Ideal low-side pressure for R-22 based ACs

[CivicFan1]

Hello Pakwheelers!

I wanted to know what the ideal psi reading on the lowside gauge should be for an R-22 charged 1.5 ton split AC, given the weather in Karachi when the sun's up; i.e. 38 degrees Celsius, around 40% humidity.

Is the optimal gas charge psi supposed to read 65 or 70 psi during the day after, say, an hour of operation? I had two splits recharged recently - the 1 ton AC indicates 70 psi, while the 1.5 ton AC shows 65 psi. The cooling performance of the 1 ton unit is pretty much consistent around the clock.

However, the 1.5 ton unit seems to not cool at peak efficiency once the ambient temperature cools down. So during the day, it performs like a champ, while the cooling capacity decreases by maybe 10% during/after sundown. So is it a no-brainer? Do I simply need to have it charged closer to 70 psi in order to get proper cooling in the evening/night as well?

[hassantahir2]

Hello Pakwheelers!

I wanted to know what the ideal psi reading on the lowside gauge should be for an R-22 charged 1.5 ton split AC, given the weather in Karachi when the sun's up; i.e. 38 degrees Celsius, around 40% humidity.

Is the optimal gas charge psi supposed to read 65 or 70 psi during the day after, say, an hour of operation? I had two splits recharged recently - the 1 ton AC indicates 70 psi, while the 1.5 ton AC shows 65 psi. The cooling performance of the 1 ton unit is pretty much consistent around the clock.

However, the 1.5 ton unit seems to not cool at peak efficiency once the ambient temperature cools down. So during the day, it performs like a champ, while the cooling capacity decreases by maybe 10% during/after sundown. So is it a no-brainer? Do I simply need to have it charged closer to 70 psi in order to get proper cooling in the evening/night as well?

Our 1 ton Haier AC with Toshiba compressor. Has almost 980 gram of gas written in its spec's. Last season when we recharged the gas (R22) in the unit the pressure reading was around 75 lower side...

In conditions 31 degree room temperature and 39 degree outside temperature with 18% humidity..

As we didn't charged gas by seeing pressures we charged the gas according to weight written on the unit....

But before that complete vacuum was pulled out of the system.

I think 1.5 ton AC must have the same readings. Can't accurately tell you about that..

Be-aware there are almost 3 types of gas available in market.. Which shop keepers refer to as and last year rates were something like this...

1: USA WALI.... 1100-/RS Per kg.
2: China wali.... 780-/RS Per kg.
3: Local.... 520-/RS Per kg.

Don't know there correct name's.. But they all have different effects on cooling of AC.

I myself now have purchased an old cylinder and get the gas from market myself and then give it to our AC Service man to fill in AC.

Otherwise these people usually have low quality gas with them and charge higher rates from the other person......

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[CivicFan1]

Our 1 ton Haier AC with Toshiba compressor. Has almost 980 gram of gas written in its spec's. Last season when we recharged the gas (R22) in the unit the pressure reading was around 75 lower side...

In conditions 31 degree room temperature and 39 degree outside temperature with 18% humidity..

As we didn't charged gas by seeing pressures we charged the gas according to weight written on the unit....

But before that complete vacuum was pulled out of the system.

I think 1.5 ton AC must have the same readings. Can't accurately tell you about that..

Be-aware there are almost 3 types of gas available in market.. Which shop keepers refer to as and last year rates were something like this...

1: USA WALI.... 1100-/RS Per kg.
2: China wali.... 780-/RS Per kg.
3: Local.... 520-/RS Per kg.

Don't know there correct name's.. But they all have different effects on cooling of AC.

I myself now have purchased an old cylinder and get the gas from market myself and then give it to our AC Service man to fill in AC.

Otherwise these people usually have low quality gas with them and charge higher rates from the other person......

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Thanks for the input though no AC tech here charges by weight. They don't know how to do it and will always go by pressure. I got mine done from the SG service technicians and their charges for gas refill are Rs. 3000.

