Jump to content

Fridge Behaviour


noether

Featured Posts

We have a 12v fridge, over the last 6 months or so it's gone off on a couple of occasions, both times the problem was found to be a loose connector/plug shook unplugged type things. 

 

This morning I got up early, went to make tea and found that the fridge was off - the light comes on, but it wasn't cold in there, and everything in the freezer compartment is soggy. 

 

So I hope it's just another loose connector, I put on my man hat and go and start fiddling with wires, plugs, connectors etc. I check back on the fridge, and........nothing. Still not on. I pull the fridge out, fiddle with those wires too, and still, nothing. 

 

I leave it for a little while, and go and do something else. While doing said thing, I hear the hum of the fridge - it has come back on. 

 

Since then, this pattern has been repeating - I hear the fridge hum for a few seconds, and then nothing again. 

 

I'm ashamed to say that I have no idea whether this is normal. I never paid attention to it before when it was 'working', so now that I'm listening out for it, I have no recollection whether it used to come 'off and on' like this, or whether it was on all the time (ie making a constant noise). My feeling is that it always produced a quiet hum, but now when it's 'off', it makes no sound at all. 

 

Does anybody have any clue what this is/how worried I should be/what I can or should do about it? 

 

Thanks. 

 

Link to comment
Share on other sites

43 minutes ago, MtB said:

Flat battery.

 

The fridge turns OFF when battery voltage gets too low. The batts rest and recover a bit of voltage which the fridge then detects is high enough so it starts again, then the voltage rapidly degrades and the compressor once again turns OFF. There is a red LED supplied with the Danfoss compressor which gives error reports. Two flashes every couple of seconds is "voltage too low", IIRC, if yours has the LED fitted.

P.S. Try starting your engine or putting the domestic batt on charge. If the fridge starts working normally with the higher charging voltage, this gives you a clue.  

 

 

Ah, ok, thanks. We're actually plugged into the mains at a marina at the moment, does that make a difference, would running the engine help? 

 

Is the compressor going to be at the bottom around the back of the fridge? Will it be obvious? I'm sorry for the noddy questions, but this really isn't my area, 'Learning about domestic electrics' is on my ever expanding to-do list that I never get around to. 

 

Right now I'm sat near the fridge, and it seems to be permanently 'humming' again, rather than doing nothing or 'stop starting' without me having done anything (of course, I have now just jinxed it so I'm sure it will go off again as soon as I post this). 

Link to comment
Share on other sites

8 minutes ago, noether said:

 

Ah, ok, thanks. We're actually plugged into the mains at a marina at the moment, does that make a difference, would running the engine help? 

 

Is the compressor going to be at the bottom around the back of the fridge? Will it be obvious? I'm sorry for the noddy questions, but this really isn't my area, 'Learning about domestic electrics' is on my ever expanding to-do list that I never get around to. 

 

Right now I'm sat near the fridge, and it seems to be permanently 'humming' again, rather than doing nothing or 'stop starting' without me having done anything (of course, I have now just jinxed it so I'm sure it will go off again as soon as I post this). 

Being plugged in certainly helps but you do have a battery charger running don't you?

Link to comment
Share on other sites

1 minute ago, noether said:

As far as I know, yes,

 

Well the evidence suggests you don't!

 

The art of fault tracing in very creative. One has to imagine situations that could cause the symptoms observed, then set about checking and testing to rule in or rule out the things imagined. I've done the first bit for you, but I can't do the actual testing. For that, you'll either have to employ someone or roll your sleeves up and investigate how learn how to check for each of the things I suggested, if you get my drift. 

 

So yes, the compressor is the black roundy-shaped thing in the base of the fridge round the back. It will almost certainly be the Danfoss BD35 model compressor, so start by having a google for the manual for it. When you find it, see if I am right about that error code. Then have a look at the back of your fridge and see if the LED has been fitted. If not, there are other ways.

