Lowest temp you can charge A/C?

[LvR]

Watch this video - in particular around 1:56 and realize that this is what most every AC shop is doing rather than emptying and recharging by weight if the AC system is just low on gas.



Again - how do YOU know that system of yours is low on gas if you have such an aversion to using gauges and P/T charts and the known ambient temperature? - IOW why do YOU want to add refrigerant NOW?

 

[atikovi]

I do not know what you are reading in that case.

Numerous sources but you can go straight to the EPA website if you don't believe me: https://www.epa.gov/mvac/options-recharging-your-air-conditioner

Topping off Versus Evacuation and Recharge​

A top off involves adding refrigerant to your MVAC. There is no way for technicians to determine how much refrigerant is in your MVAC system when you arrive at the shop, so they must guess how much refrigerant to charge into the system. They may undercharge or overcharge the system—both of which impair system performance.

 

[atikovi]

Watch this video - in particular around 1:56 and realize that this is what most every AC shop is doing rather than emptying and recharging by weight if the AC system is just low on gas.



Again - how do YOU know that system of yours is low on gas if you have such an aversion to using gauges and P/T charts and the known ambient temperature? - IOW why do YOU want to add refrigerant NOW?

Yea like I'm going trust some DIY mechanic with a youtube channel over an established organization.

 

[LvR]

Numerous sources but you can go straight to the EPA website if you don't believe me: https://www.epa.gov/mvac/options-recharging-your-air-conditioner

Topping off Versus Evacuation and Recharge​

A top off involves adding refrigerant to your MVAC. There is no way for technicians to determine how much refrigerant is in your MVAC system when you arrive at the shop, so they must guess how much refrigerant to charge into the system. They may undercharge or overcharge the system—both of which impair system performance.

If the system is running there is already enough refrigerant in the system to prevent the compressor protection from operating - iow its safe for the compressor to run by definition of the engineers that designed the system. Now whether or not you want to believe it - the P/T chart and gauges is the governing mechanism of ANY and ALL AC systems - and the exact weight is completely irrelevant once you realize the P/T chart governs the weight

I am out, I give up - its obvious you have no intention to solve a really simple problem that we already said can be solved in one of 2 ways:

You either evacuate and fill by weight, or you just top off using a well-established industry technique that is least wasteful and cumbersome as well as fast.

Though .................. still no answer on WHY you are of the opinion it needs recharging at all

 

[atikovi]

You either evacuate and fill by weight, or you just top off using a well-established industry technique that is least wasteful and cumbersome as well as fast.

Though .................. still no answer on WHY you are of the opinion it needs recharging at all

What well-established industry technique? By DIY'ers? What I posted comes straight from the EPA that regulates much of the industry. Paging Chris142.

Why? because the car was sitting 6 years so seals tend to shrink from lack of lubrication and freon can slowly leak out and drop the level below optimum capacity. The gauges were reading 10/50 psi around 45° which seems quite low. For less than $5 of freon and 2 hours time, mostly vacuuming, it's good to know the system is ready to go.

 

[LvR]

What well-established industry technique? By DIY'ers? What I posted comes straight from the EPA that regulates much of the industry. Paging Chris142.

Why? because the car was sitting 6 years so seals tend to shrink from lack of lubrication and freon can slowly leak out and drop the level below optimum capacity. The gauges were reading 10/50 psi around 45° which seems quite low. For less than $5 of freon and 2 hours time, mostly vacuuming, it's good to know the system is ready to go.

So it's ok to use a gauge to only figure its low on refrigerant, yet I don't know what I am talking about when I suggest you use that same gauge to "top-off" the system (iow replace JUST the missing/leaked part) so that the gauges no longer "seems low".

For less than $5 of freon and 2 hours time, mostly vacuuming, it's good to know the system is ready to go.

If you use the gauge and P/T chart method I suggested on the already running system, you could cut that down to probably $2 and 15 minutes if not less without the need for vacuuming

If however you like to insist on only making use of "professionals" (that in your opinion can quote EPA rules and are quite comfortable using ONLY a weight based recharge tool but have no understanding of the system's engineering at all) .................. then go ahead - why even start this thread then?

Since you apparently have a love affair with @Chris142 and his opinions, here is hoping he will indeed chime in to educate me too

 

[Jetronic]

What well-established industry technique? By DIY'ers? What I posted comes straight from the EPA that regulates much of the industry. Paging Chris142.

Why? because the car was sitting 6 years so seals tend to shrink from lack of lubrication and freon can slowly leak out and drop the level below optimum capacity. The gauges were reading 10/50 psi around 45° which seems quite low. For less than $5 of freon and 2 hours time, mostly vacuuming, it's good to know the system is ready to go.

I worked on busses and coaches. AC content was often not available. I went by pressures even though I always started with a vacuumed system (usually had a leak that I fixed before).

 

[Chris142]

It's pretty tough to recharge a system in cold temps with a guage. Even with a pressure and temp chart you will likely overcharge it.Seen it many times. On the first warm day it will hit the high pressure switch or blow it out the relief valve.

You are better going with feeling the low side line. When it gets ice cold stop.

 

[Chris142]

Watch this video - in particular around 1:56 and realize that this is what most every AC shop is doing rather than emptying and recharging by weight if the AC system is just low on gas.



Again - how do YOU know that system of yours is low on gas if you have such an aversion to using gauges and P/T charts and the known ambient temperature? - IOW why do YOU want to add refrigerant NOW?

I don't know of any shops in my area that use a can and guages. All do a proper evac and charge with a RRR machine.

 

[EA82]

$380 plus tax for a 30 lbs jug at the supply house, I remember Sam's club had them for around $70 a few years ago.

 

[atikovi]

$380 plus tax for a 30 lbs jug at the supply house, I remember Sam's club had them for around $70 a few years ago.

Is this a temporary thing? One of my dealers said $299 on Friday but I have enough for probably the rest of the year.

 

[Chris142]

Is this a temporary thing? One of my dealers said $299 on Friday but I have enough for probably the rest of the year.

Part of the massive inflation we are seeing. I got quoted $400 for a 30# r134a today

 

[EA82]

Is this a temporary thing? One of my dealers said $299 on Friday but I have enough for probably the rest of the year.

Not sure if it is temporary, I was reading it is a combination of short supply because of covid (r410a has skyrocketed also) and r134a being phased out, I'm gonna wait until I need it and hope the price drops.

 

[Jetronic]

I vacuumed my own car AC 7 years ago when it was only 2 years old. I could hear a slight hiss from the evaporator indicating a low charge. 50% of the nominal fill was gone, or the car was undercharged from the factory.

I added a bit of POE 100 oil to the system and filled to the proper weight. 7 years on, still good. I hope it's gonna last 7 more with those prices, don't have access to AC equipment anymore.