A/C servicing; vacuum, oil and charge system? (4 Viewers)

[OEMGUY0720]

Check / service the AC compressor’s clutch as well. Mating surfaces should be clean and good to ensure it engages and is not stucked.

 

[flintknapper]

I was thinking the positive pressure, shown on manifold gauge, when AC running. Was indication of positive pressure, for both LOW & HIGH sides. That the can's pressure, was greater than that in low side of AC system.

The pressure reading IS positive pressure. The 'vapor' pressure in the can (depending on ambient temp) is roughly 30-40 psi (for R134a). So when the system has been freshly evacuated, pumped down and still under vacuum, the can pressure is greater and will readily go into the system (on its own). The compressor would not even have to be running. But once the gas pressure has equalized (between system and can), that flow can no happen.

This is where the compressor comes in. On the low side (suction side) the compressor creates a low pressure area that the refrigerant is able to travel to (whether that pressure is 5 lbs or 105 lbs, it just needs to be positive pressure). You would never empty a can (except under system vacuum) by can pressure alone.. The compressor needs to be running and creating the low pressure area (we refer to as suction).

The pressure reading you are seeing is isolated from the suction action by the reed valves/plates in the compressor head, not unlike a check valve.

 

[2001LC]

Check / service the AC compressor’s clutch as well. Mating surfaces should be clean and good to ensure it engages and is not stucked.

New OEM.

The pressure reading IS positive pressure. The 'vapor' pressure in the can (depending on ambient temp) is roughly 30-40 psi (for R134a). So when the system has been freshly evacuated, pumped down and still under vacuum, the can pressure is greater and will readily go into the system (on its own). The compressor would not even have to be running. But once the gas pressure has equalized (between system and can), that flow can no happen.

This is where the compressor comes in. On the low side (suction side) the compressor creates a low pressure area that the refrigerant is able to travel to (whether that pressure is 5 lbs or 105 lbs, it just needs to be positive pressure). You would never empty a can (except under system vacuum) by can pressure alone.. The compressor needs to be running and creating the low pressure area (we refer to as suction).

The pressure reading you are seeing is isolated from the suction action by the reed valves/plates in the compressor head, not unlike a check valve.

Well, I may have introduced air. I'm thinking perhaps I should re- vacuum & charge.

_________________________________

As mentioned. My yellow fill line was leaking at the point it threaded to can adapter. Which I could only hear while filling (liquid) first can into HIGH side, engine/AC off. I did sung it down, and seems to stop leaking (hissing). But I've some concerns, it still leaked a bit. So I may have introduced airr, as can liquid/pressure neared its end.

I used, the HF manifold I bought 7 years ago when I started this thread. Actually is was, me first time vacuuming & charging. Since then Colo has mandated, resealable cans must be used. So I've been using an adapter on can and brass piercing valve on it. The yellow hose.

So I'm thinking about buying a new set up.. To do a re charge.

 

[flintknapper]

New OEM.

Well, I may have introduced air. I'm thinking perhaps I should re- vacuum & charge.

_________________________________

As mentioned. My yellow fill line was leaking at the point it threaded to can adapter. Which I could only hear while filling (liquid) first can into HIGH side, engine/AC off. I did sung it down, and seems to stop leaking (hissing). But I've some concerns, it still leaked a bit. So I may have introduced airr, as can liquid/pressure neared its end.

I used, the HF manifold I bought 7 years ago when I started this thread. Actually is was, me first time vacuuming & charging. Since then Colo has mandated, resealable cans must be used. So I've been using an adapter on can and brass piercing valve on it. The yellow hose.

So I'm thinking about buying a new set up.. To do a re charge.

Yes Sir, good plan. Be sure your equipment is working properly and of course take your time.

A/C work is not something you want to do twice. Let us know how the second attempt goes.

I'd like to see (at idle) vent temps around 45°F, improving to about 40 °F vent temps at highway speed. IF you are not in an extrememly hot climate area, this should be acheivable.

 

[2001LC]

Yes Sir, good plan. Be sure your equipment is working properly and of course take your time.

