Jump to content

Fridge issue


roland elsdon

Featured Posts

We have a 12v battsfridge in our camper small domestic size which has been fantastic over the last 10 years. However when we started it this year even on mains it cycled a great deal. (Australian fridges are serious bits of kit and previously it only cycled 3 -4 times a night) now it is short cycling for a minute on and four minutes off. Obviously as you decrease temp this worsens.

i hauled it out and checked seals and condenser gave it all a good clean.

it has a computer fan under the cooling element this was seized. Ahah i said in my best british accent and sorted out a new one. (40 dollars from batts 45 dollars from the caravan shop but we need to order it or 13 dollars from china express delivery)

i replaced the fan and yes its the right rotation side up etc and off it purred.

sorted i cried in my best cockney accent. No.. minor improvements mainly explainable by overnight temps only and whether we had aircon on.(unusual)

the australian sites all say its knackered and i need a new one (1250), batts says the whole condenser motor and stat is ' one unit 700. There seems to be talk of regassing but its sealed system ( hence batts approach) (knowing some the locals it would be hacksaw off the pipe refill it and bung a bit of rubber hose on the split 400...)

any ideas camper is not in first flush of youth.

Link to comment
Share on other sites

No idea who or what 'batts' is.

 

I had a similar problem (high rate of cycling and not getting down to temp, ice box 'melting') with the fridge on the boat and it turned out to be a 'lack of voltage' - not quite sure how that would apply in your case as its on both mains and 12v but maybe worth checking tightness of connectors etc,

Link to comment
Share on other sites

How's about instead of running it on the leccy, you keep putting ice cold cans of lager in it to keep the shrimp and any other contents cool? You have to take them out and drink them regularly, replacing them with fresh ones as you go, but that's pretty much what a n Aussie fridge is for, isn't it?  Adapt and overcome mate, adapt and overcome!

:cheers:

Link to comment
Share on other sites

Airlock in the coolant circulation system? I found after a serious bump in the boat, and sometimes just when unused for long time, the whatever it is in the pipes doesn't flow. Advice to me was turn it upside down for a couple of hours, then back to the right way up, leave to settle then start it again. It's worked for me a few times. 

Link to comment
Share on other sites

4 minutes ago, Arthur Marshall said:

Airlock in the coolant circulation system? I found after a serious bump in the boat, and sometimes just when unused for long time, the whatever it is in the pipes doesn't flow. Advice to me was turn it upside down for a couple of hours, then back to the right way up, leave to settle then start it again. It's worked for me a few times. 

WARNING - only if its an absorption fridge. Try it on a compressor fridge and you are very likely to ruin it in short order. However that would solve the problem.

I suspect it is a compressor fridge from what the OP says but can not be sure. However I don't see how one could tell an absorption fridge is cycling.

My guesses are:

1. ice box door not shutting properly.

2. Faulty thermosatts

3. Probably most likely , the refrigerant has leaked out - hence talk about degassing.

 

Link to comment
Share on other sites

1 hour ago, Alan de Enfield said:

No idea who or what 'batts' is.

 

I had a similar problem (high rate of cycling and not getting down to temp, ice box 'melting') with the fridge on the boat and it turned out to be a 'lack of voltage' - not quite sure how that would apply in your case as its on both mains and 12v but maybe worth checking tightness of connectors etc,

You're too young; that's the problem.

Being a compressor fridge, I'm guessing he's referring to the late Maurice Batts who met a sticky end and was the main producer converter of Lec kit (also long lamented - not).

However it could be 'batteries' - difficult to know as I found the post somewhat convoluted.

Link to comment
Share on other sites

If it were batteries then the OP should have mentioned a warning lamp flash code or a beep code - that is unless his fridge maker has declined to fit such a feature.

I suppose we really need the voltage at the back of the fright with the compressor running pus the battery voltage taken at the terminals. From that we can make inferences about any starting voltdrop on the cables plus the likely running voltage.

I know one make of early 12V compressor fridges used a so called swing armature compressor unit and that may not prouce flash codes. I am unsure but I think it may have been Waeco.

Edited by Tony Brooks
Link to comment
Share on other sites

I can't imagine this being loss of gas. Loss of gas on a compressor fridge results in the thing running 24/7 and never getting properly cold. I've had this a few times with fridges over the decades.