75 psi sounds a bit high to me. It does not matter if it's 1, 1.5 or 2 ton - if it's a split that requires R-22, it needs to be around the 68-70 psi range, that's what I understand. Someone please correct me if I'm wrong.

It says my unit requires 1160g of R-22. I don't know what that equals to on the pressure gauge. I didn't get a vacuum done although I know that improves things quite a bit. Reason being a leak was detected and there was already 40 psi gas left, so he locked it off from the condenser side and proceeded to fix the leak. Saved me some cash.

I'm left with the conclusion that it needs to be higher than 65 psi and just under 70 or at 70 psi. That should improve cooling at night as well, as I imagine working in the 65 psi range during the day lowers the psi a bit at night, but that value falls below the "optimum operation range" so it doesn't cool as efficiently at night.

[hassantahir2]

Thanks for the input though no AC tech here charges by weight. They don't know how to do it and will always go by pressure. I got mine done from the SG service technicians and their charges for gas refill are Rs. 3000.

75 psi sounds a bit high to me. It does not matter if it's 1, 1.5 or 2 ton - if it's a split that requires R-22, it needs to be around the 68-70 psi range, that's what I understand. Someone please correct me if I'm wrong.

It says my unit requires 1160g of R-22. I don't know what that equals to on the pressure gauge. I didn't get a vacuum done although I know that improves things quite a bit. Reason being a leak was detected and there was already 40 psi gas left, so he locked it off from the condenser side and proceeded to fix the leak. Saved me some cash.

I'm left with the conclusion that it needs to be higher than 65 psi and just under 70 or at 70 psi. That should improve cooling at night as well, as I imagine working in the 65 psi range during the day lowers the psi a bit at night, but that value falls below the "optimum operation range" so it doesn't cool as efficiently at night.

They charge high in karachi for gas..

Here in my city usually AC technicians charge 1500-2000-/RS.

Don't know why but my AC always works good at this much pressure and i always use to get the gas charged by weight whenever needed. So i didn't bother for the pressures much.

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[CivicFan1]

The AC techs here are extremely stubborn and pig-headed; they think customers are completely unaware of how an air conditioner works. Anyway, no one charges my weight here, it's like Kyrptonite for them or something... ! lol

Hopefully, the guy will show up today and bring it closer to 70 psi. Let's see if that improves cooling across the board, particularly at night.

For the record, the unit has no leaks that I know of, but it does need a vacuum. AC tech inspected the evap and said it does not need cleaning yet.

[hassantahir2]

BOL.. With these idiots.

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[hassantahir2]

Actually i have also suffered from all this almost tried each and every person in my town all of them usually use to charge gas by pressure and vacuum by using some old compressor........ I was also fed up of all this..

After that i once visited my father's office and saw AC technicians there with proper equipment...
Usually they only work for the office but i talked to them settled the rates and said them that i will provide you the required Gas and you have to fill that gas after vacuuming the unit completely according to weight written on the unit and add some extra for extra feet of pipe attached. They agreed and after that day whenever there's something wrong with AC units i just call them and they come and sort that out..... And always fill my AC according to weight now after completely vacuuming the unit whenever there is some problem....

I have bid a farewell to town AC technicians from a long time after that.

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[CivicFan1]

Interesting!

Do you think you could extend their contact details to me? I'd sure appreciate that.

[SER_GTR]

They Simply Make Low Side 65 And Done...And Forget The Fact That 65 Can Remain Same While High Side Can Vary...Its Not How Its Done By Pressure Method...Pressure Varies As Per Temp Also.....Its Abt Charging System Till It Reach It Point Of Maxx Effeciency Which Is Determined By Charging Via Superheat/Sub-Cooling Method

If You Have Company Line set and Wanna Charge By Weight Then Use Weight Scale....Evacuating Is Equally Important As Charging Right Amount Of Gas...Without All These Its Just Hit And CHeck....Will Make You Run In Circles Wondering What Went Wrong

[hassantahir2]

Interesting!

