me 10 minutes to discover that 240V was OK, 12V was OK but it did not automatically revert to gas when the engine was switched off (the light on the gas section of the indicator did not illuminate). My fridge functioned OK when manually switched to gas. The fridge had been giving off a smell on gas on the last trip the year before so I cleaned the burner and rodded out the flue. I now have a good working fridge that kept the contents cool, even through the very hot spell of weather we briefly had this year.

 

My problem is on the PCB and is an intermittent fault because on a couple of occasions, it has automatically reverted to gas when the engine is switched off. It could be something like a dry joint on the soldering and will be a bugger to locate. I think I will leave as is and manually switch over if the gas indicator light is not illuminated.

[Robbo]

747 - I thought there was a time-delay of 15 minutes or so between switching the engine off and the gas fridge firing up when on AES.

 

A safety feature to stop blowing yourself up (and others) when filling with fuel at a petrol station.

[Noody]

Brian Kirby - 2017-11-06 11:58 AM

 

 

 

So, question, why is that relay incorporated into, and moreover soldered to, the PCB? More importantly, with Richard's work around, will the loss of power to the PCB circuits, as presently energised from the connector strip, cause a malfunction elsewhere? Is this relay so mounted just for assembly line convenience, or is there some further 12V feed via the PCB? Purely my ignorance of PCBs, but isn't 20A quite a heavy current to put through a PCB? I thought they were usually used for quite small currents and ultra low voltages. Just puzzled, that's all! :-)

 

Its a good point Brian, and I still cannot see why you are concerned with my work-around. This 12 volt supply to the 12 volt element had failed when I bought the van. The previous owner, like many others just used gas rather than the questionable effect of a new pcb to solve the problem without it returning.

 

So, it hasn't been working for 9 years. When I'm using the fridge and traveling I only need the 12 volt element powered during travel time and it's only going to work on 12 volts during travel time so why do I need to rely on complicated electronics when a mechanical switching mode will no doubt outlast the two years warranty on a new pcb that may also have parts not up to the job.

 

If you are thinking that the inherent fault that stopped the relay (Switching devise) from working may pass-on this fault to other parts eventually then don't you think this may have happened by now ? In any case, my work-around is so simple that its easy to abort and buy a new pcb in the event I get further failures.

 

I fear you are complicating things, the 12 volt element is just a simple resistive circuit and as pointed out less of a problem than a lightbulb in terms of high current at switch-on, certainly less than many domestic appliance that are manually switched.

 

In the case of caravan towers I have noted that others have made a similar work-around though haven't needed to use a switch because their 12 volt circuit only works when they plug into the tow vehicle and turn the engine on. In my case I use the van regularly without needing a fridge so I need to cut the supply from the EBL.

 

I do appreciate you sharing this but just cannot get my head around your concerns other than it won't be ORIGINAL. I changed quite a few things in this van that weren't original, like altering the wardrobe so the Truma boiler can be removed for service. I would rather blame Hymer Group for that than carry the burden of me fiddling with things for the love of it.

[Noody]

I just got to thinking about that Electrolux 3 way box fridge I used to use when I was tent camping. I owned it until it started to look scruffy but never had any problems.

 

The gas operation worked in the same way as gas hob in the home with simple thermocouple for flame failure and a manual piezo igniter.

 

240 volts just worked and when I was traveling I plugged the 12 volt plug into my cars 12 volt socket that only worked when the engine was running.

 

Back to the RM 7361 fitted in my Burstner I have decided on a new position for the manual 12 volt X 20 amp switch. Just above the grey facia plate is a strip of that flimsy but mostly effective and lightweight faced plywood. I shall replace that with a piece of beech other solid timber that matches the colour of the interior wood-effect. This strip being solid will take the 20mm X 38mm switch body which will be placed just alongside the grey plastic facia of the Dometic fridge.

 

[747]

Robbo - 2017-11-06 12:55 PM

 

747 - I thought there was a time-delay of 15 minutes or so between switching the engine off and the gas fridge firing up when on AES.

 

A safety feature to stop blowing yourself up (and others) when filling with fuel at a petrol station.

 

You may be right about the 15 minute delay on gas ignition ...... but the indication that it has changed from 12 volt to gas should be immediate. In my case, when the gas indication did not come up, I gave it a lot longer than 15 minutes before deciding it was faulty. ;-)

[aandncaravan]

Noody, So I am right in thinking that the plan is to allow all the electrics to work exactly as they should, except that only after they have 'kicked in', do you then connect the element to the circuit by your switch?

 

The reasoning, presumably, being to reduce arcing/load in the relay/circuits by locating the new switch between the Element and PCB so that the standard electronics have all 'settled' by the time you connect the Element to those circuits?

