On cruise fridge failure!

[MagicalArmchair]

Heatwave in the Uk, and it’s lovely, however got back after a walk and Liz noticed the fridge was not that cool. Checked and the compressor wasn’t running. There is voltage to the unit, so it’s not a fuse or breaker or anything, it just isn’t running. It’s a BD35F Danfoss, I haven’t got a flipping LED in my stocks (why would I?) so i can’t wire up the diagnostic port.

I’ve turned it off and cleaned up the fan, that was quite dusty. Any tips? I’m leaving it for a little while to cool off, then I’ll try powering it up again.

I’m about to lose the bbq food! 

[tiger79]

Could be a failed thermostat.  It's easy enough to bridge the thermostat contacts so the compressor runs constantly - you just have to remember to switch it on and off.

[geoff]

The fridge voltage sensor is very fast , if there is a bit of muck on a connector it will drop the voltage so fast that a multimeter wont detect it . When mine did the same thing I rigged a pos and neg straight from the battery to the fridge hey presto it worked . Mine was a corroded terminal in the electric cupboard. good luck and cold beer. Geoff

[MagicalArmchair]

Could be a failed thermostat.  It's easy enough to bridge the thermostat contacts so the compressor runs constantly - you just have to remember to switch it on and off.

Good thinking, I've bridged C and T to bridge the thermostat and it's alive again. How long should I run it for? I haven't got another thermostat - I kick myself as I have an IR thermostat at home. I'll leave that on the boat in future. 

[MagicalArmchair]

https://www.amazon.co.uk/dp/B07LCJ556P?ref_=cm_sw_r_ud_dp_GBZDK1N6PFNH1NPVD2NB

Could I get something like this and put a piggyback terminal on the power input to the compressor, and then put the switch between the C and T terminals on the compressor?

I'm not sure how I would run the new thermostat wire mind you. I could just run it outside the fridge and pop it in the top for now to get me up and running.

I'll aim to have it running for around 50% of the time. Tonight it is cool, so it shouldn't get too hot. Hmmm.

[Yngmar]

That digital thing is what I've replaced/recommended on about a dozen boat fridges by now. It's vastly better than the original gas expansion thermostat.

The sensor just goes in the fridge wherever you find it most practical, in our case the center of the front wall. Then I've mounted the display in a cutout on the front panel, so you can see temperature readout and adjust easily. Works extremely well and only heard good things from the others. I carry a spare but it's never failed yet.

[tiger79]

Good thinking, I've bridged C and T to bridge the thermostat and it's alive again. How long should I run it for? I haven't got another thermostat - I kick myself as I have an IR thermostat at home. I'll leave that on the boat in future.

I'd run it for a couple of hours on, couple of hours off, and see what happens.

It's an easy job to replace the original thermostat.  I replaced mine 4 years ago, with a replacement from Norfolk Marine.  As Yngmar says, the original thermostat isn't great, but I wanted a quick and easy swap.

[geoff]

I am with Yngmar on this I too use an stc 1000 and find it is brilliant . watching the temp rise and fall is compulsive. Geoff

[MagicalArmchair]

To jury rig this for the cruise I got out my trusty gaffa tape! I put a piggy back on the positive and negative going to the fridge, and then from the C and T terminals on the fridge to the cooling connections of the thermometer...

.... and nothing... then I realise I have ordered the 220V version of it in my haste. Damn it!



Will the above set up work once I get the correct version of it?

How did you manage to get the probe into fridge? And run the cable? For now, as a jury rig, I was just going to run it outside and tape it on with electrical tape. Clearly not an enduring solution.

Do you have any photos of your whole set up please?

[Klausen]

you can follow the tubes from the compressor to the condensator plate and put the sensor into the fridge. yes, with the 12v version it works very well.

[MagicalArmchair]

Hmm even with the compressor running non stop (I've been waiting to turn it off for the temperature to get down low enough), the temperature of the fridge is not going below 14 degrees.

Does bridging C and T terminals do enough to have the compressor running? Does it need a resistor in there or something to make the compressor work harder? I worry we are murdering our next lot of food....  .

Or could it just be the fridge needs more coolant? Or is just generally on the way out?

