Fridge not working

[Daverw]

We replace probably 5 to 10 electronic stats per week, either relays failed, moisture ingress or buttons failed.

Agree with accuracy but do we need that on a boat fridge. All commercial units are fitted with them of course as they need tighter control but very few in domestic units

I fitted one last week on my boat as the mechanical one failed and I had one in my tool box, took longer the cut the square hole than wire it in

 

[ShinyShoe]

We replace probably 5 to 10 electronic stats per week, either relays failed, moisture ingress or buttons failed.

But how many mechanical stats would be replaced in the same period if they were in use.
As mechanical stats are less frequently seen in commercial setups these days and the domestic world just chucks things because getting a man in costs as much to fix as buy a nice shiny new fridge... its hard to make a meaningful comparison.

Agree with accuracy but do we need that on a boat fridge. All commercial units are fitted with them of course as they need tighter control but very few in domestic units

If you believe this article - maybe we should all worry a little more about the accuracy:: https://www.bbc.co.uk/programmes/p065bjm9
I have to say I haven't noticed me be struck down with listeria yet, but if I had the choice of a mechanical dial turned between 1 and 6 and a electronic unit... I know what I'd choose. Is there also a relative temperature issue with mechanical stats?

(The number of people I hear who say the fridge was warm so they turned the dial down to 1... ...because they assume its a temperature setting not a "scale" of coldness)

 

[LittleSister]

s there also a relative temperature issue with mechanical stats?

(The number of people I hear who say the fridge was warm so they turned the dial down to 1... ...because they assume its a temperature setting not a "scale" of coldness)

Can you explain the difference to this numpty who thought that a temperature setting was a scale of coldness?

 

[Daverw]

Most domestic fridges hold temp fairly well if door is only opened briefly and fridge shelves full, unfortunately most are not used like this, opened for longer than needed and many times in short periods. They have no forced air like commercial units so require periods on stable air to even out internal temperature. They are also sized just to hold the temp and reasonable room temps, the kitchen where we tend to put them can get quite warm and the efficiency then drops. The top opening units we tend to have on boats works quite well as little air is lost when opening and the internal air temp is most likely lower than at home more often. Our unit stays at +2 to +2.9 unless the compressor is off due to being switched off if shore power or engine off.

Domestic units last a lot longer than most people think and are normal working when thrown away and changed because of new decor etc. Changing a thermostat on one can some times make boat wiring look like a walk in the park

 

[ShinyShoe]

(The number of people I hear who say the fridge was warm so they turned the dial down to 1... ...because they assume its a temperature setting not a "scale" of coldness)

Can you explain the difference to this numpty who thought that a temperature setting was a scale of coldness?

A typical household fridge has a dial on the back of the fridge that says 1 to 6 on it. Turning it to 6 turns it to Maximum Coldness. Turning it to 1 turns it to minimum refrigeration. If it was a temperature scale you'd set it to 1 to be 1 degree C and 6 to be 6 degree C, so the opposite way round.

Most domestic fridges hold temp fairly well if door is only opened briefly and fridge shelves full, unfortunately most are not used like this, opened for longer than needed and many times in short periods .... .... the kitchen where we tend to put them can get quite warm and the efficiency then drops.

Boss - "we've designed a new fridge... it looks amazing. Look at all the shiny bits. Look at the fancy water dispenser, the icecube tray and just look at that twizzly knob..."

Test team - "we've tested your new fridge. It looks lovely but its rubbish. The icecube tray cracked when we forced it in to its hold a bit hard."

Boss - "we'll but something in the manual that says don't force it too hard. No-one will read the manual - but we won't need to replace in when it breaks because we will just say they should have read the manual"

Test team - "an your twizzly knob broke off..."

Boss - "fridge still works without it though doesn't it?"

Test team - "yes"

Boss - "Warranty says covers the material function of the fridge"

Test team "the other issue was it actually doesn't work too well if the room is a bit warm..."

Boss - "So we tell people not to put it in a warm room!"

Test team "like a kitchen?"

Boss - "Exactly!"

Test team "you probably need to add to the manual not to open the door or it gets warm inside"

Boss - "great - so we launch next week"

Our unit stays at +2 to +2.9 unless the compressor is off due to being switched off if shore power or engine off.

Sweet - is that on a manual stat?
I suppose you don't have 5 family members coming in at breakfast over 40 minutes, opening it to get milk out for cereal, for butter for toast, and the more milk for coffee. Thats 6 open and closures per person, if they all serve themselves as is the norm these days at home - thats 30 opening and closures of a fridge in less than an hour! On a boat - you probably are more organised - take out what you need at once. Keep it out while you do the cereal, the coffee and the toast and put it back in (perhaps slightly warmer) but only 2 openings!

Domestic units last a lot longer than most people think and are normal working when thrown away and changed because of new decor etc. Changing a thermostat on one can some times make boat wiring look like a walk in the park

I replaced my previous one because it was dead - didn't even try to find out why. It was 20+ years old. My current one (c 10 year old), shows no sign of anything electrical going - but increasingly plastic bits keep dropping off!

 

[Vegable]

What exactly does the control unit do?
I can understand that the compressor compresses and the thermostat regulates the temperature but what does the controller do?
Mike

 

[Daverw]

The controller can reduce compressor speed on some units but most likely switch off the compressor when voltage drops below a certain voltage, so can sense battery charging / shore power just like a VSR. Normally set via a resister on pins C and P, other than that not much, never looked in detail but as compressor is 12v you should be able to switch directly via external relay and electronic thermostat.

 

[Eeyore]

The fan worked and the electronic module got warm but fridge still not working. So probably the electronic module / pcb was faulty.

Perhaps teaching Grannie to suck eggs but...........you are aware that Danfoss controllers have a self diagnostic function?

 

[Dan Tribe]

Perhaps teaching Grannie to suck eggs but...........you are aware that Danfoss controllers have a self diagnostic function?

No, I wasn't aware of that. How does it operate? I didn't see any reference in the manual.

 

[Eeyore]

On newer models, there is an LED fitted. With older ones, disconnect the thermostat and connect a small LED to the small positive (+) and the 'D' terminal of the controller - it will flash an error code if the compressor fails to start. 1 flash is low voltage, 2 indicates the fan is drawing over 1amp, 3 is a compressor error (could still be low voltage), 4 and 5 are compressor faults.

 

[Dan Tribe]

On newer models, there is an LED fitted. With older ones, disconnect the thermostat and connect a small LED to the small positive (+) and the 'D' terminal of the controller - it will flash an error code if the compressor fails to start. 1 flash is low voltage, 2 indicates the fan is drawing over 1amp, 3 is a compressor error (could still be low voltage), 4 and 5 are compressor faults.

OK, thanks I understand now, I shall save these codes for future reference.
My new fridge has this function built in but the old one didn't. It's not very well explained in the manual and would have been nice to know before demolition. I expect a fridge man would have known that if only I could have found one prepared to work on yachts.