Clicking noise from Dometic Fridge

Hi all

Only recently purchased our motorhome but right from the start have had issues with the fridge. As I drove off from the dealers in England it (or at least the wiring at the back of it) went on fire. That was before I traveled 10ft. Not a good start.

Dealer wasn't able to fix it but paid for repairs back here at LTS in Magheralin which included fitting a new PCB. All has been good since however last weekend we stayed at a site in Kildare near Athy and an issue arose while on EHU. After a period of time a fast clicking noise came from behind the control panel and it continued until I moved the thermostat knob higher or lower at which point it would stop. Within an hour the same thing would happen again. We were there for two days and traveled about in between but every time we hooked up the problem resurfaced.

I making a number of assumptions. Firstly its a relay and secondly the fridge is reaching optimum temp and trying to shut down but the aforementioned relay isn't playing ball. On returning home I plugged into my home electrics and tried to repeat the problem but now everything is working fine, 24hrs and not a click to be heard and fridge lovely and cold.

So my question is could the supply at the camp site be the problem ie low or fluctuating voltage.

LTS are happy to take a look and replace PCB again but I don't want to take it back with a problem that isn't a problem.

Any thoughts

Mal

Does the clicking sound like an igniter trying to light a flame?

Were you running an electric heater or other high electric using item, this can leave the fridge short of power on a site with low amp rating

Sounds like a power drop and the controls may have been trying to change to 12volt.
Maybe a test at home connect the van with the longest leads you can, put on all the mains systems in the van see if you can recreate the fault.

An underlying problem with a lot of campsites is the provision of a 10 amp (C10), or even a 16 amp (C16) MCB at the EHU outlet. I know some people have come to expect such a level of power here.
However, it's all very well having a 10 or 16 amp supply which permits the use of domestic appliances like kettles and heaters etc. but the downside is the overloading of the supply into the site and the resulting voltage drop, which apart from requiring the fridge to run on gas can also damage sensitive electronic equipment.
One occasion I witnessed a situation so bad the ESB fuse on the main board repeatedly blew one evening which necessitated repeated visits by the local ESB electrition to replace it. He said you could nearly make toast at the main board it was so hot and the site owner had to appeal to people to turn off electric heating in their 'vans.

A 4 amp (C4) or 6 amp (C6) in common in Europen sites which is why European motorhomes generally are gas only heating and have accommodation for two 13 kg LPG bottles.

[quote="baguette"]
An underlying problem with a lot of campsites is the provision of a 10 amp (C10), or even a 16 amp (C16) MCB at the EHU outlet.
I would hope they would have B type MCB’s and not C type.
C type are basically motor rated and only have half the loop impedance tolerance of the B type.
Each socket outlet must be protected individually by both an RCD and an MCB, or an RCBO by law

The essential difference between B and C MCB's is their performance when a large current is applied eg in short circuit conditions. A type B MCB will operate at a lower current than a type C. Typically a type B will operate instantly at about 4 times rated current while a type C requires about 10 times rated current to operate instantly.

In the event of a long term overload of say 1.5 times rated current (eg. 15amps on a 10amp MCB) then there will be very little difference in the time of operation between a type B and a type C.

See the top two graphs in the link. Short circuits operate in the vertical part of the graph (towards the bottom) while long term overloads operate in the curved section at the top of the graph.

The vertical axis on the graph is in seconds and the horizontal axis is multiples of rated current

https://www.schneider-electric…Curves.pdf

No I have not got my B and my C mixed up.
If it were my house I would get it tested to ensure that the MCB’s will operate within the permitted thresholds. Example
20 amp B rated max loop impedance 2.3 ohms
20 amp C rated max loop impedance 1.15 ohms.
If you live in a rural area, I have seen the main incoming as high as 0.6. That leaves you with 0.55 for the cable , outlet and distribution board resistances. At that stage if I was testing the installation, I’d be hoping for short cable runs to come in under these readings. Otherwise i would have to condemn it

It is common for continental manufacturers to fit C type as it lessens the likelihood of trip at plug in, which can, on occasion be an issue with B type. However their network is mainly underground, and vastly superior in earthing to ours, with much lower impedances.
It does amaze me that people say, sure it’s been grand for the last, whatever years, or sure no one in this estate ever had problems.
This is what I do for a living. It takes two things normally to go wrong for someone to get a an electrical shock.
1.the inadvertent exposure to a positive voltage
And
2 inadequate earthing or/ and inadequate short circuit / over- voltage protection

I am not saying you C type are definitely wrong,
I am saying they potentially are.
It’s advice,
I f I was inspecting the installation, then I would tell you for definite if this was the situation

Must be 12v / 230v changeover relay I suppose.

Nearly missed your post there Big Mal, my eyes had glazed over. Good man for taking it out in winter, this time next month you might fill in the curious, but concisely if you please.

Lol Sorry if I bored you Helga, but if you've got a story make it long I always say.