How to bypass cabin thermostate of AC

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zank (zank) 2011-05-04 05:33:22 +0500 #1

I have a Cultus 2004. AC is stock and is in pretty fine condition.
But it trips on when its just on the verge of chilling.
I have recently replaced a faulty thermostate. Now I think that without thermostat it was better in cooling.
I can manually switch off the AC to prevent icing, not an issue it is.
I have also turned the thermostat knob to the fullest for max possible (clockwise) interval of compressor tripping.

What if I detach the steel coil that goes into the unit from the thermostat? Will this diffuse it? I think it is acting as the cooling sensor...

Thanks.

Vaqas1 (Vaqas1) 2011-05-04 05:42:32 +0500 #2

Yes removing it or pulling it out will defuse it but its better to get a better quality one and adjust it properly.

Icing can be bad for your unit

zank (zank) 2011-05-04 05:51:41 +0500 #3

Thanks yaar. This steel wire just came into my mind when I was writing the thread
Will check by taking it out.
Its not good that the thermostat knob gets to max and the AC still trips very early.
Do you think changing thermostat will help in this concern, extending AC trip interval? It was a 200 rupees item I think...

Regarding Icing - I have drove for about 6 months with a faulty AC thermostat, I used to get know from the air throw that the icing has started to form inside the chamber The air throw loses its pressure. Switching off the AC manually for a minute can get it back again fine. So I'm used to it...
And the car was chilling cool in those days.

faisi001 (faisi001) 2011-05-04 07:29:11 +0500 #4

its not ur thermostat.... its ur high pressure switch which is triping the ac compressor because the head pressure on the compressor increases....u need to get ur ac serviced because u have a chocked condenser or a faulty expansion valve in my opinion

zank (zank) 2011-05-04 07:40:07 +0500 #5

Nope it is the thermostat, I have checked by rotating its adjustment knob, it works on its settings. AC has been recently serviced and checked, only Thermostat was found faulty and replaced with a local one.

zank (zank) 2011-05-04 07:41:41 +0500 #6

@Faisi001
How could I get an idea if its the Compressor safe-switch that is turning the unit off?

faisi001 (faisi001) 2011-05-04 08:04:43 +0500 #7

put the gauge on the suction side and check if the pressure drops till 30psi on idle and if it goes near 60-70 psi on idle then u have a chocked circuit and then u need to get it serviced from a better ac guy who understands refrigeration ......

zank (zank) 2011-05-04 08:46:16 +0500 #8

^ It is same as you told. Checked in day time.

faisi001 (faisi001) 2011-05-04 12:27:58 +0500 #9

then ur expansion valve is stuck halfway or its not working properly please get it changed and ur ac will work fine

Xulfiqar (Xulfiqar) 2011-05-04 13:55:43 +0500 #10

if your system was working on max chill without the stat - and faulty operation with a new Tstat cranked all the way too chill - the person who installed it did a terrible job, its probe is supposed to be suspended in air and its tube buried in one of the fins, I think the probe is probably touching the pipe where the expansion valve just enters the evaporator - its very chilled.

zank (zank) 2011-05-05 04:24:44 +0500 #11

Oops you are right, I think I pushed both into wrong places while checking up myself.
Thanks, I will check on this, will turn on the AC and make sure the T-stat and its steel tube goes in correct places.
How do I know that the tube is going to the fins?

rustam54 (rustam) 2011-05-05 04:42:04 +0500 #12

@Zank

Can you please post the pic describing the location of the thermostat. I am having that same early tripping problem. Mechanic says that the stock thermostat doesnt have a knob to regulate the temprature. You have to replace the thermostat with an aftermarket one. And I dont trust him....

Also mention where is it located in a cultus.

zank (zank) 2011-05-05 08:43:58 +0500 #13

sorry don't have a cam for now. It is located beneath the dashboard, right with the chilling chamber. Ita a device with which a steel cable will be attached. It does have a knob infront that is adjustable.

Xulfiqar (Xulfiqar) 2011-05-05 12:49:12 +0500 #14

the original thermostat that come installed by the factory on the evaporator are non-adjustable, some older ones were - but had a tiny screw to adjust very slightly, the aftermarket ones have a giant knob for this purpose.

Xulfiqar (Xulfiqar) 2011-05-05 12:52:15 +0500 #15

The only correct way is to install it when the evaporator is out of the car, you can try to work by feel and just leave it in a braid fashion somehow suspending it in air.