Fan cooled Trailblazer

Submitted: Saturday, Feb 26, 2005 at 22:28
ThreadID: 20811 Views:2574 Replies:7 FollowUps:16
This Thread has been Archived
Have recently mounted a 12V fan blowing onto the compresser, (inside the Trailblazer motor compartment) making it more effeciently to run (so I have heard!!?), problem is, I can not find the right wiring sequence to hook the fan into so it will only run when the compressor does, when working on battery. Could anyone out there pleeeaaase shed some light on my frustration!!!

milo...

PS - I am sure someone has done this already!
Back Expand Un-Read 0 Moderator

Reply By: Crackles - Saturday, Feb 26, 2005 at 23:18

Saturday, Feb 26, 2005 at 23:18
I don't believe just blowing fresh air over the motor will make much difference to the efficiency but rather needs to blow over the condensor instead to get rid of the heat. (Not sure where the condensor is mounted on a Trailblazer) To run the fan I expect you will be looking for the wire between the thermostat & the motor. Check that the compressor is actually running on 12 Volts too as I found my old Engel was actually running on 32 volts AC when putting my fan on.
Cheers Craig.............
AnswerID: 100321

Follow Up By: ozi explorer - Saturday, Feb 26, 2005 at 23:49

Saturday, Feb 26, 2005 at 23:49
Am still not sure how affective it is as I havent had it running succesfully yet that is, cutting in and out with the compressor, I tried hooking it into wires between thermo and motor - starts ok with compressor but stops later when comp. continues as is back feeding through the wiring keeping the comp. running.....make sense?? - Had trouble writing it to..

milo...
0
FollowupID: 358498

Reply By: ianmc - Saturday, Feb 26, 2005 at 23:23

Saturday, Feb 26, 2005 at 23:23
Used to have a trailblazer. Exc.frig.
Think the frig casing which is alloy is the condenser & they instruct U to leave air space around it for that reason.
Maybe the fan will use more energy than it saves if it just blows over the motor,probably wont cool the refrigerant much at all.
AnswerID: 100323

Follow Up By: ozi explorer - Saturday, Feb 26, 2005 at 23:53

Saturday, Feb 26, 2005 at 23:53
I have heard the minimal draw of fan allows the compressor to run cooler thus less often, thus less draw on power. Hopefully when ever I get it running!

milo...
0
FollowupID: 358500

Reply By: Member - Stephen (WA) - Sunday, Feb 27, 2005 at 00:27

Sunday, Feb 27, 2005 at 00:27
Yeah - I did this to my 40lt Trailblaza.

I got a kit from the 12 Volt shop here in Perth (approx $50)

Pretty simple install - unplug the existing tiny fan, mount the new bigger fan with cable ties and plug it in. The fan cuts in and out with the compressor.

The bigger fan certainly moves a lot more air around the compressor than the existing fan - I have it mounted so that it sucks in fresh air from the top and blow it over the compressor and blows it out the bottom holes. Thair is quite a breeze coming out of the holes now whereas there was no discernable air movement before. However I don't know that this makes all that much difference to the performance of the 'fridge - although I haven't run any sort of comparisons.

In hindsight I'd probably not have bothered and should've spent my $50 on something else.

Cheers
Stephen J.
VKS737 - Mobile 2735

Lifetime Member
My Profile  My Position  Send Message

AnswerID: 100331

Follow Up By: Member - Stephen (WA) - Sunday, Feb 27, 2005 at 00:48

Sunday, Feb 27, 2005 at 00:48
OK - I just went and took my 'fridge to bits.

Down next to the compressor is a controller/terminal box sort of thingy.
The terminals (from to to bottom) are: -,+,+,F,D,C,P,T.
The fan is connected to terminal 3 (the second "+" terminal) and the F terminal.
In my case there is nothing connected to the C and T terminals.

Hope this helps.

Cheers
Stephen J.
VKS737 - Mobile 2735

Lifetime Member
My Profile  My Position  Send Message

0
FollowupID: 358504

Follow Up By: Wok - Sunday, Feb 27, 2005 at 08:21

Sunday, Feb 27, 2005 at 08:21
Stephen j,

Curious you have no connection to C & T, that is where my thermostat is hooked to. Which controller model/Danfoss do you have?

Just curious
............................................................

