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AC Compressor

Is this the switch? If it is, I only have 2 wires.

20170803_202044.jpg
 
That is the low refrigerant pressure switch by the looks of it taking it's reading from the high side it does now allow the compressor to engage if you have a leak.

Unsure if it is trinary though, so it could control via the switch body for high and low. The 80 version is and has 4 terminals but only two are used for low pressure to control the compressor activation, I use the redundant pair to control the engine cooling fan.

Serious over pressure would result in the compressor locking and burning out the belt long before an 'O' ring leaked.

Regards

Dave
 
That is the low refrigerant pressure switch by the looks of it taking it's reading from the high side it does now allow the compressor to engage if you have a leak.

Unsure if it is trinary though, so it could control via the switch body for high and low. The 80 version is and has 4 terminals but only two are used for low pressure to control the compressor activation, I use the redundant pair to control the engine cooling fan.

Serious over pressure would result in the compressor locking and burning out the belt long before an 'O' ring leaked.

Regards

Dave
The pressure switch in the picture is on the HP side, the cap has an H on it and the pipework is skinny and metallic. On the 80, certainly on mine at least, there's a pressure relief valve so there's double protection and if all else fails the clutch or belt would slip. The HP switch is there for if the system is unable to lose enough heat through the condenser, either through high ambient temperature, lack of airflow or reduced condenser surface area. On rare occasions it could be due to a blockage, which is usually caused by moisture in the system freezing as it goes through an orifice into the cold side.

Alas that looks like it's not the same switch. In fact the condenser is different to the one I saw which had a common block for both connections to the pipework.

Thanks for posting.

I'll have a look at the link, thanks for that and thanks for trying to post CG. Could there be a hole in your photobucket?
 
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It is not uncommon for a low refrigerent switch to be on the high side, I canno remember seeing a low pressure switch elsewhere on a 120.

The 80 has the blow off valve and the low pressure by the left battery, compressor lock seems to be a particular trait of the 80, I have yet to see a blow valve actually blow.

Regards

Dave
 
You have a point there Dave, I've only seen a low pressure switch on the Smart Car AC. There's always a switch on the high side so in that case I see what you are saying, there's a switch to save the compressor from lack of refrigerant combined into the high side switch switching to earth.
 
Just changed the compressor over. it was a lot easier than i thought. Took the airbox out of the way and you could get at all bolts/connections easily. just waiting for the dryer to turn up and il change that over and get it re gassed. il get some pics of the dryer when i take it out for future reference. It looks like i need to order a new tool to get the dryer bottom cap off as my allen keys are too small :icon-biggrin:
 
Sorry to jack this thread again, but I had my AC system "vacced" today for one hour, and re-gassed, full Monty, and for the moment, it's 35C outside and bloody cold in the truck :dance:.

We'll see how long it lasts... :whistle:
 
Sorry to jack this thread again, but I had my AC system "vacced" today for one hour, and re-gassed, full Monty, and for the moment, it's 35C outside and bloody cold in the truck :dance:.

We'll see how long it lasts... :whistle:
Nitrogen flush?
New drier?
 
Just changed the compressor over. it was a lot easier than i thought. Took the airbox out of the way and you could get at all bolts/connections easily. just waiting for the dryer to turn up and il change that over and get it re gassed. il get some pics of the dryer when i take it out for future reference. It looks like i need to order a new tool to get the dryer bottom cap off as my allen keys are too small :icon-biggrin:
Just make sure you keep the system as sealed as you can. Tape up any open ends straight away, even if you're going to onlybhave them open 10 minutes. Stops moisture and dirt getting in. Not essential but good practice.
 
Just make sure you keep the system as sealed as you can. Tape up any open ends straight away, even if you're going to onlybhave them open 10 minutes. Stops moisture and dirt getting in. Not essential but good practice.

At the moment i have no open ends, its not vacced but all joints are complete. Im waiting for my new drier to turn up, it was meant to be here monday but its been delayed. Once i have the new drier im going to book it in for the re gas and change it over that morning.
 
In danger of sounding like a stuck record...but.

put 2 oz of pag oil in the new dryer.
 
Nitrogen flush?
New drier?

I don't know about a nitrogen flush, but it had a new dryer last summer.

I've a 500 km drive coming up on Saturday and the forecast is 35C so I'm interested whether it goes the distance (and return on Tuesday), we'll see.

He put back pag oil and 134a so it's fingers crossed.
 
Let's hope it's sorted it Clive. Thing is, if it's moisture in the system as it appears to be, then that indicates the drier has done all it can. Hopefully the vacuum will have pulled out enough moisture for it to run successfully.
 
I would say so SC. did you rotate it by hand and watch the oil practically fill the reservoir at the top? IMO and that of my fridge engineer mate, no further oil needs adding with a new compressor. I think CG was meaning for Clive if replacing the drier to add oil to compensate for what's likely to have been removed with the drier.
 
I would say so SC. did you rotate it by hand and watch the oil practically fill the reservoir at the top? IMO and that of my fridge engineer mate, no further oil needs adding with a new compressor. I think CG was meaning for Clive if replacing the drier to add oil to compensate for what's likely to have been removed with the drier.

In my case, the dryer was installed by the AC maintenance guy, with the equipment. I had to presume he would add oil as required, when replacing a part....

Too many assumptions, I know, but I'm just a pen pusher...
 
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