A/C recharge kits

[harry kew]

I went in to check out the a/c recharge kits and they told me if I use a do-it-yourself kit that an a/c shop won't work on it after that or will charge you a lot more money to clean the system out.
They said that it was the dyes that will plug up their machine and it was expensive to have it cleaned.
Has anyone run into this or am I getting led astray?

[Gerald Farris]

Harry,
First, everything that you just posted is incorrect. Automotive A/C shops commonly inject dye into a system to locate a leak. The dye does not harm their equipment, in fact every charging station that I have ever seen had some dye in it. The refrigerants that contain a stop leak may be a different issue, but I do not think that it will be. Regardless, there is no way for a commercial to know about the stop leak unless you tell them. If it goes through your expansion valve, it will go through an A/C charging station.  

Second, there is no reason to use a refrigerant that contains dye unless you are going to try to locate a leak with a black light. The straight R134A refrigerant is all that you need to top off the system charge level. Using a refrigerant that contains extra oil or dye is just a waste of money.

Gerald

[Orman Claxton]

Hi Everyone
let me jump in for a few words.
I spent my entire working life in the  refrigeration industry,
If you have a refrigerant leak, you are wasting money charging your AC system yourself.
Someone has to locate the leak, make repairs or maybe it is not low coolant, maybe it is a drier, expansion valve.
Only someone who knows what they are doing can make the proper repair.

[David T. Richelderfer]

I like that reply Orman- short, to the point, logical, I suspect very accurate...  and by one who has experience and should know.

[Edward Buker]

There are leaks and then there are big leaks. The nature of our dash air system dictates that there will be some amount of lost refrigerant over time . Orman is absolutely right that a recharge that does not last any useful length of time is a waste of money and someone qualified has to find and fix the leak.

On the other hand if the system will go three months or more without a recharge, then you are kind of in the grey zone. It is probably more cost effective to add R134A as needed and I say that because finding subtle leaks is very difficult, even for shops that have good equipment and know what they are doing. Once a leak has declared itself to the point that you cannot hold a charge for a month or two then a good shop should be able to locate the leak and fix it within a reasonable amount of shop time. At least that has been my experience with refrigerant leaks over the years whether it be diagnosed using dye or a sensitive sniffer system.

Orman you may want to jump back in on this and lend some more educated guidance if my leak rates, where you are likely to be able to successfully find and cure the problem source, are off.

Later Ed

[harry kew]

I had my system charged 3 years ago by an ac shop, they went through the whole system and found no leaks recharged it. Cost was $300.00
How it just reading 70 degrees at the dash vents about 90 degrees out side
I thought I would try topping it up with one can and see if it helps
Going over the system I see the condenser fan is not coming on
The compressor clutch is in gauging
Is the fan not coming on because the system is low
If I put power to the fan wire of the relay the fan comes on or if ground the ground side of the relay the fan comes on.
So the wiring to the fan seems to be ok
Thanks for your help
1999 Patriot 40" 3126

[Edward Buker]

Harry,

I think you have a pressure switch for the condenser fan so it is possible that the system has low refrigerant and is not reaching the pressure required to turn on the fans. Some systems have the fans come on whenever the compressor is engaged but I think you have a pressure switch.

It could also be the pressure switch has failed. If you find that the system pressure is where it should be with the compressor off and the low side and high side pressure equalized (system has not be run for an hour or so) then I would not add a can. I would look at the pressure switch as a possible issue. This is a pressure vs temp chart and if your system is fully charged and the pressure has equalized then your system pressure value should be close to what you see here.

http://www.pacificseabreeze.com/tech-library/heat-and-insulation/R134a-PT-Chart.htm

If you find that you are low on refrigerant and then add some, this next link contains a low side/high side pressure vs temp chart. These values assume good air flow with condenser fans on and the evaporator fan on high (dash fan). You can turn on the condenser fans using a temporary wire change as you described, if they stay on constantly while charging pressures are able to be more accurately read. On my last coach I added a manual switch just for that purpose.

http://www.mastercool.com/media/89660-INST_web.pdf

Later Ed

[harry kew]

Ed thank you for the info
I've printed it out put it in manual for next time
Harry