Do you think you could extend their contact details to me? I'd sure appreciate that.

Sorry as you are in sindh, karachi......
And i am in punjab, Faisalabad....
So you wouldn't b able to contact them...

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[CivicFan1]

They Simply Make Low Side 65 And Done...And Forget The Fact That 65 Can Remain Same While High Side Can Vary...Its Not How Its Done By Pressure Method...Pressure Varies As Per Temp Also.....Its Abt Charging System Till It Reach It Point Of Maxx Effeciency Which Is Determined By Charging Via Superheat/Sub-Cooling Method

If You Have Company Line set and Wanna Charge By Weight Then Use Weight Scale....Evacuating Is Equally Important As Charging Right Amount Of Gas...Without All These Its Just Hit And CHeck....Will Make You Run In Circles Wondering What Went Wrong

Unfortunately, that is not an option.. not just for me, but for anyone having to call AC techs to look at their AC. You know how people in our country are generally stubborn and hesitant to learn new things? "Ustad nay aisay sikhaya, bus siraf yay tureeka sahi hay!"

I will have to live with this - hope I can make it through summers in one piece. I had it charged up to almost 70 psi - however, it was partially cloudy at the time and I may have overcharged it. Cooling has remained the same, in fact, now it is having a harder time trying to lower the room temp to even 25 deg C at night. I may have to let out a little gas, but its difficult to know how much I'm letting out if I press a screw driver against the suction valve for a second or two.

How long would I have to press down on the valve to let out, say, 2-3 psi gas?

I have no choice right now but to experiment a little as I'm out of funds now trying to get my unit to work at peak capacity for over 2 months now.

Will have to wait till next year for a full flush for leak-testing, along with vacuum and gas recharge. That is, if it doesn't leak. I hope it doesn't. Got a really bad taste in my mouth... the kind of taste that says that it's about to leak again or already has.

Probably won't be calling on the so-called SG service guys to look at it again. If you know anyone at all in Khi who can recommend a reliable, trust-worthy guy, do share details.

Thanks!

[SER_GTR]

Unfortunately, that is not an option.. not just for me, but for anyone having to call AC techs to look at their AC. You know how people in our country are generally stubborn and hesitant to learn new things? "Ustad nay aisay sikhaya, bus siraf yay tureeka sahi hay!"

I will have to live with this - hope I can make it through summers in one piece. I had it charged up to almost 70 psi - however, it was partially cloudy at the time and I may have overcharged it. Cooling has remained the same, in fact, now it is having a harder time trying to lower the room temp to even 25 deg C at night. I may have to let out a little gas, but its difficult to know how much I'm letting out if I press a screw driver against the suction valve for a second or two.

How long would I have to press down on the valve to let out, say, 2-3 psi gas?

I have no choice right now but to experiment a little as I'm out of funds now trying to get my unit to work at peak capacity for over 2 months now.

Will have to wait till next year for a full flush for leak-testing, along with vacuum and gas recharge. That is, if it doesn't leak. I hope it doesn't. Got a really bad taste in my mouth... the kind of taste that says that it's about to leak again or already has.

Probably won't be calling on the so-called SG service guys to look at it again. If you know anyone at all in Khi who can recommend a reliable, trust-worthy guy, do share details.

Thanks!

Trust Me Don't Take R22 Refrigerant For Granted...It Can Give You BURN....Yes ...FREON Burn...Frostbite...Be Careful Dealing With It And Its Not Tyre Air Valve You Press And Get It Out....You Need To Be Careful Handling It....It Can Be Very Dangerous For Your Eyes As Well As Hand ...Can Give You BURN... Always Wear Safety Glasses And Gloves While Trying Such Stuff....

Proper Way Is To Use Recovery Machine Or Release It After Connecting Refrigerant Gauge.. Slowly And Checking On Gauge .....DO NOT Press The Valve With Bare Hands With UNIT Close Or Running... A High Pressure In System Out In Atmosphere Can Instantly Give You Frostbite......