 

If that is the case then you should extend the reliability handsomely.

 

 

Only caution I would add is that you maybe uprate your switch and relay as we are seeing 'well used' vehicles drawing over 13amps on a element which 'shouldn't'.

 

Not long ago we saw a newish Fridge/Freezer, standard fit Rimor, drawing 17amps yet all connections, etc. were good. This was running off connectors rated at 20amps.

 

Suggest you think about a 20amp Maxi fuse (lower resistance, better connectivity) and double check all connections are clean and tight on the wiring to the elememt?

 

 

 

 

 

 

[Noody]

Is it Alan ? Hello.

 

Thanks for the positive view on my work-around. I'm taking the 12 volt element circuit away from the Dometic electronics completely because I wouldn't even trust a £150 replacement pcb.

 

If there was a workshop like yours that specialised in these Dometic electronics in the same way you specialize in the EBL then I would be happy for a repair.

 

The two element connections to the pcb are removed and plugged into a blade fuse holder with 15 amp or as you suggest 20 amp sub-circuit-protection although I did run a test with a 15 amp fuse.

 

Then I will manually switch one of the heavy conductors just before the connection to the connection strip so I can break the supply when I'm not using the fridge on days out or maybe as a manual temperature control.

 

There are occasional opinions from those who have used a similar workaround that the 12 volt element doesn't work well enough to require temperature control, this is a concern because I found that the element heated up very quickly. More so than on gas.

[Alanb]

Brian Kirby - 2017-11-06 11:58 AM

 

Apology slightly accepted! :-D I do have a residual niggle with Richard's proposal for working around his duff thermostat 12V switching relay.

 

This is just a don't know issue, so I'm wondering if anyone else does?

 

Richard proposes to cut the D+ switched 12V fridge heater supply between the EBL and the fridge terminal block and insert a manual switch into the circuit. He will then wire from the manual switch direct to the 12V heater element. It isn't yet clear whether he will leave the return (-) from the heater element as is, or also replace this and, if so, where he will terminate it. Don't know whether that may be an issue to consider.

 

However, my main query concerns the (now redundant) PCB mounted switching relay, and why it is PCB mounted. From Robin's description in his parallel posts about his friend's PCB, it seems the relay is soldered in. I therefore assume there are connections onto the PCB to/from that relay.

 

The two spade connected wires visible in the photo are the feed/return for the 12V heater element, per the fridge wiring diagram. So, we have switched 12V via the EBL (so live only when the engine is running). This terminates onto the 12V connector strip (usually top rear of the fridge: terminals A and B). The power is then taken to the fridge PCB within the fridge wiring, and thence (via the PCB?) to the energy selector switch and the thermostat switched relay, and then on to the heater element.

 

The PCB mounted relay could, therefore, have been mounted anywhere between the connector strip and the fridge heater element, which is also at the rear of the fridge. All it needs is power via the energy selection switch, its operating signal from the thermostat, and an onward connection to the heater element.

 

So, question, why is that relay incorporated into, and moreover soldered to, the PCB? More importantly, with Richard's work around, will the loss of power to the PCB circuits, as presently energised from the connector strip, cause a malfunction elsewhere? Is this relay so mounted just for assembly line convenience, or is there some further 12V feed via the PCB? Purely my ignorance of PCBs, but isn't 20A quite a heavy current to put through a PCB? I thought they were usually used for quite small currents and ultra low voltages. Just puzzled, that's all! :-)

 

Brian,

 

It is normal practice for relays operated by signals generated on a PCB to be mounted on the same PCB. This is a matter of manufacturing simplicity. You may as well ask why 9 relays are mounted on the CBE DS520 Distribution Board in my PVC. This board also has 4 off 6mm studs for battery and charger connections, and hence carries larger currents than a fridge PCB.

 

I have however seen some PCB mounted relays which while having the coil connections soldered onto the PCB, the concacts are presented on 0.25" blade connectors.

 

I see no problem with the propesed workaround, other than slightly reduced operational convenience.

 

We have on occasion forgotten to switch from 240V to 12V on our MES fridge. Not a serious problem in UK. Looking back the fridge in our first MH was probably made in 1990 or earlier. I cannot recall the model number, but it had separate switches for mains and 12V. The gas ignition was a piezo button.

If you took the 12V switch out of that fridge and mounted it just above the fridge, would that have been significantly different to Richard's proposal?

 

Alan

[aandncaravan]

Noody, It is Allan, but I answer to almost anything.

I have sent you a PM, but these guys used to do this sort of thing and we have worked with them before and they are good :

http://www.arelectronics.co.uk/contents/en-uk/d3_Electronic_Repairs__Modifications.html

 

 

 

 

[Noody]

Thanks for the link Alan, I contacted them immediately and after a long conversation we agreed that a proposed repair/modification whilst possible was out of their immediate expertise.