A/C work is not something you want to do twice. Let us know how the second attempt goes.

I'd like to see (at idle) vent temps around 45°F, improving to about 40 °F vent temps at highway speed. IF you are not in an extrememly hot climate area, this should be acheivable.

Any equipment you care to recommend?
Be nice, to have new seals every ~7 years or so. A manifolds, that offers seal kits, would be on short list for sure. Since I don't use that much and take good care of my tools. Just replacing seals, would save from tossing tools in the trash.

Or should I just head over to Harbor Freight, buy whatever they've on hand?
Last I looked, theirs (HF) looked updated.

Does brand of 134a make a difference?
I just used NAPA's

I held about 27PSI vacuum. So my manifold sealed well and vacuum pump worked good. It was the end of my yellow hose to brass tap, where I had leak?
I could just get yellow and tap.

Not much tapper on my tap, and is not made for reseal cans

Above tap to yellow hose end, is where I've a leak.

I had ~51F idling. Which is why I've some concern, air may be in system. I was wondering if I'd see lower temp after some use? As the 4oz I added back in of the 10oz in/from compressor, oil distributed?
As mentioned. The cabin fan sound a bit labored. I was subsequently told, cabin filter replaced very regularly.
Actual AC thermostat, be better. As this one does block air flow a bit.

My pressures seems okay. Sight glass clear, with short burst of bubbles after shut down

 

[flintknapper]

Any equipment you care to recommend?
Be nice, to have new seals every ~7 years or so. A manifolds, that offers seal kits, would be on short list for sure. Since I don't use that much and take good care of my tools. Just replacing seals, would save from tossing tools in the trash.

Or should I just head over to Harbor Freight, buy whatever they've on hand?
Last I looked, theirs (HF) looked updated.

Does brand of 134a make a difference?
I just used NAPA's

I held about 27PSI vacuum. So my manifold sealed well and vacuum pump worked good. It was the end of my yellow hose to brass tap, where I had leak?
I could just get yellow and tap.

Not much tapper on my tap, and is not made for reseal cans
View attachment 3900758
Above tap to yellow hose end, is where I've a leak.
View attachment 3900760

I had ~51F idling. Which is why I've some concern, air may be in system. I was wondering if I'd see lower temp after some use? As the 4oz I added back in of the 10oz in/from compressor, oil distributed?
As mentioned. The cabin fan sound a bit labored. I was subsequently told, cabin filter replaced very regularly.
Actual AC thermostat, be better. As this one does block air flow a bit.
View attachment 3900753
My pressures seems okay. Sight glass clear, with short burst of bubbles after shut down
View attachment 3900752

I'd wager you have some air in the system. If you can find seals for your hose ends, just do that.
27 hg vacuum is probably pretty good (adjusted for altitude, which I don't know? 6,000 ft?).

Be sure to let your pump run long enough to boil off any moisture in the system ( a few hours). Also start with new vacuum pump oil if it has not been changed recently.

ALL R134a is the same (minimum standard) so the NAPA labled brand is fine. Pump the system back down really well. Be sure to close the valves on the manifold AND pump before shutting the pump down, so you don't get any air it the system.

As before, 'purge' the service line of air with each can of refrigerant (so no air gets in the system). A better vent temp thermometer would not be a bad thing.

Let's see if we can get those vent temps in the 45°F range (at idle, system stabilized) this go 'round.

 

[Eyedaho]

I'd wager you have some air in the system. If you can find seals for your hose ends, just do that.
27 hg vacuum is probably pretty good (adjusted for altitude, which I don't know? 6,000 ft?).

Be sure to let your pump run long enough to boil off any moisture in the system ( a few hours). Also start with new vacuum pump oil if it has not been changed recently.

ALL R134a is the same (minimum standard) so the NAPA labled brand is fine. Pump the system back down really well. Be sure to close the valves on the manifold AND pump before shutting the pump down, so you don't get any air it the system.

As before, 'purge' the service line of air with each can of refrigerant (so no air gets in the system). A better vent temp thermometer would not be a bad thing.

