Manifold

[gazza666]

Hi
I want to recharge the air con on my range rover the system has been opened up for repair
I have a vacuum pump and a manifold gauge set
My question is that the manifold gauge I have is a refco gauge with 5 hoses
It does R22 R407c and R410a with connections for these
My car is R134a so if I buy two new hoses and a couple of R134a couplers
Can I use this gauge for R134a I know the pressure temp scale won’t be there?
But I can still use the pressure reading of the gauge Hi and Low side
Will this be ok

[Gingerair]

The short answer is yes, although the lines for R410a fittings are different to others..

If your system has been 'open' for any extended period, the oil contained in the system may have degraded.

You should also only handle refrigerants if qualified..

[monkey spanners]

What Gingerair said, also you should be leak testing with nitrogen to check for leaks before vacuuming and recharging.

Some fresh oil in the vac pump will ensure it can pull a decent vacuum (proper vac pump oil)

Make sure the condenser fan works too, these system can develope very high pressures in fault condidtions.

[gazza666]

The system was opend up not because ther was a fault with the aircon system it was a fault with the heater motors

I will add a bit more oil
the only trouble is the compressor will not work because there is no sharge in system will have to wire compressor direct to batery to start it up to suck some gas in

[Gingerair]

You shouldn't have to do your thing with wiring the compressor directly to the batt...your starting to scare me Gazza :rolleyes:

As MS said, first do a pressure test with OXYGEN FREE nitrogen to check for leaks, then a vac out.
It's then very important that the refrigerant charge is weighed in as per manufacturers spec.
If all the specified charge weight cannot be added due to the pressure equalising out, then the car can be started, the a/c turned on & the required remaining charge weighed in via the low pressure (blue) side of the system..

[gazza666]

Ok do a pressure test with OXYGEN FREE nitrogen to check for leaks, then a vac out.
Ok I know the refrigerant charge and can weigh it
Add the refrigerant to the high pressure red side (obviously with compressor not running with ignition switched off)

If all the specified charge weight cannot be added due to the pressure equalising out, then the car can be started, the a/c turned on & the required remaining charge weighed in via the low pressure (blue) side of the system

Ok got that you have been very helpful

[tbirdtbird]

First we'll assume the system has been open only a short time and that it is not contaminated. You should not need to add more oil; remember the entire system only holds 8 oz of oil max, unless you know for sure that oil leaked out. You don't need to buy more hoses, just the 134 adapters at the auto parts store. In the US anyone can buy small individual cans of 134 to charge the system, no licensing required, again at your local auto parts store. The amount of charge should be in the service manual, but if not charge to a nearly full sight glass, usually located on top of the receiver. Charge on a hot day at least 80 degrees or you will overcharge, else leave some bubbles in the sight glass. Charge and check your glass at 1500 RPM, have the A/C fan on high with the doors open and the temp as cold as the setting will allow. Charge in small amounts very slowly to allow the system to equalize, it can easily take 15 min or more. If you go too fast you will overcharge. As you are charging the pressure in the system will begin to rise and the compressor will start up on its own. Do not try to manually start it. Watch your low side pressure you are advised to not go over 30-32 psi. I never connect the high side gauge on cars, I don't need it, and for a novice the high side can be dangerous. Besides, some cars do not have high side access anyway. As has been stated be sure to pull a good long vacuum first 30-60 min. Once you are done you can check the performance of the system for a few days and can always put a little more refrigerant in later to top it up if necessary. I would advise a totally clear sight glass only on a 95-100 degree day. I have seen too many cars over charged and damage the compressor. At lower temps and idle speed there are normally lots of bubbles in the glass. If you are not certain of any parts of this then have it done by a pro.

[tbirdtbird]

Ok do a pressure test with OXYGEN FREE nitrogen to check for leaks, then a vac out.
Ok I know the refrigerant charge and can weigh it
Add the refrigerant to the high pressure red side (obviously with compressor not running with ignition switched off)

If all the specified charge weight cannot be added due to the pressure equalising out, then the car can be started, the a/c turned on & the required remaining charge weighed in via the low pressure (blue) side of the system

Ok got that you have been very helpful

Yikes you stuck that post in there while I was typing mine.

"Add the refrigerant to the high pressure red side (obviously with compressor not running with ignition switched off). If all the specified charge weight cannot be added due to the pressure equalising out, then the car can be started, the a/c turned on & the required remaining charge weighed in via the low pressure (blue) side of the system"

Do not do this. Look at my last post. And always charge thru the low side. You are scaring all of us now.

