Hints for Improving Fridge efficiency & prevent problems

Submitted: Monday, May 15, 2006 at 03:18
ThreadID: 122672 Views:4528 Replies:6 FollowUps:2
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FAN FORCED AIR CIRCULATION
We have a thermometer temperature probe in our fridge at top shelf level and this has been displaying 7 to 9ºC and when the door has been opened took a long time to cool down again. The thermostat has been set on 2.5 to 3.
The Waeco man in Alice Springs suggested to me that a fan inside the fridge would make the fridge run more efficiently. I took his advice and purchased a computer fan from Dick Smith that has a square plastic frame around it with holes in each corner. Using pieces of wire cut from a coat hanger bent with hooks on them, the fan was mounted under the centre of the top shelf at the rear so that it blows air downwards over the cold rear plate. (just have to leave a gap under fan to allow air movement.) After installing the fan to circulate the air, we have found that the temperature probe now shows 1 to 4ºC with the thermostat set on “1” and it is an even temperature through the fridge instead of being cold at the back and warmer at the front.
The fan draws 300mAmps/hour or 7.2 Amps for a 24 hour period, and I used 12 volt power from a lighting circuit through a switch to power it. The wires need to have easily removable connectors so that if the fridge has to be removed they can be disconnected. I ran the wires in under the door seal on the upper side of door opening to reduce any losses due to small gap in seal.
The 7.2 amp draw per day is probably replaced by lower compressor use due to lower thermostat setting and more efficiency of cooling.
I would recommend this to all owners.

THERMOSTAT
The thermostat that is fitted to a 190 litre Waeco fridge can be replaced with a generic cyclic thermostat if the Waeco one is not available. If you find that your fridge is not working properly or cutting out momentarily, then it may be the thermostat. Apparently the thermostats have a habit of developing carbon on the contacts and this poor contact causes the fridge to stop and start. To test if it thermostat problem, if you go to the rear of fridge, and disconnect the 2 lower wires from “C” & “T” terminals (bottom and 3rd from bottom) then connect a wire between these 2 terminals by slide on or alligator clips, the fridge should now run continuously. If it does then it would indicate a faulty thermostat.

Replacing the thermostat yourself is easy. Unscrew the cover off the round plate over probe on rear of fridge and then the 2 screws holding the light and temp control unit in place. Slide the holder forward and the rear clips will release. Pull the temp dial off and undo not holding thermostat in place. Remove 3 wires and put them in same place on new thermostat and re-install everything making sure that the end of probe is touching the back plate of fridge. Thermostat will cost about $50.

RESISTORS
The WAECO fridges are made in Europe for their cooler temperatures and for Australia’s warmer climates it is necessary to insert a resistor into the Thermostat circuit that makes the compressor work a bit harder. Without the resistor the fridge draws about 3 Amps but will draw 5 to 6 Amps with a 1500 Ohm Resistor. The resistor is located on the lower terminal at the Control Panel and is a small cylinder with 1mm wires coming out of it that connect to spade terminals, and is then covered in shrink wrap. I have had 3 of these resistors break the wire as it goes into the resistor and when that occurs, the fridge either runs intermittently or not at all. I think if a piece of plastic cable tie was placed along side the resistor and wire and then another shrink wrap put over the top, it would prevent the wire breaking on rough roads.

DOOR HINGE
The 2 doors of the Fridge rely on a pin that is pressed through the hinge bracket. This pin has small groves in it but ours came loose and dropped down allowing the freezer door to fall off. A small dab of weld on the pin bracket joint would prevent this happening. The newer fridges have an American type hexagonal screw head and you require a special driver available in hardware or Cheap Auto stores. It pays to carry this tool with you.

DOOR SUPPORT
The bottom door has a fair amount of force on the hinge if loaded up, so an angle bracket screwed into the holes provided for changing the side the door is hinged from is a useful way of supporting the door. Our angle bracket has holes drilled in the top to take the 2 plastic tabs covering the holes in the fridge, and the door rides up on these tabs when closed and provide support.

DOOR SHELVES
We have had a number of door shelves break, and some was because there was no support on the clip that holds it in place. I put a bit of fibre glass BOG against the plastic clip and this helped strengthen it a lot. I know it doesn’t look good but I have also found that grey duct tape running across the front of shelf and onto the door also helps support the shelf. I know Steve’s advice is to remove heavy items from shelf when on rough roads, but this is not always practical.

DOOR LOCKS
My fridge came with white plastic tabs that clipped over a catch on the door. These are supplied by WAECO and if there is any movement of the door on rough roads break easily. Bti now use a soft flexible plastic catch that is actually a child proof cupboard lock. They are a little harder to use that what WAECO supply but are much stronger. They are available in most hardware stores, and are secured by screws of pop rivets into the side of the cabinet.
IF DRILLING INTO CABINET be aware that around the front of the freezer door there is a heater tube to prevent the door rubber sticking to the cabinet when it is frozen inside. MAKE SURE you put your holes about 50mm back from the front to prevent drilling into this pipe. Bti may have better details of how thick this NO DRILL section is.

DOOR SEALS
If your rubber door seal is not seating properly then it can probably be fixed by using the heat from a hair dryer to warm up the rubber and then the magnetic strip inside the seal will be able to make contact with the fridge and mould itself to the new shape.

LIGHT VOLTAGE CONTROL UNIT
At the rear of the fridge screwed to the base plate is a piece of Aluminum channel about 40mm long by 10mm square. Inside this channel is a black plastic block with thin wires going into it. Because the wires can flex and the block is secure we have had the wires break twice and this stops the fridge light from working. The unit is there so that if a 240 volt transformer or 24 volt supply is attached, the voltage to the light will be reduced to 12 volts.
A simple fix for this problem is to fill the channel with silicon and prevent the wire flexing continuously as it enters the plastic block.