Stephen[WA]

I fitted a blower to 'save' the compressor....don't think it does much for 'cooling' the contents of the fridge!

cheers all
0
FollowupID: 358518

Reply By: joc45 - Sunday, Feb 27, 2005 at 01:52

Sunday, Feb 27, 2005 at 01:52
As I recall, the Trailblazer uses a Danfoss compressor. The electronic control unit for the compressor has a pair of connectors for running an external fan. On my 10yo fridge (Autofridge) which uses the same brand compressor, the connections are clearly marked with a fan symbol on the body of the control unit. The output is the same as the battery voltage, and comes on when the compressor runs. As stated above, you would be best to direct the air onto the condensor to remove the heat, rather than on the motor.
Gerry
AnswerID: 100333

Reply By: Wok - Sunday, Feb 27, 2005 at 08:14

Sunday, Feb 27, 2005 at 08:14
I fitted a Jaycar blower to the lower right corner of the removable plate. It blows air over the compressor. On my controller there is a pin for a fan[1 amp max]. The pin is indicated on the controller. The fan + goes to this pin & the - to the battery input -.

Effectiveness?..........don't know..........hoping it will lengthen the compressor life!
AnswerID: 100342

Reply By: Member - Jimbo (VIC) - Sunday, Feb 27, 2005 at 10:32

Sunday, Feb 27, 2005 at 10:32
Now this may seem a bit dopey, but how can something that _Affordable_Storage_Drawers.aspx power reduce your power consumption? Assuming the fan _Affordable_Storage_Drawers.aspx about 12 watts/1 amp (or whatever) it is increasing your power draw by that amount when running. It would therefore need to reduce the running time of the fridge by a greater amount to be of any use.

Given that you don't get something for nothing, I fail to see how this can work. To me it defies the laws of physics.

Any thoughts?

Jim.
AnswerID: 100348

Follow Up By: Nudenut - Sunday, Feb 27, 2005 at 12:06

Sunday, Feb 27, 2005 at 12:06
yep, your right Jimbo.

But one can make the fridge more efficient by blowing air across an otherwise nomally convection draught condenser....this must also done be correctlly if the condenser is multi-pass type.

As far as I am aware the trailblaza uses the external skin of the fridge as the condenser...the condenser piping is taped to the internal skin during manufacture (as is the evaporator piping) and the foam insulation is pored in to the cavity...so do not drill holes into the outer or inner skins...you could put a hole in the pipe...and that means throw it away and buy a new one.....

IMO fitting a fan inside the compressor campartment isnt going to do a lot of good....
0
FollowupID: 358528

Follow Up By: Crackles - Sunday, Feb 27, 2005 at 12:31

Sunday, Feb 27, 2005 at 12:31
The fan blowing on the compressor should increase the motor life by stopping it from overheating. I believe Engel had that problem for a while after they changed to the current refrigerant gas. Blowing air over the condensor allows for a faster transfer of heat & shorter running time. Fridges in cars & campers particually those fitted in enclosed boxing systems need a fan to remove the heat build up where a fridge in the open air would get little advantage.
Cheers Craig......
0
FollowupID: 358529

Follow Up By: Nudenut - Sunday, Feb 27, 2005 at 16:47

Sunday, Feb 27, 2005 at 16:47
Crackles...both fridges have totally different compressor types....

"Fridges in cars & campers particually those fitted in enclosed boxing systems need a fan to remove the heat build up where a fridge in the open air would get little advantage."....the danfoss compressor is designed to operate in enclosed boxes. as most domestic fridges are..
the heat losses from the motor are tranfered to the refrigerant and disipated via the condenser.....the only type of compressor that will benefit from air being blown over it is one that requires oil cooling...and the Danfoss does not

"Blowing air over the condensor allows ............................shorter running time"...this is only be true if the condenser is inefficient or has inadequate rejection capacity at any selected temperature that one wants to compare it too... and applies to both convection and forced (fan) draft condensers...it would then allow for shorter running times as the condenser pressure and would give rise to the system having minamal or zero flash gas entering the refrigerant control device...apologies if to technical
0
FollowupID: 358546

Follow Up By: Member - Jimbo (VIC) - Sunday, Feb 27, 2005 at 18:52

Sunday, Feb 27, 2005 at 18:52
Makes sense to me Nudie.