[gazza666]

Yes I can understand what you are saying
Just buy the r134a coupler for my hose don’t bother with high pressure
Weigh the refrigerant charge
Use the receiver glass for checking charge do it slowly don’t overfill
Work to pressure of about 30 psi
Compressor will start on its own when pressure builds up

Two way to do the same thing but witch is the right way and which is the safest

[gazza666]

Sorry for scaring everybody
I thought you could charge through the high side as long as the compressor was not running
I will post exactly what I am going to do before I do it
And if you give me the all clear I will go ahead
Believe it or not I have been reading about this subject for the past 5 days
So I do know a little bit
But it is good to ask the experts

[tbirdtbird]

OK I re-read Gingerair and that info is OK. I wanted to give more detail and cautions. At first I thought you were charging thru the hi side with the compressor on which can cause a nasty explosion

[Gingerair]

It's ok, i scare myself all the time.. :eek:

Prob best you familiarise yourself with how the manifold set valves work as well before attempting the job..

There may also be examples on you-tube but i'm not sure how acurate they'll be..

[gazza666]

Ok
Looking at all the posts this is what I am going to do to recharge my range rover from empty
The refrigeration weight is 1250g +/- 40g
I have 3 tins of r134a 340 g in weight =1360g so I need to put in 3 tins + 230g I can weigh that
Will probably put in about 1210g can always add bit more another day give it chance to settle
Next step
Cant do pressure test with OFN haven’t got any
I have a master cool 3 cfm vacuum pump so will give it a good vac hold the vac for a good time ,if ok vac a bit more that will have to do
Next step
Two different ways of doing this 1st way
Charge through high side initially (compressor not running) when cant charge no more shut high side valve off start engine turn ac on max ,continue to charge on low side till all the charge as gone
2nd way
Charge on low side start engine ac on max compressor will not run because no charge in system
Add refrigerant slowly a bit at a time when the pressure builds up compressor will kick in continue to add charge slowly till all charge has gone can look at receiver sight gauge for checking charge but if I have weighed all the refrigerant first there will be no guesswork

The way I fancy doing it is to charge on the high side first my logic in this, is if the compressor is not running then can’t do any damage
Then continue on low side when the compressor should come on and then continue the refrigerant charge

If this is wrong or can suggest better way let me know

[Gingerair]

Basically you've got the jist of things Gazza..

So when you find someone that is qualified to help.......

With the engine stopped..

If you insist on using the high side port..

If as you said, you have a 4-valve manifold set, vac out through both the high & low sides, also attach line to 134a bottle & vac out line to bottle at same time.
Then get them to carry out a proper vac-rise test, if it passes, add the gas to both sides. If you get the full charge in then all good, but either way close the manifold high & low side valves before starting the engine.

Leave high side manifold valve closed..

If any additional charge required charge through low side with compressor running..

Or as T-Bird said, you don't really need to connect up to the high side at all..

When running check all joins with leak detector (soapy water)

I normally keep away from anything with 3 sixes, but let us know how you get on..

Good luck..

[gazza666]

Yes I like your idea charge bothe sides at the same time compressor not running makes sense
I only have a two way manifold not four way

[gazza666]

when I charge into bothe ports would it be best to hold the can upside down
so as to get the juce in there or leave the can upright and just let the vapour in
I know you dont turn the can upside down normally with the compressor running but when not running will this be ok

[The bone]

when I charge into bothe ports would it be best to hold the can upside down
so as to get the juce in there or leave the can upright and just let the vapour in
I know you dont turn the can upside down normally with the compressor running but when not running will this be ok
think you better find an engineer.very scary situation

[tbirdtbird]

There is a problem with the math here
"I have 3 tins of r134a 340 g in weight =1360g so I need to put in 3 tins + 230g I can weigh that "

I'd leave the cans upright.
If you do connect to the high side when the engine is off, be sure to close the hi side manifold valve and *disconnect* the hi side hose before you start the engine.