WAECO “MPS 50” 240 volt Transformer
We have found that if the battery voltage is around 12 to 12.2 volts that often the fridge will not be able to start because the current draw to start the compressor causes a momentary voltage drop of about 1.5 volts, and this is enough to trigger the low voltage battery protection cut off. If this occurs I turn the Inverter on and switch transformer on and then the fridge will happily start on the same battery voltage because it is now boosted up to 27 volts via the transformer.

LOW VOLTAGE AT FRIDGE COMPRESSOR
Normally there is very little voltage drop between the battery and fridge compressor, ours is 0.1 to 0.2 volts, because Bti use a suitably sized cable to prevent this drop. Recently we had a massive 1.5 volt drop and on investigation found that it was a faulty MPS 50 Transformer. When I purchased a new transformer I was informed that they have had a lot of faulty ones returned. If the fridge is trying to start and cutting out all the time it will probably be due to low voltage, so it is worth checking the voltage at the compressor even if the Solar Regulator says you have high 12 or 13 volts in batteries.

On advice from Bob (TURIST) Pollock I blocked off the outside vents to our fridge and installed the fridge so that there was an air gap under it by leaving the small legs attached that Bti usually remove on installation. I then put an air vent above the rear top of fridge and this allows air to circulate as per Installation instruction in the Waeco booklet. I believe the fridge operate more efficiently without getting dust on the condenser and not having hot outside air going on the condenser.
If you do ask Bti to duct the fridge internally make sure you still have an inspection opening at the rear so that you can measure voltage and make minor repairs without having to remove the fridge.

These are all faults we have had over the past 5 years covering 120,000 km and a lot of it being off bitumen.

Hope this helps others that may have problems with their 190 litre fridge.

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Reply By: Silver Fox - Monday, May 15, 2006 at 07:36

Monday, May 15, 2006 at 07:36
Thank you for the valuable hints. A while ago I wanted more cooler circulation and added two 'Game Dude' computer fans on the inside of the upper vent to move more air over the coils etc. (in my photos) I then made some holes into a cupboard adjacent to the fridge for inside air when it is cooler than outside air. I replaced the lower vent with a sheet of plastic and inserted a "butterfly" vent. Now I can open it when stationery and the inside air is hotter than the outside air. I am hoping it is dust proof. when closed. As you can see I also added a couple of 12v power outlets (for outside lights mainly). Not tested yet but it looks like it should work. However I will check out the other ideas you have written which I haven't known about. I now have a generator fitted so may well be able to increase the batteries voltage should that be a fridge problem. One idea I used which I don't think you mentioned was the use of self tapers instead of the fasteners on the louvered vent. cheers.
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Reply By: Kiwi1 - Monday, May 15, 2006 at 07:39

Monday, May 15, 2006 at 07:39
Jeez, Brian, maybe warm beer might be an easier option (wink). You could store heaps of it in the space that that troublesome old fridge is taking up.......

Michael
AnswerID: 568548

Reply By: Bushtracker - Monday, May 15, 2006 at 18:32

Monday, May 15, 2006 at 18:32
The Lone Ranger is Back!

On the fridge, it is the best practical, but unfortunately not everything is as well built as a Bushtracker....

I would say however, due to the constant hounding and feedback, they are slowly improving, and the latests ones are getting better....

Regards
AnswerID: 568549

Reply By: Boystoy - Thursday, May 18, 2006 at 08:06

Thursday, May 18, 2006 at 08:06
Hi Brian & Margaret,

I like your informative posting. Question, what is the physical size of the computer fan that you used.

Neil
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Follow Up By: Noosa Fox - Friday, May 19, 2006 at 01:58

Friday, May 19, 2006 at 01:58
The plastic square around it is about 100mm
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Reply By: Freewheelers - Friday, May 19, 2006 at 02:23

Friday, May 19, 2006 at 02:23
hi all
brian very informative post
we have a 2005 waeco 190 litre fridge
~just had a look the door shelf brackets are reasonably flimsy (slide down plastic)
~seems you tend to get them set into one position & leave them there
~a small self tapper through the shelf into the door support plastic rib from the shelf side would add a lot of strength for little effort
~or better still a small bolt right through the shelf & rib could look neat & any future adjustments could be cover with a small plastic plug
~does any body know if the is anything within this vertical rib
~ ???heavy loads may pull the bolt through the rib if you do a lot of rough roads any comments thanks
Stephen & Deborah

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Reply By: BTMTS - Wednesday, May 24, 2006 at 05:38

Wednesday, May 24, 2006 at 05:38
All
Thank you very informative.

Perhaps a dumb question but...
I note that there have been a number of suggestions in the forum for moving the fridge cooling coils from venting externally to venting internally into the van.
Seems sensible for a range of reasons but I would seek Steve's views, noting his comments in this thread that improvements to the fridge are desired, but what about the "standard" ifridge nstallation?
Clearly the fridge is the main battery drain and as such warrants close attention.
Thoughts?
pce
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Follow Up By: Bushtracker - Wednesday, May 24, 2006 at 18:40

Wednesday, May 24, 2006 at 18:40
Peter, Look up Tip # 99 on the Owners Forum as to the reasons and research...

If you cannot become a Member, if you do not have a Bushtracker or one on Order, you can email me at Bushtracker with your particulars...

Look: Others copy our style and research all the time, not in bones but in the look of the Bushtracker... That only fools people that do not know what they are looking at, or the sheep that do not bother to go to the respective Factories and just buy off the showroom or show... But there is no sense in giving away our R&D on the Public Forum... Make em work for it a little ... Ha!

Lone Ranger
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