In this case, the hysteresis (difference between ON and OFF) has become very small, hence the short cycling. The OP doesn't actually say if the fridge is still cold inside just that it turns ON for a minute and OFF for four minutes. Instead of ON for an hour and OFF for four hours previously. 

This suggests a thermostat problem to me. I read about modern compressor fridges having stuff like over-run timers and clever software control of the motor to limit cycling on and off but this fridge is probably too old for all that. My bet is the thermostat is failing, or the anticycling timer. Time to take it to bits and measure stuff with a DMM!

(Oops DMM = DVM.)

Link to comment
Share on other sites

If it's a 12v compressor fridge then there are plenty of cheap 12V temperature controllers on Ebay, just needs an understanding of hysteresis and knowing where best to put the sensor.

Or try a replacement thermostat, bit of a 'parts-jockey' approach without a proper diagnosis, but favourable compared to the cost of a new fridge.

Usually the mfr buys in a cheap thermostat and marks it up considerably to sell at their spares price; some parts number sleuthing can usually get the original part at a good price.

Link to comment
Share on other sites

18 minutes ago, smileypete said:

Or try a replacement thermostat, bit of a 'parts-jockey' approach without a proper diagnosis,

 

Taping a digital thermometer sensor to the thermostat sensor would be the first step in diagnosing. See what temperatures the switch is turning ON and OFF at.

If the hysteresis is really tight I bet there is some sort of anti-cyling delay timer that has stopped working. Follow the wires to find it!

Link to comment
Share on other sites

Compressor could be stalling, or the starting devise failing to disconnect the start windings, then the overheat protector cuts it off (bi-metal Klixon).

Once cool, it tries again ad infinitum. 

Link to comment
Share on other sites

8 minutes ago, Kwacker said:

Compressor could be stalling, or the starting devise failing to disconnect the start windings, then the overheat protector cuts it off (bi-metal Klixon).

Once cool, it tries again ad infinitum. 

If that were the case it wouldn’t be cooling so come on OP - is the fridge getting cold?

Link to comment
Share on other sites

2 hours ago, Kwacker said:

Compressor could be stalling, or the starting devise failing to disconnect the start windings, then the overheat protector cuts it off (bi-metal Klixon).

Once cool, it tries again ad infinitum. 

 

I am far from convinced that 12V compressor fridges have a bimetallic cut-out. I think the motors are a form of stepper motor and the protection is by electronically monitoring the motor current. Otherwise there would be no easy way to shut down on low voltage and allow the rotor speed and various voltage setting to be altered.

Link to comment
Share on other sites

6 hours ago, Mike the Boilerman said:

 

Taping a digital thermometer sensor to the thermostat sensor would be the first step in diagnosing. See what temperatures the switch is turning ON and OFF at.

If the hysteresis is really tight I bet there is some sort of anti-cyling delay timer that has stopped working. Follow the wires to find it!

Or look at the output of the existing thermostat, is it switching rapidly or constantly on?

I'd have thought if it's an overheating problem the switching would happen largely regardless of temperature setting.

There should be a service manual for the fridge somewhere, at least when running off 12V there's no electrocution hazard.

Maybe just try bridging the thermostat connections for a while if it's a simple 2 wire non electronic thermostat, and see if the compressor runs constantly.

Edited by smileypete
Link to comment
Share on other sites

Sorry for gap i wrote this last night but it failed to send , im  in gods own country for scenery but not internet 

thank you all its a compressor fridge similar to shorline but dated 1999 given our vw is 2004 the hire company  we bought it from could have had them stockpiled . As i said used to be faultless. Fault remains on mains or 12 battery is new (we are not going down that road.

i can lower the fridges temperature with the stat it then runs consistently at the new temperature with the same cycling issue. So turning it up late in day and then down again gives me 2 hrs sleep grace before it cycles again

it used to do 48 hrs running on a 100 amp hr leisure battery before the cutout i installed to prevent battery death cut in (12.15v) and yes i have checked that.

bricked i think if i want to sleep between the fridge and my head at night is  a single piece of cabinet board..

still keeps very cold but i suspect this is the harbringer of death. 

All the components are potted and i cant find where in the fridge the sensor for the stat is. As i said the manufacturer offers one solution a complete new sealed cooling pack compressor stat and heat exchanger bolt in out

i think its the gas

Oh yes 

i basicaly have a multimeter a screwdriver and a few bike tools!!!! This is what we live in. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.