Let's see if we can get those vent temps in the 45°F range (at idle, system stabilized) this go 'round.

@flintknapper, what is your technique for purging the service line between refrigerant cans?

 

[flintknapper]

@flintknapper, what is your technique for purging the service line between refrigerant cans?

Great question about a very important step.

First, (for those who don't already know): The reason we purge the service line is because each time it is connected to a can (or canister) of refrigerant, the hose is open to atmosphere. We don't want any air in the A/C system for a number of reasons.

To that end, you will want to 'purge' that line of air before opening any of the valves on the manifold set. By 'purge'...we mean to let some of the refrigerant push the air out.

To do that: With both manifold valves closed (high and low side), connect your refrigerant source (can or canister) to the yellow service line. IF your manifold set has a shrader valve at the service line port, then just press it a few times allowing a small amount to refrigerant to push the air out the line. You are good to go.

IF your manifold does not have a Schrader Valve SLOWLY begin to unscrew/loosen the fitting at the manifold JUST until some of the refrigerant escapes from around fitting, then tighten it back up. You have successfully purged the line.

Be sure to wear safety glasses and gloves and only loosen the fitting enough to allow a small amount of refrigerant to escape. You would not want the line to pop off the manifold set. It would get real exciting, real quick.

 

[Eyedaho]

Great question about a very important step.

First, (for those who don't already know): The reason we purge the service line is because each time it is connected to a can (or canister) of refrigerant, the hose is open to atmosphere. We don't want any air in the A/C system for a number of reasons.

To that end, you will want to 'purge' that line of air before opening any of the valves on the manifold set. By 'purge'...we mean to let some of the refrigerant push the air out.

To do that: With both manifold valves closed (high and low side), connect your refrigerant source (can or canister) to the yellow service line. IF your manifold set has a shrader valve at the service line port, then just press it a few times allowing a small amount to refrigerant to push the air out the line. You are good to go.

IF your manifold does not have a Schrader Valve SLOWLY begin to unscrew/loosen the fitting at the manifold JUST until some of the refrigerant escapes from around fitting, then tighten it back up. You have successfully purged the line.

Be sure to wear safety glasses and gloves and only loosen the fitting enough to allow a small amount of refrigerant to escape. You would not want the line to pop off the manifold set. It would get real exciting, real quick.

Thank you again for another thorough explanation! You contribute so much to these forums.

 

[2001LC]

I'd wager you have some air in the system. If you can find seals for your hose ends, just do that.
27 hg vacuum is probably pretty good (adjusted for altitude, which I don't know? 6,000 ft?).

Be sure to let your pump run long enough to boil off any moisture in the system ( a few hours). Also start with new vacuum pump oil if it has not been changed recently.

ALL R134a is the same (minimum standard) so the NAPA labled brand is fine. Pump the system back down really well. Be sure to close the valves on the manifold AND pump before shutting the pump down, so you don't get any air it the system.

As before, 'purge' the service line of air with each can of refrigerant (so no air gets in the system). A better vent temp thermometer would not be a bad thing.

Let's see if we can get those vent temps in the 45°F range (at idle, system stabilized) this go 'round.

You have any thoughts on 1/4 turn manifold gauge valves?
The full turn valve style, are easy to adjust flow up slowly. Are the 1/4 turns!


-------------------------------------------------
I stop at HF yesterday. Look over their two brands of A/C Manifolds and can tap.

The R134a self-sealing or reusable cans tap. Has improved tapper. Which was what I felt, one one of my issea resulting in leak. It also eliminates the need for price tap adapter used on non resealable can tap.
$8.

They had the same brand manifold I bought 7 years ago. As I thought, was upgraded. Number one, it has a seal in the yellow line vac pump/can tap end. Same 2% accuracy. Looks good for only $65.

They did have a manifold kit, that comes with extra O-rings. But looking a OM PDF parts schematic. It has other seal, that aren't included nor is HF currently offering. Also a with tap, which should mate to hose perfectly, since included. It has 1/4 turn valves. Indicates, 1% accuracy in mid halve of gauge. Not sure if 1/4 turn a good thing?
$200 Only 12 reviews (good), and not much in reviews outside of HF web page.

