air conditioner

dougrainer wrote:

joe0508 wrote:

kaydeejay wrote:

joe0508 wrote:

dougrainer wrote:
OK, HOW much 134a are you putting IN:h Doug

I assume the gauge will tell according to ambiant temperature.

If the kit is worth buying it will give you a pressure to aim for depending on ambient temps - yes.
If you have lost refrigerant, then you must have a (slow) leak.
You might want to find a can of R134A with leak sealer included.
No guarantees, (won't fix compressor seals) but it might help.

I have found some leak sealer that is supposed to work on metal lines as well as rubber lines it is called ac pro super seal your supposed to use it before charging it with ac pro refrigerate.

Yes, the Pro Super seal does work on small leaks. I do NOT know how it will work on a Converted system(12 to 134a). Your Gauge will NOT give you accurate pressure for a full charge. Even attempting to temp correct it. The Cheap(sorry, inexpensive) gauges have a large error factor on the needle read out. You REALLY need a Hi and Low side readout to charge. Better yet is to charge with the exact charge for your particular system. But, that is difficult to find unless the original charge sticker is still on or readable on your RV. Remember, TOO LITTLE 134a and it will not cool adequately. TOO MUCH and it also will not cool adequately and will produce extreme hi pressures. Just take it slow and watch your output temp on the outlet closest to the blower/evaporator. Run the engine at least 1200 RPM while charging. Make sure you have it on MAX or Recirc on the Dash control. A way to tell is to have a digital thermometer in that outlet and have someone inside reading out the temp drop. When you reach saturation, the output temp will start to rise. ONCE THAT HAPPENS, stop the charge. You are as close as you can get with your tools. Doug

Also, when charging under all of the conditions Doug listed, watching the suction line can be a good visual indicator. It should sweat back to the compressor. If any part of the compressor body is sweating then you are likely overcharged.R-134a is a pretty forgiving refrigerant and it is stable enough to let you do that. On some of the other blends that run high pressures or have unstable head pressures, it's a different matter, but none of those are used in automotive equipment. There is no one indicator that you can use alone to determine if the charge is right. A/C is not rocket science, but if you are not familiar with all of the indicators and what they mean. you are probably ahead paying a shop to do it. If you have lost the charge to the point of needing to add freon, you probably also have a leak that needs to be fixed anyway.

Having sold and serviced marine air conditioning and refrigeration for 15 years, I can tell you without doubt that the suction side line is ALWAYS bigger. No exceptions.

Well yes, but I do not like making statements like that, Hence the use of the word "OFTEN".. (If there is an exception.. I've not seen it,, but I like to leave the possibility open)

wa8yxm wrote:


Also, if you look at the pipe the fitting is attached to.. OFTEN the low pressure pipe is much larger than the high pressure pipe.

The line on the suction side is ALWAYS larger than the discharge side.

joe0508 wrote:

kaydeejay wrote:

joe0508 wrote:

dougrainer wrote:
OK, HOW much 134a are you putting IN:h Doug

I assume the gauge will tell according to ambiant temperature.

If the kit is worth buying it will give you a pressure to aim for depending on ambient temps - yes.
If you have lost refrigerant, then you must have a (slow) leak.
You might want to find a can of R134A with leak sealer included.
No guarantees, (won't fix compressor seals) but it might help.

I have found some leak sealer that is supposed to work on metal lines as well as rubber lines it is called ac pro super seal your supposed to use it before charging it with ac pro refrigerate.

Yes, the Pro Super seal does work on small leaks. I do NOT know how it will work on a Converted system(12 to 134a). Your Gauge will NOT give you accurate pressure for a full charge. Even attempting to temp correct it. The Cheap(sorry, inexpensive) gauges have a large error factor on the needle read out. You REALLY need a Hi and Low side readout to charge. Better yet is to charge with the exact charge for your particular system. But, that is difficult to find unless the original charge sticker is still on or readable on your RV. Remember, TOO LITTLE 134a and it will not cool adequately. TOO MUCH and it also will not cool adequately and will produce extreme hi pressures. Just take it slow and watch your output temp on the outlet closest to the blower/evaporator. Run the engine at least 1200 RPM while charging. Make sure you have it on MAX or Recirc on the Dash control. A way to tell is to have a digital thermometer in that outlet and have someone inside reading out the temp drop. When you reach saturation, the output temp will start to rise. ONCE THAT HAPPENS, stop the charge. You are as close as you can get with your tools. Doug

As I recall the fittings for 134 are different sizes.. I see someone up-thread confirmed this.. (Thanks).

Also, if you look at the pipe the fitting is attached to.. OFTEN the low pressure pipe is much larger than the high pressure pipe.

IF the unit is running the high pressure pipe will be HOT and the low pressure pipe NOT if it's working at all.

kaydeejay wrote:

joe0508 wrote:

dougrainer wrote:
OK, HOW much 134a are you putting IN:h Doug

I assume the gauge will tell according to ambiant temperature.

If the kit is worth buying it will give you a pressure to aim for depending on ambient temps - yes.
If you have lost refrigerant, then you must have a (slow) leak.
You might want to find a can of R134A with leak sealer included.
No guarantees, (won't fix compressor seals) but it might help.

I have found some leak sealer that is supposed to work on metal lines as well as rubber lines it is called ac pro super seal your supposed to use it before charging it with ac pro refrigerate.

Do you mean the dash A/C ?

joe0508 wrote:

dougrainer wrote:
OK, HOW much 134a are you putting IN:h Doug

I assume the gauge will tell according to ambiant temperature.

If the kit is worth buying it will give you a pressure to aim for depending on ambient temps - yes.
If you have lost refrigerant, then you must have a (slow) leak.
You might want to find a can of R134A with leak sealer included.
No guarantees, (won't fix compressor seals) but it might help.

dougrainer wrote:
OK, HOW much 134a are you putting IN:h Doug

I assume the gauge will tell according to abiant temperature.