Recharing 2009 Mazda5 - the service manual or normal way?

[mzr]

I am attempting to recharge my 2009 Mazda5. I have vacuumed the system for an hour and a half, let it sit under vacuum multiple days. It has held vacuum, and I am charging by weight with 12 ounce cans and a scale. I can get it to take about three ounces of refrigerant, and the low side goes up to about 120-125psi and so does the high side. The compressor does not come on.

Thinking that this wasn't right, I looked up what the service manual has to say about it, and it states to fill through high side with the engine off until you have 14psi on the low side, close the valves and check for leaks. Then keep charging until you get 8.83 ounces into the system, close the valves, start the engine and charge the rest through the low side.

The reason given for this by the manual: Always begin charging of refrigerant from the high-pressure side. If charging is started from the low-pressure side, the vanes of the A/C compressor will not be released and abnormal noise may result.

I've never dealt with what I assume is a variable displacement compressor, should I redo the recharge with the service manual procedure, or is something else possible wrong? It has all original A/C system parts, I have owned it since new and have not replaced anything in the system.

[JohnHere]

I am attempting to recharge my 2009 Mazda5. I have vacuumed the system for an hour and a half, let it sit under vacuum multiple days. It has held vacuum, and I am charging by weight with 12 ounce cans and a scale. I can get it to take about three ounces of refrigerant, and the low side goes up to about 120-125psi and so does the high side. The compressor does not come on.

It sounds like your Manifold Gauge Set isn't "communicating" with the system and is reading only the pressure in one of the cans. So looking at the simple things first, are you sure that the service port adapter on the low side is fully open as you're attempting to charge the system? The thumbwheel at the end of the blue and red hoses should be turned fully clockwise to the open position, and the handwheel on your MGS, low side only, should be turned fully counter-clockwise to open it. The handwheel on the high side of your MGS should remain closed, or turned fully clockwise.

Thinking that this wasn't right, I looked up what the service manual has to say about it, and it states to fill through high side with the engine off until you have 14psi on the low side, close the valves and check for leaks. Then keep charging until you get 8.83 ounces into the system, close the valves, start the engine and charge the rest through the low side.
The reason given for this by the manual: Always begin charging of refrigerant from the high-pressure side. If charging is started from the low-pressure side, the vanes of the A/C compressor will not be released and abnormal noise may result.

Charging through the high side is very tricky and can be exceedingly dangerous for those who aren't thoroughly experienced and well-versed in the process. That's why I recommend charging only through the low side, by weight, as you plan to do.

That said, I never heard of the vanes of the compressor not being "released," resulting in abnormal noise. I'm unsure as to the meaning of that sentence.

I've never dealt with what I assume is a variable displacement compressor, should I redo the recharge with the service manual procedure, or is something else possible wrong? It has all original A/C system parts, I have owned it since new and have not replaced anything in the system.

I believe the OE for your car is a fixed-displacement rotary vane compressor with an overheat switch, not a variable displacement compressor with a control valve. IMHO, you should be able to charge this system from the low side only into a well-held vacuum, and you should have no problems doing so unless something else is wrong.

[mzr]

It sounds like your Manifold Gauge Set isn't "communicating" with the system and is reading only the pressure in one of the cans. So looking at the simple things first, are you sure that the service port adapter on the low side is fully open as you're attempting to charge the system? The thumbwheel at the end of the blue and red hoses should be turned fully clockwise to the open position, and the handwheel on your MGS, low side only, should be turned fully counter-clockwise to open it. The handwheel on the high side of your MGS should remain closed, or turned fully clockwise.

That is what I'm starting to think, and this is the first time dealing with self-sealing cans. I bought a brass can tap for the self-sealer cans. I have checked the thumb wheels on both high and low side, and they are fully open. They are marked with the direction to open them, and I get a good vacuum reading on both sides when pulling vacuum. Something odd about this particular gauge set is the charge hose is a 1/4" fitting at the can end. I have to use an adapter on the can tap, maybe it is pulling air past the threads on the adapter. I have filled two other cars with this gauge set and can tap with adapter, but they were the older piercing top cans.

I do have another gauge set but the hoses are cracked from age. I am ordering a new hose set to see if it will work with the car better than the one I am using now.

Charging through the high side is very tricky and can be exceedingly dangerous for those who aren't thoroughly experienced and well-versed in the process. That's why I recommend charging only through the low side, by weight, as you plan to do.

That said, I never heard of the vanes of the compressor not being "released," resulting in abnormal noise. I'm unsure as to the meaning of that sentence.

It isn't very clear, but it is from the factory Mazda service manual. I tried the procedure in the service manual. I filled through the high side with the engine off. It hit 14psi on the low side very quickly, and I closed the high side hand wheel to check for leaks. None found, and I opened the high side hand wheel back up and it put three ounces in, and the pressure on both the low and high side reaches 110-115psi. I was wrong about the pressure before, it was 110 not 125. It seems to hit a wall after the three ounces and 110psi. Closing the high side hand wheel and starting the engine and then opening the low side hand wheel, it does not take anymore refrigerant and the compressor still does not engage.

I believe the OE for your car is a fixed-displacement rotary vane compressor with an overheat switch, not a variable displacement compressor with a control valve. IMHO, you should be able to charge this system from the low side only into a well-held vacuum, and you should have no problems doing so unless something else is wrong.

I thought it was a variable displacement due to seeing recommendations to replace it with a piston-type compressor. I did not know about rotary vane compressors. Thank you.

I'm going to wait on the new manifold hoses and then try again. I know the compressor is not locked up and did engage and cycle before I evacuated the refrigerant. I will check the wiring and clutch just to make sure.

[JohnHere]

The self-sealing can tap that you have and/or the can itself might be defective. Try a side can tap, available from this Forum's sponsor, that actually pierces the side of the can. The self-sealing cans are beginning to develop a reputation for being trouble-prone.

[mzr]

The self-sealing can tap that you have and/or the can itself might be defective. Try a side can tap, available from this Forum's sponsor, that actually pierces the side of the can. The self-sealing cans are beginning to develop a reputation for being trouble-prone.

I went out and got a new gauge set and can tap. I got it to take 12 ounces but it was a fight. The compressor finally engaged during filling and it drew the low side into a vacuum. Don't really remember what the high side did, I think it didn't do much and it was at about 120psi.

I have a expansion valve, o-ring kit, and drier I purchased a few years ago and I am going to install those as I already have them. I've already pulled the expansion valve. I think I see the spring that holds the pin closed is weak as it doesn't seem to be all the way down and you can see the end of the pin. The orifice is three-quarters open.

I do have a side can tap, I've not been able to get it to flow any refrigerant. I think I've solved it. The charge hose from the prior gauge set didn't have a foot to open the Schrader valve on the nipple of the tap. The new gauge set hoses I have now works.

[tbirdtbird]

You always have to check your hoses and see what’s up with the depresosrs