[gazza666]

What I should have said I have 5 tins of R134a only need 3 tins + a bit of the other ,can weigh that little bit ok

thanks for your help

stop saying its scary you are begining to scare me if compressor is not running cont do any harm

I will not hold the can upside down but should I put it in a bowl of boiling water to aid the gas flow LoL
i am only joking but I have read that you can put the can in some warm water that helps get the gas in there

I will let you all know How I have done
my next post wil be from hospital LOL

just joking i am quite confident
thanks

[paul thompson]

:rolleyes::rolleyes:
What I should have said I have 5 tins of R134a only need 3 tins + a bit of the other ,can weigh that little bit ok

thanks for your help

stop saying its scary you are begining to scare me if compressor is not running cont do any harm

I will not hold the can upside down but should I put it in a bowl of boiling water to aid the gas flow LoL
i am only joking but I have read that you can put the can in some warm water that helps get the gas in there

I will let you all know How I have done
my next post wil be from hospital LOL

just joking i am quite confident
thanks:rolleyes:BANG BANG , get a auto a/c engineer to do the work , it wont cost that much and you will be safe , plus you are not supposed to handle refrigerant if you are not , trained and hold a safe handling cert , :rolleyes:

[gazza666]

I always say if you want a job done right do it yourself
To get a safe handling cert don’t mean much I could get one if I paid the money
I might know the fundamentals but still would not have the experience
I have paid out about £250 to buy the equipment to do it myself
But I could have paid about £50 for somebody else to do it
But I am the sort of person to do things myself
That’s the only way you learn
Might even get the certificate and take it up as a hobby doing car aircon

[tbirdtbird]

As previously stated in the US anyone can buy small cans of 134 at the auto parts stores. IDK about europe.

[tbirdtbird]

BTW let us know how it goes

[gazza666]

I am just getting my gear together need to get a two 134a couplers
to fit to my hoses
I have a mastercool 3cfm vac pump put fresh oil in it
connected it to the manifold gauges put my finger over the lowside hose opend the valve and it sucked to 30 on the gauge
I was qouite suprised than I could keep my finger over the pipe I thought it would suck a lot more than that
what do you say

[monkey spanners]

I am just getting my gear together need to get a two 134a couplers
to fit to my hoses
I have a mastercool 3cfm vac pump put fresh oil in it
connected it to the manifold gauges put my finger over the lowside hose opend the valve and it sucked to 30 on the gauge
I was qouite suprised than I could keep my finger over the pipe I thought it would suck a lot more than that
what do you say

Even a full vacuum is only -15 pounds per square inch since that is all the air there is!

[Makeit go Right]

Double check: Gloucestershire-UK, June 2010.


“I always say if you want a job done right do it yourself
To get a safe handling cert don’t mean much I could get one if I paid the money
I might know the fundamentals but still would not have the experience
I have paid out about £250 to buy the equipment to do it myself
But I could have paid about £50 for somebody else to do it
But I am the sort of person to do things myself
That’s the only way you learn.”

"Believe it or not I have been reading about this subject for the past 5 days
So I do know a little bit."
DIY fridge work is okay in many parts of the world but in the UK it is illegal unless the person also gets himself qualified at least. The OP has not passed a Safe Handling Assessment (and has no real experience). It would be illegal for him to repair a fridge system or play around with refrigerant.


“I want to recharge the air con on my Range Rover after the system has been opened up for repair, not because there was a fault with the aircon system it was a fault with the heater motors.”
Presumably it was the OP who opened up the system for repairs and I strongly suspect that any refrigerant would have been released/vented and not properly recovered. Presumably the unqualified OP also carried out the fridge repair work – also illegal.


“I can’t do pressure test with OFN; I haven’t got any.” (or a regulator etc)
OP plans to skip the OFN pressure test and check for fridge leaks by charging the system and then see if any refrigerant leaks out. However, it is illegal to charge/recharge a system to use the refrigerant as a means of leak detection.

This is all very scary. Not just the danger to OP who could hurt himself -- but also from a legal aspect (and save the planet thing), running the risk of mega fines if discovered by the authorities.

[Gingerair]

Sensible & safer option for the OP-

http://www.ellistraining.co.uk/courses/air-conditioning/mobile-air-conditioning

[tbirdtbird]

Legality and safety may not be the same. OP was clearly determined to do this. Safety issues were addressed by several responders.

[gazza666]

I never opened up the system for repairs I bought the car and it had no refrigerant in it
The problem was the heater motors not the a/c so there is no reason why it should not be ok now

I do not plan to charge the system and check for leaks
I can’t do a OFN test but I can leave it under vacuum for a period of time
I would never charge the system knowing it would leak

[gazza666]

I dont fancy paying £375 + vat for City and Guilds 5101