 

When I mentioned that there was a lot of history attached to this problem the gentleman I spoke with (We didn't introduce ourselves) thought there may be potential but he would need a fridge rather than just the pcb.

 

And thank you for validating my workaround.

 

Taking the fridge out has been on the back-burner for a few years, other than dealing with this electronics/electrical problem I needed to inspect the installation and check the flooring. Once again I found poor workmanship though I suppose it was adequate. I didn't buy a Hymer group vehicle to end up with adequate.

 

 

[Alanb]

Noody - 2017-11-07 8:00 AM

 

Is it Alan ? Hello.

 

The two element connections to the pcb are removed and plugged into a blade fuse holder with 15 amp or as you suggest 20 amp sub-circuit-protection although I did run a test with a 15 amp fuse.

 

Then I will manually switch one of the heavy conductors just before the connection to the connection strip so I can break the supply when I'm not using the fridge on days out or maybe as a manual temperature control..

 

Richard,

 

Please allow me to clear up what may be a misunderstanding on your part.

 

There is Allan of aandacaravanservices who has a vast wealth of practical experience on repairing motorhome and caravan electrics, the ther are the Alans including me.

 

However that is not my reason for posting. You mention as quoted, removing the 12V power connecters from the PCB and installing a fuse holder perhaps with a 20A fuse. While it is not wise to generalise, the standard Electrobloc wiring would include a 20A inline fuse dedicated to the fridge,close to the vehicle battery. I suggest that you may not need a second fuse. Why not use two male blade connectors to connect to the leads removed from the PCB? (Sleeving the connections with heat shrink sleeving is advisable.) The connectors could then connect via short leads directly to your new switch.

 

Alan

[Noody]

Thanks Alan.

 

Yes, I realized you were a different Alan. I already have been a customer of Allan who repaired my EBL a couple of years back.

 

Alan, it's a good idea. I will check the circuits and as you suggest no point in replicating fuses which is also my point about the replication of relays just adding to the possibility of failure.

 

Just as an after thought, whilst I'm not competent dealing with modern electronics I am an old and retired radio ham with a lot of experience working over 3000 volts so insulation is a first. I always use heatshrink when the opportunity arises and understand basics like conductor sizes.

 

In the case of this fridge the final conductor sizes were too small compared to the carcass conductor, these heated up during tests.

 

 

(Edted: Allan of A and N has a double LL) Keithl

[monique.hubrechtsgm]

Does that Manual over ride by passes the auto PCB board? About the smell of gas of autogas, LPG bottles of propane which come from gas wells and associated oil and othrrs have no smell to a human being. What are you actually smell? There is methane gas in a cow,s outlet which can be fired, but metane gas has no smell.Have technical gases have smell additive?

[monique.hubrechtsgm]

I must say that the above handyman are impressive on the dometic fridge. And for sure: knowledge is usefull only if it is also implemented from theory into practise.

[Noody]

Hello Monique. Yes, this modification bypasses the electronic board (PCB) I have tested the work, it works very well without a problem.

 

Regarding gas smell, I don't understand so please explain.

 

When the fridge is fitted into the motorhome the rear of the fridge must be isolated from the living compartment so any escape of gas or fumes can escape through the low placed ventilation.

 

I hope this helps.

[Keithl]

Noody - 2017-11-07 6:03 PM

 

Hello Monique.

 

Regarding gas smell, I don't understand so please explain.

 

I think Monique may have been referring to this thread on a possible gas leak...

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Calor-gas-leak-/48149/

 

Keith.

[Brian Kirby]

Noody - 2017-11-06 1:01 PM

 

Brian Kirby - 2017-11-06 11:58 AM

 

 

 

So, question, why is that relay incorporated into, and moreover soldered to, the PCB? More importantly, with Richard's work around, will the loss of power to the PCB circuits, as presently energised from the connector strip, cause a malfunction elsewhere? Is this relay so mounted just for assembly line convenience, or is there some further 12V feed via the PCB? Purely my ignorance of PCBs, but isn't 20A quite a heavy current to put through a PCB? I thought they were usually used for quite small currents and ultra low voltages. Just puzzled, that's all! :-)

 

Its a good point Brian, and I still cannot see why you are concerned with my work-around. ......................

For three reasons Richard. First, you pointed a question at me in your first post. Second, you sought opinions on your proposal. Third, we all try to help each other, so I'm asking questions partly to try to tease out any possible unforeseen sangs, and partly to learn more from the replies of others who know more than I do. It ain't originality I'm concerned about, just that it works reliably.