 

E.G. buy yourself a cheap digital multimeter so you can measure voltages (ebay, about a fiver). Then use it to measure the voltage on the terminals on the compressor, and see if the voltage is above or below what the compressor needs according to the manual you found earlier. 

 

Feel free to come back and ask as many questions as you want. There is tonnes of expertise on here and a huge willingness to help anyone with the inclination to learn.

 

 

Link to comment
Share on other sites

9 minutes ago, noether said:

 

As far as I know, yes, although now you've got me worried. 

 

(in case you hadn't figured, I'm greener than Kermit). 

We all figured! 😉

 

Do you have a way of telling the charge on your domestic batteries?

 

If not, get a voltmeter and test the batteries.  If you're on a battery charger, or your batteries are being charged in some other way (solar), the volts will read somewhere above 13v.

Link to comment
Share on other sites

3 minutes ago, doratheexplorer said:

If you're on a battery charger, or your batteries are being charged in some other way (solar), the volts will read somewhere above 13v.

 

Not if the charger is busted/not working, which is what several of us here are probably thinking...

 

 

 

 

Or rather, the other way around. I'm anticipating the voltage turning out to be about 11.5v, which will illustrate the charger is not charging.

 

 

Link to comment
Share on other sites

7 minutes ago, MtB said:

 

Well the evidence suggests you don't!

 

The art of fault tracing in very creative. One has to imagine situations that could cause the symptoms observed, then set about checking and testing to rule in or rule out the things imagined. I've done the first bit for you, but I can't do the actual testing. For that, you'll either have to employ someone or roll your sleeves up and investigate how learn how to check for each of the things I suggested, if you get my drift. 

 

So yes, the compressor is the black roundy-shaped thing in the base of the fridge round the back. It will almost certainly be the Danfoss BD35 model compressor, so start by having a google for the manual for it. When you find it, see if I am right about that error code. Then have a look at the back of your fridge and see if the LED has been fitted. If not, there are other ways.

 

E.G. buy yourself a cheap digital multimeter so you can measure voltages (ebay, about a fiver). Then use it to measure the voltage on the terminals on the compressor, and see if the voltage is above or below what the compressor needs according to the manual you found earlier. 

 

Feel free to come back and ask as many questions as you want. There is tonnes of expertise on here and a huge willingness to help anyone with the inclination to learn.

 

 

The voltage on the compressor terminals is an irrelevance, its fed by an electronic sequencing module, not steady DC.

 

You need to measure the voltage on the wires the fridge is connected to whilst the motor is starting up.

  • Greenie 1
Link to comment
Share on other sites

1 minute ago, Tracy D'arth said:

The voltage on the compressor terminals is an irrelevance, its fed by an electronic sequencing module, not steady DC.

 

You need to measure the voltage on the wires the fridge is connected to whilst the motor is starting up.

 

Hair splitting!

 

I meant the voltage on the input terminal block on the compressor, which connects to the sequencing module which is part of the integrated compressor asembly.

Link to comment
Share on other sites

We've got a new member here who admits to being green, so lets keep things simple:

 

Possible culprits:

 

1.  Flat battery - test with voltmeter.

2. Thin wires to fridge causing voltage drop - test with voltmeter in the wires going into the fridge.

3. Buggered fridge.

4.  Loose connection somewhere.

 

noether needs to eliminate the first two options before doing anything else.

  • Greenie 3
Link to comment
Share on other sites

The battery says 'normal' and '14.4v' (it looks like anyway, kinda hard to see, but it's the highest), and I think it's quite new. 

 

The reason I ask about the compressor is because the fridge is very awkwardly situated (I know right, on a canal boat, who would have thought), and I don't want to keep pulling it out and pushing it back without a good reason, particularly when it's kinda, sorta, working again. 

 

I might try turning the engine on for 10 minutes just to see if it makes any difference to anything. 

Link to comment
Share on other sites

6 minutes ago, doratheexplorer said:

We've got a new member here who admits to being green, so lets keep things simple:

 

Possible culprits:

 

1.  Flat battery - test with voltmeter.

2. Thin wires to fridge causing voltage drop - test with voltmeter in the wires going into the fridge.

3. Buggered fridge.

4.  Loose connection somewhere.

 

noether needs to eliminate the first two options before doing anything else.


