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Brian_UK
06-08-2001, 09:21 PM
I keep looking at this sub-section and no-one, including myself, seems to have come up with a request for anything tecthnical .

It is making me wonder whether in fact there is anything technical about A/C or are we all too clever for our own good?

Most of the potential problems have propably already been discussed elsewhere under TEVs or cap tubes and of course filter/driers.

I suppose the tricky bits are the electronics and as most people just replace a faulty part you can't really call changing wires and plugs technical can you?

BritCit_Juve
11-12-2001, 10:12 PM
I just thought you might be getting lonely in here. Changing wires isn't technical thats why there are so many electricians about.
Problem with this area is that most questions you would post here you would go to the manufacturer for. Maybe you needto change iit to Obscure technical to a/c or somesuch.

Brian_UK
13-12-2001, 12:52 AM
Originally posted by BritCit_Juve
I just thought you might be getting lonely in here. Changing wires isn't technical thats why there are so many electricians about.Whoa there BCJ, you'll be upsetting the natives :D

Mind you, I caught myself out the other day by listening to the account of an ac fault and not checking it completely myself.

A unit had been installed (2nd hand from client) and worked fine, then it had to be moved after which it didn't work. The report said that it HAD worked in the new position but didn't now.

Following what service info I had the fault appeared to be in the outdoor control board. Due to the age of the unit I recommended that the indoor board was replaced as well. So I replaced the outdoor board, same fault code shown but different signal voltages from the last test. So maybe something was going right.

Anyway, swapped the indoor board and still the damn thing wouldn't work :mad:

Rechecked all the cabling again and found that the installer had wired in a condensate pump putting the neutral into the interconnecting signal wire. So that's were my volts dissappeared too.

Problem solved, unit working, crept away very quietly :D

Mike Hopkins
13-12-2001, 04:43 AM
Well maybe this would be the area to post on some of the many electronic or maybe control problems that are frequently encountered in AC/ Fridge work. I have heard stated that 90%
of service related problems are electrical / electronic. Somehow
that has not computed into fact for me but then I haven't done a technical study on it, just going by gut feeling of what I have had to deal with. But I do have some AC related electric/electronic nitemares to share.
Mike Hopkins

frank
13-12-2001, 09:41 PM
Lets hear them Mike - you start the ball rolling and we will all join in;)

Mike Hopkins
14-12-2001, 01:15 AM
Uh Oh! Now I'll have to think back a little and come up with some good ones for you. One common problem I have seen is where you get a call with the machine down on so and so fault. Arrive and find that the fault cannot exist for the condition operator is describing. At least in your mind it can't. But never say never.
On these newer machines and somewhat the older ones with micro processor controlled functions I have seen little shorts where the voltage was drawn down causing the micro to fault on
whatever it could come up with and the real problem be something else. Like wet connections on sensor plugs or flow switch connections wet from condensation. I did have a machine recently that was showing a fault on the to process sensor.
Micro looks at value and compares to known values, if not within
parameters, indicates fault. Well the plug connections to the sensor happened to be under suction side of 25 HP Copeland compressor doing 1*C leaving brine temp. and she sweated a bit and soaked the connector causing shorted sensor. A little contact spray and some ziplock bags and wire ties and were off and chilling again. That was easy one, unlike troubles mentioned above. I'll go and have a look see at the old service log and see what we can come up with.
Mike Hopkins

BritCit_Juve
14-12-2001, 06:45 PM
The unfortunate thing is that the manufacturers keep their tips and tricks secret. They give some information in the manuals which you just cant get hold of and none on the unit.
At least they are starting to get the message these days though, still if they give us all the info I suppose they will start to feel they can charge a 1/min for the privalege.
Still they could at least make the wiring diagrams legible, there's nothing worse than trying to decipher the wiring on a unit you've never seen before especially when you need a magnifying glass to see it.