I like the case has room, manifold can be store without removing hoses.

 

[flintknapper]

I have no problem with 1/4 turn valves. Main advantage is 'quick shut off', but typically that isn't something needed.

They would be precise enough if needing to partially open a valve (something that IS frequently needed).

 

[2001LC]

I have no problem with 1/4 turn valves. Main advantage is 'quick shut off', but typically that isn't something needed.

They would be precise enough if needing to partially open a valve (something that IS frequently needed).

Not a lot of reviews on that ICON manifold with 1/4 turn. Just 12, in HF web page. 11: 5 star and 1: 4 star review. They saying, solid built.

Which manifold brand, do you like?

For now I bought new tap and yellow hose. But I'm going to update my AC tools. Seems as 100 series fleet ages. I'm seeing more AC issues.

• Like fluid line behind passage front wheel wheel get holes. Seems mud and road wash is getting behind shield and between lines.
• Leaky compressor seals.
• Failing compressors.
• Damage condenser. (not seen one yet. But I surely will)

Top shelve tools, seem worth the investment now.

Thanks to your guidance @flintknapper. I'm gaining a better understanding of system and tools and at servicing them. Thank you!

 

[flintknapper]

Not a lot of reviews on that ICON manifold with 1/4 turn. Just 12, in HF web page. 11: 5 star and 1: 4 star review. They saying, solid built.

Which manifold brand, do you like?

For now I bought new tap and yellow hose. But I'm going to update my AC tools. Seems as 100 series fleet ages. I'm seeing more AC issues.

• Like fluid line behind passage front wheel wheel get holes. Seems mud and road wash is getting behind shield and between lines.
• Leaky compressor seals.
• Failing compressors.
• Damage condenser. (not seen one yet. But I surely will)

Top shelve tools, seem worth the investment now.

Thanks to your guidance @flintknapper. I'm gaining a better understanding of system and tools and at servicing them. Thank you!

If it is your plan to service more A/C systems in the future, then invest in a really good manifold set. It will last you a lifetime (replacing only hose seals from time to time). My personal preferece is Yellow Jacket equipment.

 

[2001LC]

If it is your plan to service more A/C systems in the future, then invest in a really good manifold set. It will last you a lifetime (replacing only hose seals from time to time). My personal preferece is Yellow Jacket equipment.

View attachment 3902381
View attachment 3902382

Almost unbelievable deal (from Grainger) on this set (Ebay), $100.00 less than normal retail.

YELLOW JACKET 49967 Manifold 3-1/8 with Gauges with Hoses for sale online | eBay - https://www.ebay.com/p/710128851

I was so excited. I click; buy it now. Changes to, just the 3 hoses.



2 SOLD

YELLOW JACKET 21986 Hose Set, 72 in L, Blue/Red/Yellow 38D875​

$122.71

 

[flintknapper]

I was so excited. I click; buy it now. Changes to, just the 3 hoses.



2 SOLD

YELLOW JACKET 21986 Hose Set, 72 in L, Blue/Red/Yellow 38D875​

$122.71

Well....that would explain the low price. They show and mention the manifold set in the ad. So apparently misleading. Sorry for the disappointment.

 

[2001LC]

Well....that would explain the low price. They show and mention the manifold set in the ad. So apparently misleading. Sorry for the disappointment.

Likely, just glitch in listing software and/or who inputted.

The Yellow Jacket 49967. Doesn't come with anything, other than manifold and hoses. Like 134a LOW & HIGH Couplers, case, cover, ect

Is there others, you like.

1. Your dream manifold.
2. Budget friendly.
3. Middle of the road.

 

[flintknapper]

Likely, just glitch in listing software and/or who inputted.

The Yellow Jacket 49967. Doesn't come with anything, other than manifold and hoses. Like 134a LOW & HIGH Couplers, case, cover, ect

Is there others, you like.

1. Your dream manifold.
2. Budget friendly.
3. Middle of the road.

I'm pretty sold on the 49967 set. It is a good quality analog set with all the features you might need.

