Thread: ACT – Anyone able to help test A/C pressures on Disco 4?

Originally Posted by tankwaste

Hi all,
I’m chasing a bit of help with the A/C on my Discovery 4 (MY13 SDV6).

The system has been re-gassed recently and the compressor clutch is engaging, but I’m only getting slightly cool air rather than properly cold. Before I start throwing parts at it (control valve, compressor, etc.), I’d really like to see what the high and low side pressures are doing to diagnose it properly.

Is there anyone in the ACT who has the proper manifold gauges / equipment and would be willing to help check pressures? Happy to bring the car to you and shout coffee/beer for your time.
Trying to be methodical about this rather than guessing.
Thanks in advance ?

I just purchased another set last week (my last set is just leaky junk, it was the cheapest stuff I could find on ebay ... probably 20years ago ... so not the end of the world). Anyway, it was $68.00 delivered to my doorstep. So its probably worth buying your own set ? I'd lend you mine, but your a bit far away. Postage there an back would be the same cost as buying your own set!

seeya
Shane L.

Agree with Shane. Did same.
Had my D2a to do as the primary reason for getting gauge set. Doesn't have to be elite/pro stuff. Had no idea how to operate it, and gas the system, but reading up here and there, Utube videos ... etc etc. I used Hychill to recharge the D2a.

2x Hychill bottles, vac pump, and gauges set cost less than $200, and cheapest AC service I could find near me(within 100kms) was $250.

Obviously the hardware will do basically any AC system ... but more importantly with 2 bottles of Hychill, I did D2a, brothers Falcon, nephews D2a(but it has a leak, so needs more work) and my Peugeot 3008, and I think I may have enough for one more vehicle system left.

Brother is currently renovating a house .. pretty much full rebuild. Part of that reno is installing split AC systems. Doing all work ourselves .. handy to have gauges to do the pressure leakdown testing. 3 of 4 units all good from the start, but we totally botched one unit install. ... long story ... but the point here is that once we found the problem ... having gauges to check leaks ... handy to have for not a lot of money.
More importantly .. don't have to rely on specialist techs that don't really care about small jobs.

Originally Posted by AK83

Agree with Shane. Did same.
Had my D2a to do as the primary reason for getting gauge set. Doesn't have to be elite/pro stuff. Had no idea how to operate it, and gas the system, but reading up here and there, Utube videos ... etc etc. I used Hychill to recharge the D2a.

2x Hychill bottles, vac pump, and gauges set cost less than $200, and cheapest AC service I could find near me(within 100kms) was $250.

Obviously the hardware will do basically any AC system ... but more importantly with 2 bottles of Hychill, I did D2a, brothers Falcon, nephews D2a(but it has a leak, so needs more work) and my Peugeot 3008, and I think I may have enough for one more vehicle system left.

Brother is currently renovating a house .. pretty much full rebuild. Part of that reno is installing split AC systems. Doing all work ourselves .. handy to have gauges to do the pressure leakdown testing. 3 of 4 units all good from the start, but we totally botched one unit install. ... long story ... but the point here is that once we found the problem ... having gauges to check leaks ... handy to have for not a lot of money.
More importantly .. don't have to rely on specialist techs that don't really care about small jobs.

You will need a different guage/manifold set for split systems (the connector are different to R12/R134a). I have a nitrogen bottle here that I recharge suspension spheres with. I've made a really dodgy "valve" that allows me to dump nitrogen into the A/C systems. You put is for example 150psi of nitrogen, and see if the gauges drop over time. If they don't, no leaks, if they do, you can use soapy water in a spray bottle to attempt to find the leaks

seeya
Shane L.

Originally Posted by AK83

Brother is currently renovating a house .. pretty much full rebuild. Part of that reno is installing split AC systems. Doing all work ourselves .. handy to have gauges to do the pressure leakdown testing. 3 of 4 units all good from the start, but we totally botched one unit install. ... long story ... but the point here is that once we found the problem ... having gauges to check leaks ... handy to have for not a lot of money.
More importantly .. don't have to rely on specialist techs that don't really care about small jobs.

Two issues here,first it is illegal,if not qualified,but who really cares?
Not me,or for that matter anyone else.

Secondly,no warranty on the units,as not installed by someone qualified.
Sure,they are pretty reliable,but we have seen many failures during the warranty period.