[CivicFan1]

Trust Me Don't Take R22 Refrigerant For Granted...It Can Give You BURN....Yes ...FREON Burn...Frostbite...Be Careful Dealing With It And Its Not Tyre Air Valve You Press And Get It Out....You Need To Be Careful Handling It....It Can Be Very Dangerous For Your Eyes As Well As Hand ...Can Give You BURN... Always Wear Safety Glasses And Gloves While Trying Such Stuff....

Proper Way Is To Use Recovery Machine Or Release It After Connecting Refrigerant Gauge.. Slowly And Checking On Gauge .....DO NOT Press The Valve With Bare Hands With UNIT Close Or Running... A High Pressure In System Out In Atmosphere Can Instantly Give You Frostbite......

Good looking out!

But I have done this before - I used a regular screwdriver to press on the valve until it released gas. Just had to wipe the screwdriver off as there were greasy, light green-colored remains on it, probably a mix of refrigerant and compressor oil.

I'm thinking of buying a gauge first to make sure I don't let out too much gas, but can you really tell how much you're letting out after holding it for 1, maybe 2 seconds?

Is it better to release gas with the system on or off? With the unit off, I guess it would release too much gas.

[SER_GTR]

Good looking out!

But I have done this before - I used a regular screwdriver to press on the valve until it released gas. Just had to wipe the screwdriver off as there were greasy, light green-colored remains on it, probably a mix of refrigerant and compressor oil.

I'm thinking of buying a gauge first to make sure I don't let out too much gas, but can you really tell how much you're letting out after holding it for 1, maybe 2 seconds?

Is it better to release gas with the system on or off? With the unit off, I guess it would release too much gas.

Invest On Gauge And I Say Vacuum Pump Too....A K-Type Line Thermometer....And 2 Mercury Type Which Can Read Ambient......

After That You Will Be Good To Go On Your Own

Regarding Leaking Of Shreeder Valve So Yes Thats Refrigerant That Is Oily But It Also Gets Frosted When You Run System And Trying To Adjust Pressure...So Be Very Careful Abt That...And Always Wear Eye Safety Glasses And But Pair Of Gloves To Be Safe...

And Do No Mess With Shrader Valve Too Much...If It Develop Leak...It Will Leak Refrigerant From There Slowly So Also Be Very Gentle On It

[CivicFan1]

Invest On Gauge And I Say Vacuum Pump Too....A K-Type Line Thermometer....And 2 Mercury Type Which Can Read Ambient......

After That You Will Be Good To Go On Your Own

Regarding Leaking Of Shreeder Valve So Yes Thats Refrigerant That Is Oily But It Also Gets Frosted When You Run System And Trying To Adjust Pressure...So Be Very Careful Abt That...And Always Wear Eye Safety Glasses And But Pair Of Gloves To Be Safe...

And Do No Mess With Shrader Valve Too Much...If It Develop Leak...It Will Leak Refrigerant From There Slowly So Also Be Very Gentle On It

Sounds like an expensive investment...

The Shrader valve can develop leaks just by pressing it to release gas?

Well, I did wear a glove. And I was quite gentle - used a screwdriver tip to gently let it out in two quick bursts. That's it. Has the cooling improved? Maybe. Can't say. But I sincerely hope it isn't leaking gas again.

[SER_GTR]

Sounds like an expensive investment...

The Shrader valve can develop leaks just by pressing it to release gas?

Well, I did wear a glove. And I was quite gentle - used a screwdriver tip to gently let it out in two quick bursts. That's it. Has the cooling improved? Maybe. Can't say. But I sincerely hope it isn't leaking gas again.

Yes They Go Bad And Can Leak....Those 2 Gentle Push Might Not Harm But Servicing Like Again And Fixing Leaks And Check And Connecting Gauge Again And Again Will Make It Go Leak With Time...