If the OP has had the fridge a fair bit longer than 6 months and it’s been ok, couldn’t no2 be eliminated?

 

And if the OP has access to mains electricity why not plug the fridge direct to 240v to test the fridge? If it works no3 can be eliminated.  

Link to comment
Share on other sites

1 hour ago, noether said:

The battery says 'normal' and '14.4v' (it looks like anyway, kinda hard to see, but it's the highest), and I think it's quite new. 

 

The reason I ask about the compressor is because the fridge is very awkwardly situated (I know right, on a canal boat, who would have thought), and I don't want to keep pulling it out and pushing it back without a good reason, particularly when it's kinda, sorta, working again. 

 

I might try turning the engine on for 10 minutes just to see if it makes any difference to anything. 

When you say "the battery says", what exactly are you looking at?  A battery monitor?  A voltmeter?  Something else? 

 

14.4v is a reading you should get while the battery is actively charging,for example when you've just turned on the battery charger or started running your engine.  After a few hours, the battery charger should drop into float mode and read around 13.2v.  So a 14.4v reading is odd if you're plugged in and have been for a while.

  • Greenie 1
Link to comment
Share on other sites

12 minutes ago, doratheexplorer said:

When you say "the battery says", what exactly are you looking at?  A battery monitor?  A voltmeter?  Something else? 

 

14.4v is a reading you should get while the battery is actively charging,for example when you've just turned on the battery charger or started running your engine.  After a few hours, the battery charger should drop into float mode and read around 13.2v.  So a 14.4v reading is odd if you're plugged in and have been for a while.

 

I'm looking at a blue box! 😄 It says 'charger' on it, tbh it's quite difficult to see, it's in a dark difficult to reach corner and there are lots of wires and such in the way.

 

I am intrigued what the relationship is between running the engine and the battery - obviously running the engine charges the battery, but doesn't being plugged into the mains do the same thing? I've checked the physical mainline connection, and the 'Shoreline' and 'AC Available' lights are both on, so I'm pretty certain that isn't the problem, but does running the engine do something additional that the mains power doesn't do?

Link to comment
Share on other sites

12 minutes ago, noether said:

 

I'm looking at a blue box! 😄 It says 'charger' on it, tbh it's quite difficult to see, it's in a dark difficult to reach corner and there are lots of wires and such in the way.

 

I am intrigued what the relationship is between running the engine and the battery - obviously running the engine charges the battery, but doesn't being plugged into the mains do the same thing?Yes. I've checked the physical mainline connection, and the 'Shoreline' and 'AC Available' lights are both on, so I'm pretty certain that isn't the problem, but does running the engine do something additional that the mains power doesn't do? Not really in terms of battery charging.  Typically a battery charger puts out fewer amps than an engine alternator.  An engine running will commonly heat your water tank directly, a battery charger can supply power to an immersion to heat water.

 

Link to comment
Share on other sites

Is the friidge still in warranty, if so get in touch with the supplier before you do anything else.

 

The compressor motor is controlled by a thermostat. Does turning the thermostat up to a higher (or maximum) setting make the compressor spring into life. Thermostats can go faulty or out of calibration, and are replaceable sometimes at minimal cost. If the compressor runs and the fridge doesn't get cold then you need specialist services to fix it.

 

If it is a '240v only' unit, and you are sure you have reliable supply to your socket, (which sounds likely if the internal light always comes on) then get in touch with the manufacturer customer services dept.

Link to comment
Share on other sites

4 hours ago, Mad Harold said:

Possibly the wiring is too thin causing voltage drop.

There is a formula for calculating the correct thickness of cable for the distance from battery to appliance,which unfortunately I don't have to hand.

 

Just for 12v compressor fridges, it is 1sq mm of conductor cross-sectional area for each metre of run between battery and fridge. Use the same size cable for the negative.

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.