Originally Posted by DoubleChevron

You will need a different guage/manifold set for split systems (the connector are different to R12/R134a). I have a nitrogen bottle here that I recharge suspension spheres with. I've made a really dodgy "valve" that allows me to dump nitrogen into the A/C systems. You put is for example 150psi of nitrogen, and see if the gauges drop over time. If they don't, no leaks, if they do, you can use soapy water in a spray bottle to attempt to find the leaks

seeya
Shane L.

Just use cheapo adapters,which are available everywhere.
Use whatever flexible lines you have and get the correct adapters.

I hope you are using a reg on the nitro bottle......

Too much pressure in the lines can push the nitrogen back into and mix with the refrigerant in the AC,that is if it is a pre charged unit.

Seen that happen many times.
We never pressure test the lines if they are connected to a pre charged AC unit.

I keep 3 sets of gauges. One for old R12/Hydrocabon systems with mineral oil, one for r134a system with PAG oil and one for more modern r410a/R32 systems with POE oil.
That's a convenience thing to save having to wash the hoses/manifolds out. Each manifold/hose has a standard 1/4" SAE flare. I have adapters for r134a and the 5/16" flares on the newer systems.

I have a 1/4" flush gun and used to wash the hoses out when I'd finished, but it turned out to be much less hassle just to pick up extra manifolds/hoses when they were on sale.
PAG oil is work of the devil, but it is what it is.

I used to keep a nitrogen bottle around and a reg that could do ~500PSI. As I've always got Argon (thanks Bunnings swap and go) for the TIG, I replaced the inlet stem on one of my Nitrogen regs with one from an Argon reg, so I can use Argon if I need to pressure test. Bye bye yearly BOC rental and hello being able to get gas at 6PM on a Sunday night.

Originally Posted by scarry

Just use cheapo adapters,which are available everywhere.
Use whatever flexible lines you have and get the correct adapters.

I hope you are using a reg on the nitro bottle......

Too much pressure in the lines can push the nitrogen back into and mix with the refrigerant in the AC,that is if it is a pre charged unit.

Seen that happen many times.
We never pressure test the lines if they are connected to a pre charged AC unit.

Nah ... that's for cowards .... Seriously though, I'm using a teconsir sphere recharger

https://www.tecnosirstore.com/epages...Products/C720S

its designed to run at bottle pressure (terrifying right?). However the front Citroen CX spheres have a 75 bar pressure (nearly 1100psi). there is little point using a regualator, the bottle pressure is about 200bar from memory. The lines are rated at 250bar working pressure on the regasser. It easily "dribbles" nitrogen in allowing me a add pressure to an A/C system.

that is interesting about your split system pushing the charge out. I have only done my own stuff, but several times I've found leaky connections when pre-charging with nitrogen and checking for loss of pressure. I never really go higher than 150psi. I can't imagine that would push past the service valves on the outside unit (the refrigerant can be close to 100psi sitting there, with everything off).

seeya
Shane L.

Originally Posted by DoubleChevron

that is interesting about your split system pushing the charge out. I have only done my own stuff, but several times I've found leaky connections when pre-charging with nitrogen and checking for loss of pressure. I never really go higher than 150psi. I can't imagine that would push past the service valves on the outside unit (the refrigerant can be close to 100psi sitting there, with everything off).

seeya
Shane L.

Standing pressure using R32 would be close to 300PSI on a 30 degree day,so you should be fine at 150.

We have seen it done by others,and then we get a warranty call.....

Probably not using a nitro reg,and putting bottle pressure into the lines

We generally never pressure test them anyway,for the few we do these days.
Do good flares,use oil on the face and behind the nut,tighten correctly,release refrigerant after vac,go around each flare with electronic sniffer,all good.

Talking about Nitrogen and regulators,years ago in another life i did some work with supermarket refrig.
The boys were doing an install at a new store and went to lunch,they left a nitrogen bottle and reg attatched to a system.
Who did what we will never know,anyway,they were outside in the carpark and heard a huge explosion,one of the compressors in the system,a Semi Hermetic Copeland,exploded.
The whole plant room was destroyed,luckily no one was there at the time.
Now you know why i am always very cautious with nitrogen.

EDIT:And to add,back in those days i think it was a 5/8 or it could have been 3/4 male flare fitting screwed directly into the Nitro bottle.So some used this with a fitting with a male 1/4 flare on the end.
The bottles these days,same as Oxygen,are different.