To go 'up' from there, you are talking the newer digital sets that can run well over $1K

A good manifold set with good hoses and a 'good' 2 stage vacuum pump is all a person needs to get started IF servicing vehicles for a living. The DIYer/home mechanic that works on systems infrequently can do with less of course.

Most sets don't include the High/Low side connectors....as there are different styles and folks like to choose their own. Don't scrimp there and create a weak link in your equipment.

Yellow Jacket 49967 Titan Charging Manifold 4-Valve w/ Sight Glass & 3-1/8 Gauges 4 Hoses

Shop Yellwo Jacket HVAC Tools. Number 49967. Titan Charging Manifold 4-Valve with Sight Glass and 3-1/8 Gauges 4 Hoses. McCombs Supply Co. Fast Shipping!

mccombssupply.com

 

[2001LC]

I'm pretty sold on the 49967 set. It is a good quality analog set with all the features you might need.

To go 'up' from there, you are talking the newer digital sets that can run well over $1K

A good manifold set with good hoses and a 'good' 2 stage vacuum pump is all a person needs to get started IF servicing vehicles for a living. The DIYer/home mechanic that works on systems in frequently can do with less of course.

Most sets don't include the High/Low side connectors....as there are different styles and folks like to choose their own. Don't scrimp there and create a weak link in your equipment.

Yellow Jacket 49967 Titan Charging Manifold 4-Valve w/ Sight Glass & 3-1/8 Gauges 4 Hoses

Shop Yellwo Jacket HVAC Tools. Number 49967. Titan Charging Manifold 4-Valve with Sight Glass and 3-1/8 Gauges 4 Hoses. McCombs Supply Co. Fast Shipping!

mccombssupply.com

Okay, thanks.
_________________

Different issues just came up. Not the one I'll be re vacuuming and charging tonight.

This is in a 06LC 226K. Owner said about 1 1/2 year ago. He DIY the HIGH pressure line coming off compressor over top of fan shroud. Due to leak, where rubber meets metal. He had some shop charge, for him. He didn't mention: Dyier, vacuuming or oil.

He said a few days ago, AC began working poorly.

I put my manifold on his system, and saw:
Off No PSI or Vacuum in low side. HIGH side 180PSI.
AC on MAX. LOW ~90PSI HIGH ~375PSI.
AC OFF: LOW 108PSI HIGH 355PSI.

Had to relieve pressure at manifold to get.

Any thoughts?

 

[2001LC]

I'd wager you have some air in the system. If you can find seals for your hose ends, just do that.
27 hg vacuum is probably pretty good (adjusted for altitude, which I don't know? 6,000 ft?).

Be sure to let your pump run long enough to boil off any moisture in the system ( a few hours). Also start with new vacuum pump oil if it has not been changed recently.

ALL R134a is the same (minimum standard) so the NAPA labled brand is fine. Pump the system back down really well. Be sure to close the valves on the manifold AND pump before shutting the pump down, so you don't get any air it the system.

As before, 'purge' the service line of air with each can of refrigerant (so no air gets in the system). A better vent temp thermometer would not be a bad thing.

Let's see if we can get those vent temps in the 45°F range (at idle, system stabilized) this go 'round.

So I did get to around 45F. After re vacuuming and charging. Used a new: yellow hose and 134a resealable can tap. At first I got the same (52F) then bought new thermostat and saw improvement. But still not 45F or less. Then I add 3 more oz of 134a. Tmep hot ~43F. Seems I was underfilling, by using 3 16oz 12 oz cans. Likely due to loss while bleeding air from H & L lines to manifold and bleeding yellow between can swaps..

Now that COLO requires reseal cans. I can easily stop and store partially used cans.

~45F actually saw it hit the green (~44F) at L35PSI H220PSI

 

[medtro]

Then I add 3 more oz of 134a. Tmep hot ~43F. Seems I was underfilling, by using 3 16oz cans. Likely due to loss while bleeding air from H & L lines to manifold and bleeding yellow between can swaps..

Seems a lot if you used 16oz cans. Overcharged will impact it's performance too.