Just not chilling

Preamble

My fridge has broken. Only just realised. I think it has been broken ever since I came back. I came back home from Thailand recently, and for about a month I was wondering why my food was going off, the margarine just turned to water (literally), all the meat went off very quickly, beers didn’t chill, milk curdled and the cheese absolutely stank. The light came on, when I opened the door, and the warning LEDs where all green, so I assumed that it was working. Then I thought to myself that I hadn’t heard the traditionally noisy compressor turning on and off for weeks. Oh well! More expense! 😦 To be fair, it was 40 years old, I just about remember the one before this one. It was one of those with a lock on the front that used to trap children inside discarded ones and suffocate them. I remember public safety adverts about them, when I was very very young.

It was a very good fridge, a Scandinova LF111D, which I had been repairing here and there, not a lot, but had kept it going: a new handle, fixing the light shroud, replacing broken glass shelves. So reluctantly, I started to look for a new fridge on google, and then thought, well let’s test it first. After all, I have a new digital multimeter, as well as the oscilloscope that I had very recently purchased. Plus, if I can reverse engineer a Z80 UART using ASICs, then surely I can repair a god damn ‘fridge..!

Video tutorials

Following an excellent series of tutorials by Bill Newberry, I set to work. First, checking the compressor.

After getting around to the back of the fridge, and ensuring that it was unplugged, I quickly located the compressor. However, how could I get to the three terminals that the chap in the video was testing, as there was a lump of plastic in the way.

Black plastic shroud
Black plastic shroud

I had to unscrew a retaining philips screw, to remove a black plastic shroud, that easily lifted off, revealing the relay (the white bakerlite assembly).

Compressor and Relay
Compressor and Relay

Then I wiggled the white relay, until it came off, revealing the three terminals. Success!

Top view of the compressor
Top view of the compressor

My terminals were oriented upside down with the triangle pointing down.

Rear view of the compressor
Rear view of the compressor

The two horizontal terminals gave a reading of 40Ω, higher than the 10Ω that the chap had, the others were 16Ω and 24Ω, higher than the 4Ω and 6Ω.

So maybe the readings weren’t the same, but the fridge, like I said was old, and at least they weren’t open circuit.

However, watching the first minute of this video:

The two lesser resistances add up to the larger horizontal resistance, which mine do, so all well and good.

Now to test the relay! Making sure that the fridge was still unplugged. I gingerly attached the DMM to the two terminals.

Testing the relay
Testing the relay

I plugged the fridge back in, and adjusted the thermostat to maximum. However, no reading showed up on the DMM. So, I can only assume that the thermostat is broken. You can see the thermostat plug point here in the top left of the photo.

Rear view of the fridge showing thermostat
Rear view of the fridge showing the thermostat plug point black cover

So, looking up Bill’s video for the thermostat test.

So how to get to the thermostat and short those wires out, eh? Well, looking at the top front fascia panel, there are three white grommets, or screw covers.

All three fascia screw holes
All three fascia screw holes

I prised those out easily enough.

The three screw covers
The three screw covers

Then, looking down the long holes, I couldn’t see what type of screws held the fascia on with. I shoved a Philips and then a flat bladed screw driver down there, to no avail.

Middle screw hole
Middle screw hole

I decided to have a google, and found this thread, [sic]how do i replace the thermostat on my scandinova lf111d fridge ?. The screws turned out to be star number 25. However, the best bit was that I could just get the fridge up and running immediately. Quoting the relevant point:

It appears that the Scandinova people have thought about thermostat failures. Unplug the compressor lead and put it back in to the central connection point.

What?!?! So, I can short the wires out of the thermostat just by plugging the compressor lead into the middle socket of the thermostat/power plug point? Wow, this fridge really is a blinder. So, ensuring that fridge was unplugged, I got the black cover off the thermostat/power plug points, which was a bit tricky, having to lever the left hand side down, as per the instructions.

Don’t cut off the tabs on the black box at the rear; they are hinges for the lid; just leaver it off/ down from the left hand side (when looking from the back); it will swing down easily, enabling safe replacement when the job is done.

Sure enough there were three sockets, only the left and right one were used.

Compressor using thermostat
Compressor using thermostat

I unplugged the compressor lead from the right most socket

The two empty compressor sockets
The two empty compressor sockets

and plugged it into the empty socket in the middle.

Compressor bypassing thermostat
Compressor bypassing thermostat

I excitedly unplugged the refrigerator back into the mains and Hey presto, the fridge restarted! Excellent.

OK, maybe the job isn’t quite finished, but at least it is working until I can get a new thermostat. The instructions for which are below (see Reproduction of the instructions).

However, having gone through this myself, I shall continue, as my experience differed from the instructions, somewhat.

Empty the fridge! Or at least the fridge door. Also, make sure the fridge is disconnected from the mains!