[geoff]

Try running a direct feed from the battery . The compressor will appear to be running [condenser fan running]even if it fails the start up volt test. If you hear it try to start then fail at about 3min intervals it is probably low volts. Geoff

[marioxp]

Try running a direct feed from the battery . The compressor will appear to be running [condenser fan running]even if it fails the start up volt test. If you hear it try to start then fail at about 3min intervals it is probably low volts. Geoff

I have a strange problem with the operation of the refrigerator. Sometimes, I notice that the compressor starts up very often, what's more, as soon as it stops working, it starts right away. The temperature in the refrigerator rises, from which I conclude that it is not working properly. The temperature on the digital thermostat is raised so that the thermostat supplies electricity. I measured the voltage, and I didn't see a difference. This situation lasts for some time, then I try to turn off the refrigerator at the switch, sometimes it helps, sometimes it doesn't, there is not exact pattern.

Could it be reason a lack of gas or overheating of the compressor?

[Yngmar]

Hmm even with the compressor running non stop (I've been waiting to turn it off for the temperature to get down low enough), the temperature of the fridge is not going below 14 degrees.

How hot is the compartment with the condenser and compressor in it? You might not know this because it's the first time it's actually hot where you are, but most of us in warm climates had to enhance the removal of hot air from this compartment somehow. Easiest is leaving the door open (or half open with a cork wedged in). If the condenser unit is surrounded by hot air, it can't dump the heat very well.

[marioxp]

Hmm even with the compressor running non stop (I've been waiting to turn it off for the temperature to get down low enough), the temperature of the fridge is not going below 14 degrees.

How hot is the compartment with the condenser and compressor in it? You might not know this because it's the first time it's actually hot where you are, but most of us in warm climates had to enhance the removal of hot air from this compartment somehow. Easiest is leaving the door open (or half open with a cork wedged in). If the condenser unit is surrounded by hot air, it can't dump the heat very well.

I can confirm that it is warm in the compartment, but it also happened on colder days.

[MagicalArmchair]

Hmm even with the compressor running non stop (I've been waiting to turn it off for the temperature to get down low enough), the temperature of the fridge is not going below 14 degrees.

How hot is the compartment with the condenser and compressor in it? You might not know this because it's the first time it's actually hot where you are, but most of us in warm climates had to enhance the removal of hot air from this compartment somehow. Easiest is leaving the door open (or half open with a cork wedged in). If the condenser unit is surrounded by hot air, it can't dump the heat very well.

Thanks Yngmar. Interestingly the evaporator is icing up, however the temperature of the fridge itself stays high. I've never inspected the fridge with a digital thermometer before, so it may always have been high.

For now, until I can fix the thermostat, to preserve the food and not poison the kiddies we are running the compressor constantly (and I'll leave that cupboard open when I can) Not ideal, however, poisoning the crew would not make me popular.

Any danger to running it constantly? I've been giving it the occasional breather when I remember to switch it off. 

[Yngmar]

Any danger to running it constantly? I've been giving it the occasional breather when I remember to switch it off. 

Only to your batteries! Those Danfoss compressors don't really break.

[Keweetoo]

MagicalArmchair,
I had an issue with my compressor/fridge -part of the evaporator plate was icing up significantly and the compressor running constantly but not really getting the fridge cold. Problem was loss of gas over time such that there what was left in the system was being super cooled and hence ice forming on the entry to the evaporator plate and around the supply pipe. A gas recharge fixed the problem and no further issues. Why or how the gas is lost I don't know, but if a top up is required every few years then cheaper than replacement of the fridge I guess.

[gmatthews]

Thought I would share some of our fridge issues on our B47 with a Waeco fridge...
We had a problem where it would run almost continuously so the freezer was cold but not the fridge. This is a low gas issue. Fortunately our service guy in Gocek turkey was able to fit a gas valve in to be able to recharge it. It has a slow leak so we get it recharged every 2 years or so.
This season I found it would cycle on and off continuously in the morning when the battery was lower. I found there was 1.6V drop in the wiring to the fridge so when the battery was at 12.3V the fridge was at its 10.6V low voltage cut out. Added additional wires to the fridge and fixed!
This fridge also ices up very quickly (< 2 days), the seals seem OK. A small fan inside at the back has helped a lot with this.
GM

[diverphil]

just a thought, if the evaporator plate is icing up but not getting fridge cold is the small fan in the fridge blowing air over the plate, ie letting the plate freeze up instead of circulating the air.