[Brian Kirby]

Alanb - 2017-11-07 10:44 AM

 

Brian Kirby - 2017-11-06 11:58 AM

 

Apology slightly accepted! :-D I do have a residual niggle with Richard's proposal for working around his duff thermostat 12V switching relay.

 

This is just a don't know issue, so I'm wondering if anyone else does?

 

Richard proposes to cut the D+ switched 12V fridge heater supply between the EBL and the fridge terminal block and insert a manual switch into the circuit. He will then wire from the manual switch direct to the 12V heater element. It isn't yet clear whether he will leave the return (-) from the heater element as is, or also replace this and, if so, where he will terminate it. Don't know whether that may be an issue to consider.

 

However, my main query concerns the (now redundant) PCB mounted switching relay, and why it is PCB mounted. From Robin's description in his parallel posts about his friend's PCB, it seems the relay is soldered in. I therefore assume there are connections onto the PCB to/from that relay.

 

The two spade connected wires visible in the photo are the feed/return for the 12V heater element, per the fridge wiring diagram. So, we have switched 12V via the EBL (so live only when the engine is running). This terminates onto the 12V connector strip (usually top rear of the fridge: terminals A and B). The power is then taken to the fridge PCB within the fridge wiring, and thence (via the PCB?) to the energy selector switch and the thermostat switched relay, and then on to the heater element.

 

The PCB mounted relay could, therefore, have been mounted anywhere between the connector strip and the fridge heater element, which is also at the rear of the fridge. All it needs is power via the energy selection switch, its operating signal from the thermostat, and an onward connection to the heater element.

 

So, question, why is that relay incorporated into, and moreover soldered to, the PCB? More importantly, with Richard's work around, will the loss of power to the PCB circuits, as presently energised from the connector strip, cause a malfunction elsewhere? Is this relay so mounted just for assembly line convenience, or is there some further 12V feed via the PCB? Purely my ignorance of PCBs, but isn't 20A quite a heavy current to put through a PCB? I thought they were usually used for quite small currents and ultra low voltages. Just puzzled, that's all! :-)

 

Brian,

 

It is normal practice for relays operated by signals generated on a PCB to be mounted on the same PCB. This is a matter of manufacturing simplicity. You may as well ask why 9 relays are mounted on the CBE DS520 Distribution Board in my PVC. This board also has 4 off 6mm studs for battery and charger connections, and hence carries larger currents than a fridge PCB.

 

I have however seen some PCB mounted relays which while having the coil connections soldered onto the PCB, the concacts are presented on 0.25" blade connectors.

 

I see no problem with the propesed workaround, other than slightly reduced operational convenience.

 

We have on occasion forgotten to switch from 240V to 12V on our MES fridge. Not a serious problem in UK. Looking back the fridge in our first MH was probably made in 1990 or earlier. I cannot recall the model number, but it had separate switches for mains and 12V. The gas ignition was a piezo button.

If you took the 12V switch out of that fridge and mounted it just above the fridge, would that have been significantly different to Richard's proposal?

 

Alan

OK. Thanks for that Alan. Yer lives and yer learns! :-D

[Noody]

Brian, I was concerned you had spotted or considered a problem I hadn't foreseen so rather than my comment sounding like I needed help maybe it sounded like criticism ? For that we need to blame the difficulties of communication by text rather than face-to-face communication that usually includes expression and tone changes.

 

This issue has been well aired, in your case with considerable attention to details I had to keep back-tracking on for fear of missing something and I thank you for that.

 

There have to be a number of other Dometic fridge owners who could find this thread useful because the various issues have been batted back-and-forth particularly if I can complete the project with a few photos and a positive report on the functioning.

 

As if we haven't aired enough I have another question, does anyone know why the fridge 12 volt element supply shows 2.3 volts when the supply isn't energized and the engine isn't running ?

[Brian Kirby]

Noody - 2017-11-08 6:40 AM.............................As if we haven't aired enough I have another question, does anyone know why the fridge 12 volt element supply shows 2.3 volts when the supply isn't energized and the engine isn't running ?

I assume the permanent 12V supply to the fridge is live (usually from the leisure battery - powers the fridge control panel - and interior light, where fitted)? I also assume the meter jumps from 0V to 2.3V and is either digital, or doesn't have a "sticky" analogue pointer? So, guessing, possibly leakage on the pcb from the control circuit to the heater circuit? Any capacitors on the fridge? Back-feed due to poor earth/ground elsewhere on the fridge? If nothing should be live, including the control circuit, have you tried unplugging all the fridge feeds at the EBL to see if the 2.3V still shows?

[Alanb]

Richard,

 

Given your declared background , I assume that you are using a digital multimeter for your measurements. Please remember that these devices have a high input impedance - possibly in the megohm range.

 

If not already done, try if possibe disconnecting the fridge element supply close to the fridge and check both ways.

 

Alan