Isotherm fridge thermostat probs

[GHA]

Pretty sure it's the thermostat, seems to run OK with a jumper lead across terminals C & T on the 101n022controller.

So is it common for a thermostat to go?

Should I just bite the bullet and order a new one or are they fixable?

Fan's gone as well.

 

[charles_reed]

Pretty sure it's the thermostat, seems to run OK with a jumper lead across terminals C & T on the 101n022controller.

So is it common for a thermostat to go?

Should I just bite the bullet and order a new one or are they fixable?

Fan's gone as well.

Never had mine go (yet) but have had problems with ice around it causing the unit to cut out.

Fans go quite frequently, just replace with a computer cooling fan - I'm using a 140mm one which moves considerably more air than the standard one.
Buying from the manufacturer is likely to be expensive - they're all proprietary items.

 

[GHA]

Never had mine go (yet) but have had problems with ice around it causing the unit to cut out.

Fans go quite frequently, just replace with a computer cooling fan - I'm using a 140mm one which moves considerably more air than the standard one.
Buying from the manufacturer is likely to be expensive - they're all proprietary items.

Cheers, the capillary pipe snapped when I was in there trying to have a look so its definitely bust now!
Tempting to make one with a little arduino board and some waterproof temp sensors. Wouldn't cost much & there's a few sensors on board already. .

 

[dnickj]

hi

here is a good way forward

http://www.ebay.co.uk/itm/New-220V-...ial_Automation_Control_ET&hash=item51b7426358

sorry this link is for 230v but the unit is available foe 12v but at twice the price

 

[parbuckle]

http://www.rparts.com/documents/CR_011-1020_Manual_v2dw.pdf

This may be useful for diy ideas dont bother to look for the price .

 

[GHA]

Thanks all, I've got an arduino uno talking to a temp sensor within half a degree of a digital thermometer so at least if I should be able to get something rigged up so i dont have to keep switching the fridge on and off.

What temp range though?
Was thing switch on at 5deg the off at 3deg
Sound about right?


ps
sensor is one of these
http://www.maximintegrated.com/datasheet/index.mvp/id/2812

 

[GHA]

has anyone tried a little fan inside the fridge blowing across the evaporator plate?
Might give it a go.

So now we're looking at an arduino, temp sensors top and bottom of the fridge and one on the compressor with the arduino varispeeding fans in the fridge and maybe a couple on the compressor since they're so cheap. Just a bit of wiring , some easy programming and probably cost less than a new thermostat.

 

[oldvarnish]

has anyone tried a little fan inside the fridge blowing across the evaporator plate?

Yes, I did that in the tropics, as recommended by someone on here. It's difficult to be certain, but the fridge seemed to run for less time than I expected.

 

[GrahamM376]

According to the fridge repairer I bought one from for our Isotherm, they're standard domestic thermostats, the main differences being the lengths of the capillary pipe. Just being a switch, operating voltage not a worry.

 

[nimbusgb]

A COTS electronic unit as per post #4 is far prettier, boxed and housed with a nice display and probably costs less than an arduino setup anyway.

I used a Dixel unit.

 

[typhoonNige]

hi

here is a good way forward

http://www.ebay.co.uk/itm/New-220V-...ial_Automation_Control_ET&hash=item51b7426358

sorry this link is for 230v but the unit is available foe 12v but at twice the price

We went down this route 18 months ago. It works a treat! £12 free delivery IIRC

 

[GHA]

A COTS electronic unit as per post #4 is far prettier, boxed and housed with a nice display and probably costs less than an arduino setup anyway.

I used a Dixel unit.

Arduino is less than a tenner, is working as we speak and soon will varispeed fans, log current draw/voltage and temp over time (with some other bits i have already) , and generally is so much more fun

Will probably add couple of quid for a display and a few pennies for some transistors to control the fans inside and at the compressor.
Maybe a little half hour sleep button for receiving weatherfaxes, so many times I've forgot to turn it on again...

So for the boffins - controlling brushless fans using PWM/transistors - any little points of interest lie along that road?

 

[nigelmercier]

Arduino is less than a tenner, is working as we speak and soon will varispeed fans, log current draw/voltage and temp over time (with some other bits i have already) , and generally is so much more fun

One thing I've always thought would be a good idea, reducing the fan speed a little at night, or perhaps when it's dark (or indeed otherwise quiet).

 

[GHA]

One thing I've always thought would be a good idea, reducing the fan speed a little at night, or perhaps when it's dark (or indeed otherwise quiet).

I've always wondered if so much of the advice actually does anything or not, like fill the fridge up! Or lots of fans.

Might find out now..

 

[SimonJ]

Fridge thermostat

Pretty sure it's the thermostat, seems to run OK with a jumper lead across terminals C & T on the 101n022controller.

So is it common for a thermostat to go?

Should I just bite the bullet and order a new one or are they fixable?

Fan's gone as well.

I did the same check as you & found the thermostat had failed. But it was in continual use for about 6 years in and out of the tropics. Do problem am be common!

 

[GHA]

14 hours of fridge
Think the breadboard lead to the fridge from the transistor got pulled out for a while before 04:00.

 

[nigelmercier]

14 hours of fridge

I want one

I don't understand the graph though, why is it taking longer to heat up during the day?

 

[GHA]

I want one

I don't understand the graph though, why is it taking longer to heat up during the day?

The time was done just using a variable as there's no real time clock attached just now, 0:00:00 is actually round about 10am iirc.


edit: And full marks , well spotted.

 

[GHA]

And with the evaporator plate temp as well....

So, what's the most efficient way to run a fridge....?

I'm thinking pump on about 4 deg and off at 5, is that OK to keep food in?

 

[GHA]

As this might end up permanent and those little sensor are so cheap, why not bang a few more in, with the choice of triggering an alarm as well.

First things come to mind are exhaust water trap, stuffing box and alternator - think of any more?