Its Simple ...Either Invest Once And Get Over It Or Keep Beating The Bush And Let Those TAKNESSAN Do What Thet Like And Dont Complain ....

[CivicFan1]

Yes They Go Bad And Can Leak....Those 2 Gentle Push Might Not Harm But Servicing Like Again And Fixing Leaks And Check And Connecting Gauge Again And Again Will Make It Go Leak With Time...

Its Simple ...Either Invest Once And Get Over It Or Keep Beating The Bush And Let Those TAKNESSAN Do What Thet Like And Dont Complain ....

"Taknessan".. hahah!

Good advice. Much appreciated. :tup:

You've been performing maintenance on your ACs yourself all along?

Edit: I do hear a very mild whistling sound coming from the AC when it is running. Very faint sound though, hardly audible. Is that a sign there is gas slowly leaking or excessive air + moisture in the system perhaps?

[SER_GTR]

[QUOTE=CivicFan1;5081820] "Taknessan".. hahah!

Good advice. Much appreciated. :tup:

You've been performing maintenance on your ACs yourself all along?

Edit: I do hear a very mild whistling sound coming from the AC when it is running. Very faint sound though, hardly audible. Is that a sign there is gas slowly leaking or excessive air + moisture in the system perhaps? [/QUOTE

Yes I Do It Myself...And Adding Up On Equipment Timely... Recently Installed One Unit Myself

That Sound Is Possibly The Refrigerant Flowing Into Evaporator And It Do Comes But Get Away.....Leak In System Can Be Easily Caught By Checking Oil On Lines ....Leak Will Leave Its Oil Trace And A Big Leak Will Make It Easy....Zero Gas In No Time As System Is Pressurized.....If You Suspect Leak...Check The Flare Connections...

[SER_GTR]

"Taknessan".. hahah!

Good advice. Much appreciated. :tup:

You've been performing maintenance on your ACs yourself all along?

Edit: I do hear a very mild whistling sound coming from the AC when it is running. Very faint sound though, hardly audible. Is that a sign there is gas slowly leaking or excessive air + moisture in the system perhaps?

Yes I Do It Myself...And Adding Up On Equipment Timely... Recently Installed One Unit Myself

That Sound Is Possibly The Refrigerant Flowing Into Evaporator And It Do Comes But Get Away.....Leak In System Can Be Easily Caught By Checking Oil On Lines ....Leak Will Leave Its Oil Trace And A Big Leak Will Make It Easy....Zero Gas In No Time As System Is Pressurized.....If You Suspect Leak...Check The Flare Connections...

[CivicFan1]

Yes I Do It Myself...And Adding Up On Equipment Timely... Recently Installed One Unit Myself

That Sound Is Possibly The Refrigerant Flowing Into Evaporator And It Do Comes But Get Away.....Leak In System Can Be Easily Caught By Checking Oil On Lines ....Leak Will Leave Its Oil Trace And A Big Leak Will Make It Easy....Zero Gas In No Time As System Is Pressurized.....If You Suspect Leak...Check The Flare Connections...

There are no traces of oil on the lines - I checked all the flare connections/valves with soapy water + foam. No bubbles there. Didn't check the lines on the other side of the condenser which are going into my room as that would require a tall ladder.

Since releasing the gas in two quick bursts last night, I have not noticed any difference in cooling performance.

The "air throw" is just not as strong as it should be. Neither is the air coming out from the vent ice-cold. It is reasonably cold. Takes a while to suck warm air and humidity from the room. My car AC on the other hand is a champ though - I step out of it and my shades fog up right away, whether its day or night. Aren't 1.5 split ACs supposed to have the same cooling efficiency? My room should feel cold and dry when I enter it , compared to the hall for example, which is warm and humid. But it doesn't. The temperature difference is not there.

Clogged lines or evaporator?

I know this is a silly thing to ask, but I will take my chances: are you willing to leak-test, vacuum and charge my AC?