Cheers,

Jim
0
FollowupID: 358551

Follow Up By: Crackles - Sunday, Feb 27, 2005 at 21:51

Sunday, Feb 27, 2005 at 21:51
My point with the fridge being stored in an enclosed boxing system was that it will always be more efficient if the heat can get away from the condensor & a fan will certainly help. I understand the compressor is designed to opperate in a box but when all the vents are enclosed in another box or gear packed around it then a fan must assist in some way to keep it running at the design temp.
Nudie, what are the 2 totally different compressor types you mention?
Thanks Craig.........
0
FollowupID: 358573

Follow Up By: Des Lexic - Sunday, Feb 27, 2005 at 22:50

Sunday, Feb 27, 2005 at 22:50
If you wanted to reduce the heat load from around the fridge carcase, wouldn't you mount a fan or two externally of the carcase and blow the hot air away from the outside skin and help dispose of the heat that way? I have my fridge inside a mesh enclosure so that there is plenty of free air surrounding the fridge. The temperature still builds up to near 50 degrees celsius on a hot day but the inside contents are still beautifully cold.
0
FollowupID: 358584

Follow Up By: Nudenut - Monday, Feb 28, 2005 at 08:11

Monday, Feb 28, 2005 at 08:11
Crackles, the compressor in the danfoss is a reciprocating type while the fridge in the Engel is a swing type...basicly operates similar to a soleniod while the plunger acts as the piston...

The idea of fitting a fan inside the with the compressor sounds good to the uninitiated, but in reality it would be a waste of time...the vents in the compressor compartment is for the heat generated from the 240v - 12vdc transformer to escape...if it has one.

Des, yes thats what one would do but it would be a headache to mount and keep safe etc etc
I use a flat piece of thin ply same size as the fridge with 2 vertical 20mm square slats same height as fridge fastened to one side at each end of the ply and stick this next to the fridge... it gives a thin air vent space allowing the foul er hot air to vent
0
FollowupID: 358603

Follow Up By: Crackles - Monday, Feb 28, 2005 at 20:54

Monday, Feb 28, 2005 at 20:54
"The idea of fitting a fan inside the with the compressor sounds good to the uninitiated, but in reality it would be a waste of time...the vents in the compressor compartment is for the heat generated from the 240v - 12vdc transformer to escape...if it has one."

Sorry Nudie but your theory on the compressor fan seems to go against arguably one of the more efficient fridges that being the Autofridge. The condensors are the Aluminium sides, they have no 240 Volt transformer, yet they have a fan blowing directly on the motor????
0
FollowupID: 358729

Follow Up By: ozi explorer - Monday, Feb 28, 2005 at 22:55

Monday, Feb 28, 2005 at 22:55
I would also have to agree with crackles on this one, but as to my own 'initiated' opinion on fitting this fan to my fridge is, 'If something is working and is hot, trying to keep it cool can only do better for it.'
Time will tell, as testing is underway, - if it saves 1 or more cycles a day it will have done its job!

milo...
0
FollowupID: 358747

Follow Up By: Nudenut - Tuesday, Mar 01, 2005 at 08:09

Tuesday, Mar 01, 2005 at 08:09
I can only say ...
its got me buggered why they need to do that..

i wonder if they also have some condenser on the back panel of the compressor compartment?

I dunno............but they, the danfoss comp, do not need it
0
FollowupID: 358774

Follow Up By: Nudenut - Wednesday, Mar 02, 2005 at 08:17

Wednesday, Mar 02, 2005 at 08:17
Maybe i can say something!

Crackles........your not trying to mislead me are you?

Since when could one use outside skin on the auto fridge as the condenser?
"The interior cabinet and the EXTERIOR construction of the AUTOFRIDGE ARE white FIBREGLASS"

No heat transfer thru fibreglass.

This would then suggest that it may have an aircooled condensing unit?....which has a fan!!
0
FollowupID: 358897

Follow Up By: Crackles - Wednesday, Mar 02, 2005 at 21:58

Wednesday, Mar 02, 2005 at 21:58
No I'm not misleading you. If you look at the fridge photo on the link you posted both of the long sides have aluminium panels recessed into the fibreglass. (Darker shade of white) On the 73 litre model they measure 750 X 400 on each side & with such a large surface area to transfer heat may help explain why they are so efficient. They suggest a minimum gap of 40mm around the sides for ventalation.
Cheers Craig..........
0
FollowupID: 358972

Reply By: signman - Monday, Feb 28, 2005 at 10:30

Monday, Feb 28, 2005 at 10:30
If you really want to make a fridge like that perform heaps better, internally mount a finned condensor. Hasn't gotta be big (even about 100mm square) would greatly improve performance. At the moment i think you'll find the case is the condensor- a very cheap and inefficient way to do things.
AnswerID: 100461

Sponsored Links

Popular Products (14)