It is necessary to remove the door, else the Control Panel Cover will not come off. This is easy, just remove the two Star 25 screws, hold ing the top hinge, with the door closed. Lift off the top hinge, whilst supporting the door.

Top Hinge
Top Hinge

Lift off the door and move it away.

View from top with hinge removed
View from top with hinge removed

Remove the three screw covers, in the top  Control Panel Cover (we did this above, see photos). Unscrew fully, and remove the three star 25 screws holding the panel on.

All three fascia screw holes
All three fascia screw holes

Here are the removed screws

Three control panel cover screws
Three control panel cover screws

Remove the light shroud (carefully – it breaks easily), remove the light bulb, and prise off the thermostat control knob.

Control Panel Cover with fittings removed
Control Panel Cover with fittings removed

Gently, pull the Control Panel Cover off, to reveal the control panel itself

Control Panel
Control Panel

Now remove the thermostat retaining nut holding the thermostat control to the Control Panel.

Nut holding the thermostat to the control panel
Nut holding the thermostat to the control panel

Now gently pull the control panel off, BUT there is no need to remove it fully, as it requires unhooking lots of wires. You just need access to the thermostat itself, and the lugs coming off it. Do not pull the thermostat too hard as the probe might come out of the fridge.

Thermostat
Thermostat

Now, going into the thermostat, you should see a stiff probe wire, a couple of white wires, going to, and joining at, just one clip, the earth wire, a red wire and a brown wire. It is the red and brown that we are interested in.

Thermostat with the red and brown wires
Thermostat with the red and brown wires

Now, in Bill’s third video, the one testing the thermostat, he says to short out the two pins, with the wires still attached and the fridge’s compressor should start (if the fault is indeed with the thermostat). However, I am not sure if those wires carry mains, so I was hesitant to short them manually. However, handily, there is a secondary lug on the brown (top) clip, to which you can attach the red wire’s clip.

Brown clip with the extra secondary lug
Brown clip with the extra secondary lug

So, ensuring that the fridge is disconnected from the mains, pull the red clip off it’s lug and attach to the secondary lug of the brown wire’s clip.

Red clip attached to the secondary lug of the brown clip
Red clip attached to the secondary lug of the brown clip

Now, before completing the test, if you moved the plug to the compressor to the middle plug socket, in the thermostat/power plug points, at the back of the fridge, you will need to return it back to the right hand socket, coming from the thermostat. Having done that, if necessary, then plug the fridge back in to the mains supply. The fridge should now start, because we have, yet again, shorted the thermostat out of the equation. This now confirms that the thermostat, or the probe, is at fault. It is probably the thermostat itself though, so you will need to replace it.

Now, unplug the fridge from the mains, and disconnect the thermostat, and remove it. Detaching the probe could be difficult. Best to leave the probe in situ, so you don’t have to rethread it. Or follow Rob’s string threading tip from howtomendit.com.

Get some insulation tape/ sellotape and a reel of cord/ string. Tape 10 to 15 cm of cord/string to the OLD thermostat tubing whilst still in position BEFORE you pull it out. When you gently pull out the old tubing from the front the cord/ string will follow through all the pipes and bends. When fully out repeat in the opposite direction with the cord taped to the new tube end and the new tube will be threaded back through with ease!

Regardless, you will need to order a replacement. This one, Scandinova Fridge And Freezer Thermostat Scandinova KF4315 KF4340 KF4350, from partsmaster, is NOT the correct part! It is missing a fourth lug for the temperature gauge. as per the instructions from howtomendit.com, the one from espares.co.uk, Replacement, is the correct one. Also, they are must cheaper than partsmaster. However, they appear to be out of stock. Turning to eBay, the Replacement for Selected Scandinova Hitachi Proline Vestfrost Fridge Thermostat is the cheapest, at £24.99 + £2.99.

While you wait for the new replacement thermostat to arrive by post, you will need to move the compressor plug back into the middle socket on the thermostat/power plug points, ensuring that the fridge is disconnected from the mains. You may find that the fridge gets too cold, and the compressor get very hot, so best to connect the fridge to the mains via a timer socket.

Mains Timer Switch
Mains Timer Switch

Just to make a complete audit, these are all of the bits you should have left over (store them safely). Here are the 3 control panel cover screws, 3 screw covers, 2 hinge screws, along with the thermostat knob, thermostat retaining nut and the bulb and bulb shroud.

All of the removed fittings
All of the removed fittings

Reproduction of the instructions

I will quote the instructions here, in the case of link death (which happens so often!)

