Fwd: [Chrysler300] 300 G A/C

If too much liquid , it can fill compressor head space and generate extreme pressure which will ruin compressor reed valves , burst hoses or blow off the hi pressure relief valve most systems have . Some newer have electric shut off . But some have nothing as it cannot ever be overcharged if done per FSM , which is weighing the charge . Remember what goes into compressor is cold low pressure gas , what comes out is hot high pressure gas. No liquid ever in compressor cylinder . Liquid happens later in the condenser, when air flow removes heat , soon cooler gas near exit pipe turns back to liquid and ends up in receiver / dryer . This warm liquid under high pressure then goes to expansion valve , as it turns to gas it absorbs heat at evaporator. Like boiling water absorbs heat from gas flame . And vapor leaves pot. Same thing. All this requires a close to correct fill . There is some margin with what is stored in dryer as a liquid for very slow leaks . Maybe a cup extra . Why it will run a few months despite a leak with a can added . But if it is working adding more is risky . On many of our cars there is a sight glass . If you see obvious bubbles there going into dryer , it needs more . Until bubbles go away . Now it is all liquid .into receiver . All you know . Adding more will not make it colder. .

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On Aug 24, 2017, at 8:17 PM, EMills_ATC <millserat@xxxxxxxxxxxxx> wrote:

Overcharge = disaster - can you explain symptoms of that

Edward Mills Antique Tractors 1930-1960 Antique Cars 1960-1985

On 8/24/2017 5:34 PM, John Grady jkg@xxxxxxxxxxxxxxxxx [Chrysler300] wrote:

Just quickly, pressure readings do not tell you charge level, but I agree throwing in one can like that --if you know for sure low can fix it. If it is not low you can overcharge , = disaster . The only way to correctly charge is by weight of refrigerant and a scale -which they do in an empty system or first pull out what is in there with suction AC machine ( a law now) . Excess liquid refrigerant is kept in the car receiver / dryer tank , by design .

It is like a propane tank . Pressure is the same almost empty or full . Pressure is Set only by temp of propane ,or refrigerant not by how much is in tank .. for things that are liquid at room temp under pressure , but change to gas if pressure drops . Why gas comes out in your grill , not liquid . And flame stays about the same size ( same pressure) as the liquid tank empties on a hand held propane torch . And gets cold. Straight compressed gas ( oxygen) non liquified yes pressure tells you % full in cu ft .

Somewhere in FSM is weight in oz of new charge .. about 2 cans + usually. By way of understanding , not critique .

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On Aug 24, 2017, at 5:08 PM, Ray Jones 1970hurst@xxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

Go to Walmart*, there you will find a 134-A refill kit.

It consists of a can of 134*A, a gauge, hose and handle.

Hook it up to your system, Will only attach to one connector.

Follow directions (Nobody will see you doing it)
What you want to do is watch the gauge and see what the pressure is while it's running.

If it's low, pull the trigger and add Freon until it gets the pressure up to the range it wants.

The gauge has the ranges marked on it, so it's easy.

When finished, but the rig in you tool box for future use, you can add more bottles when you need them, I get them on sale @ $3.85 or less @ Atwoods.

If you have a 2 gauge pro system, look for the pressure to be 1/2 ambient air temp on the low side and double or more on the high side. Some charts I just looked at are showing pressure to be triple ambient air temp.
And of course you add Freon thru the gauges.

On Thu, Aug 24, 2017 at 3:44 PM, 'Rich Barber' c300@xxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

My understanding is that R-134 refrigerant has different thermodynamic properties and expands to a somewhat higher temperature than does R-12 from a given pressure. Newer cars adjust for that with larger evaporator coils and flow rates to achieve cooling but the outlet air temperature will never be 40F again. The capillary expansion tube is no-doubt different, also. Our ’99 Wrangler FA/C starts cooling immediately. Our ’05 Durango starts cooling slowly but eventually gets the job done. Both use R-134.

No doubt, R-12 was a great refrigerant for cars. Eventually, nearly all refrigerants will be vented to atmosphere. Some may be broken down but the chlorine will still go to the atmosphere and break down the ozone (O3) layer (or so they say). Changeover was on or about 1-1-94.

Rich Barber, BSME

Brentwood CA

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@yahoogroups.com] On Behalf Of Val Jeffers edward1108@xxxxxxxxx [Chrysler300]
Sent: Thursday, August 24, 2017 10:38 AM
To: Chrysler 300 List <chrysler300@xxxxxxxxxxxxxxx>
Subject: [Chrysler300] 300 G A/C

Greetings,

               The service manual states 45 ounces of R12 Freon is the capacity. My question is, since converting to R134 several years ago, is that still the correct number ? I think mine is running low and want to recharge as it is blowing cool but not cold as it should be.

                                                                                Thanks,

                                                                                Val Jeffers



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