Help With Wiring Fridge

[Kramer]

OK I bought a nice 510 litre fisher & paykel (sp) for $25 Bargain :beerbang: its frost free and reversible doors!

But its thermostat is missing, I can buy a new one for $100, I have also ordered a couple of other thermostats for fermenting etc I might want to hook one of those up! I have included the wiring diagram one blank if anyone wants to mark it to show me where to connect up the other thermostat, and the other one where I have marked some weird things!

The blank one

Ok on this one there is 2 thermostats why? As far as I know there should only be one I think that the one in the freezer is for the automatic defrost? also if I connect the other thermostat should I just bypass the rest of the fridge and just connect it to the compressor? blue dots - this may be the easiest just extend both fan wires and hook them up at the compressor as well so they switch on when the compressor does, or put it where the original thermostat was?

Any help would be appreciated? Also I have no worries about wiring 240V as I used to be an apprentice electrician only got 18 months in but that is another story - and no I didn't fry anyone!

Sorry for the long post.

 

[timmy]

You Could add a digital temp controller for around the same price as an OEM one.

Looking at the diagram the cooling thermostat is just a single pole single throw so a simple contact is all that's needed.

The freezer thermostat is just a defrost thermostat as it's set points are pre set.

Because the defrost timer has its own supply something like a Dixell XR10C for $100 at kirby's would be the best option.

Edit: the thermostat in the second compartment is probably just for directing air between compartments.

 

[mistylane]

Ignore the defrost thermosat - it will only operate under 9 degrees anyway (open circuit). It seems at 66 degrees (bloody hot) it will stop the defrost element from working.

The thermostat for the fridge - of course the original one is probably useless for brewing - the upper temp. range could be 10 degrees and that's it (maybe good for largers??)

It really depends what kind of thermostat you have - mosy people I know get a kit from jaycar and turn the mains off and on with a probe in the fridge that ranges from 0 to 30 degrees! In winter this operates a heating element (or light globe) when brewing.

 

[timmy]

Ignore the defrost thermosat - it will only operate under 9 degrees anyway (open circuit). It seems at 66 degrees (bloody hot) it will stop the defrost element from working.

The defrost thermostat runs off coil temp not compartment temp.

 

[Kramer]

Well thanks for that it has cleared up some issues, I have bought 2 of these and will put another relay in it to handle a bigger amperage as they are only rated to 2A. Even though the fridge says it only pulls 1.7A I think the startup current will be quite a bit higher!

Cheers Kramer.

 

[OCC]

you don't really have to put the relay in if you want to keep the circuit simple i,e where will you mount the relay .. the start current will only be 3 amps or so for no longer than 1 second and the compressor will not be coming on that often , the thermo contacts will be able to handle this as they usally under rate them to be on the safe side..
so if ya want to keep it simple just drive it though the thermo...
occ

 

[timmy]

Remember this is inductive load. even if it is only 3 or 4 amps on startup it will effectively be putting more load on the relay contacts than a resistive load.

Personally on a domestic fridge, especially a 510l jobbie, i would use nothing less than 20A relay contacts. sounds a lot but remember they can only take 8A inductive.

 

[Kramer]

Thanks guys but I am with Timmy here an inductive load is a lot more than a resistive load, thanks again I am now off to Ideal to grab some relays.

Cheers Kramer.

 

[Sparky]

Remember this is inductive load. even if it is only 3 or 4 amps on startup it will effectively be putting more load on the relay contacts than a resistive load.

Timmy's point is important

Starting current on most electric motors is 6-7 times full load current & remember it's an inductive load you are switching. (Listen to the crackle the light switch makes when you turn off a fluorescent light. Domestic switches are not usually inductive rated)

Check that the relay is inductive rated. Many only give a resistive (household incandescent lights/ one bar heater type) load rating which is very different to the sparking type switching that occurs when a compressor starts.

 

[Kramer]

Ok its all wired up but not finished off, had to ut a hole through the freezer section to the fridge to make a complete fridge as the fridge element died! My grinder is in Bundy as the rest of my tools, so I used a chisel, really rough but I am known as the king of bodge by all my mates so why dissapoint them! Luckily I used a chisel cause if I hit it with the grinder I would have chopped a heap of pipes!

Thanks for everyones help, but it would have been cheaper to buy a dixel or something similar in the end, Thermostat - $23.00, Relay - $25.00, Din rail mount $9.00, then the cover $5.00 all up $62.00 plus a bit of postage on the thermostat.

Here are some pics don't laugh too hard!