First Rob’s addendum to Neil’s instructions:

STOP; READ THIS FIRST!
Excellent instructions form Neilm but………..
I have just replaced the thermostat; it is easy to do.
MAKE SURE POWER IS OFF.
1) Don’t cut off the tabs on the black box at the rear; they are hinges for the lid; just leaver it off/ down from the left hand side (when looking from the back); it will swing down easily, enabling safe replacement when the job is done.
2) You don’t need to remove the door to take off the fascia at the top of the fridge. It saves a lot of time and agro. Just make sure the door swings open as fully as possible.
3) Get some insulation tape/ sellotape and a reel of cord/ string. Tape 10 to 15 cm of cord/string to the OLD thermostat tubing whilst still in position BEFORE you pull it out. When you gently pull out the old tubing from the front the cord/ string will follow through all the pipes and bends. When fully out repeat in the opposite direction with the cord taped to the new tube end and the new tube will be threaded back through with ease!
Thanks for the rest of the instructions; switching the wiring at the back was a great diagnostic help confirming that a faulty thermostat was the problem.
Fully functional repair for £23.50

Now Neil’s instructions

Okay,

Tools for the job, wire cutters, medium size flat screwdriver, a number 25 star drive (an allen key will do) at least 60 mm long. approx 1/2″ spanner or pliers to undo a nut, a cross head screwdriver, a pointed knife or fine screwdriver to remove the control panel bolt covers.

I have the same problem and have had a look.

The spare part can be bought from

http://www.espares.co.uk/parts/fridges-and-freezers/scandinova/if111d/p/1084/1198/0/546871

When you find the fridge has warmed up, the first thing to do is get it working all be it full on without the thermostat.

Get the fridge away from the wall, TURN OFF THE POWER, clean all the fluff and gunge that has accumulated under the fridge and get down on the floor to have a look behind. There is a a black plastic box on the left hand side (looking from the back) with the power cable going in.

The cover needs to come off, this is not the approved method but, there are two ‘wings’ sticking out from the top side of the box, cut them off and lever the cover off. The are two square holes on the opposite side of the box which have ‘open’ next to them but I didn’t see that until the cover was in my hand.

There are two power leads under the cover, one from the mains, the other going to the large black cylinder in the base of the fridge, the compressor pump, and there are three lead connection points the middle one being empty. It appears that the Scandinova people have thought about thermostat failures. Unplug the compressor lead and put it back in to the central connection point. Then turn on the power and the fridge should start to work. Ours now has -10 degrees on the temperature gauge too cold but better than no fridge. Put the fridge back to the wall and continue to use for the time being.

Order the thermostat.

Re-placing the thermostat.

TURN OFF THE POWER. Empty the fridge.
Remove the door using the star key on the two bolts at the top of the hinge. Do this with the door shut whilst the hinge is undone, then gently lift the door off over the light cover in the top of the fridge.

The thermoststat is behind the temperature control in the control panel at the top of the fridge. The coin operated 0 – 7 control on the right.

Remove the light cover by turning it leftwards and gently pulling it away.

Using a fine screwdriver or knife take the three covers out of the control panel. Behind are three bolts with the same size head as the door bolts. Remove them.

Remove the temperature control knob, or let it will come off as you take off the control panel cover. Gently ease the control panel off. It will probably be a bit caught on the thermostat probe tube.

In the back of the fridge is the cooling panel. Slacken off the two cross head screws which are clamping the thermostat probe to the back of the cooling plate.

Use the flat head screwdriver to push in the four spring loaded catches holding the cooling plate. Push in the sprung nob and whilst doing that pull the cooling plate of the mounting post (firmly but carefully). When you have undone the last one the plate can be swung aside to reveal the thermostat tube, unclip the tube from the back of the cooling plate and at the control panel withdraw the tube from where it goes into the top of the fridge. As you pull it out it will get stuck on any bends in the pipe behind the cooling plate so straighten it as you go. You can now cut off the tube if it is getting in the way.

I am still at the waiting for the thermostat stage. So the rest is supposition!

Take careful note of which lead goes where on the thermostat and unplug all the cables on it. Undo the nut holding the thermostat in place and now you are ready to put the new thermostat in place.

First put the compressor pump cable back onto its original connection.

Simply do in reverse what you did to take it all apart, mounting the new thermostat onto the control panel, reconnecting the wires to the thermostat as they were before, coiling the long thermostat tube behind the cooling plate and ensure the end is clamped by the holding bracket as it was when you took it out.

It is a good idea to do a quick test at this point to see that the fridge now comes on as it should. And try turning the temperature control to zero to check that the pump turns off. TURN OFF THE POWER again whilst you continue to re-assemble the fridge.

Re-assmble the front control panel and bolt back in place, put the light shade back. Put the door back by gently placing it on to the bottom hinge spike and carefully closing it around the lampshade. Then remount the top hinge.

Put the cover back on to the cable connections at the back and you should now have a properly working fridge.

That’s all folks!

folks

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