Air Conditioning

[barry boyette]

Hey all. I'm new to this forum, been lurking for a while; but, thought I'd throw my $.02 in. Adding freon and doing a little of your a/c work is really no big deal. For example, make sure your condenser is clear of dirt and debris. It must flow air to work.Then, locate the big hose coming into the a/c compresser on the engine. The compresser is mounted to the front of the engine and has a fan belt that turns it. There are two hoses coming out of it. The big one is the low pressure side and the little one is the high pressure side. The low or big one should be cold and have water droplets on it when running and the high side will be hot to the touch.

While under there looking around, locate the service port which should be on the low pressure (big hose) somewhere. It looks like a valve stem for your
tire. That is where you put freon in. The little hose or high side should also have a service port on it. Never add freon here. The high side port should only be used for checking the high pressure when utilizing a set of a/c gauges.

Wal Mart sells kits for adding freon that has a little gauge included. Attach thehose to the low side service port with the engine cut off. Look to see what the pressure is with engine stopped. A good rule of thumb is the static pressure should be about the same as the outside ambient temp. If it's zero then you need to find someone that can service your system from scratch. If it's got some pressure on it then you can probably proceed.

Locate the freon site glass. You will need to watch this while adding freon. Next, start the engine and turn the a/c on. Look to see if the
front of the compresser is turning. If you're not sure shut the motor off and look at the front of the compresser while it is off. Now, restart the engine and check to see that the front of the compresser is turning. This lets you know if the clutch is kicking in and trying to circulate freon. Sometimes, you have to put a little freon in before the clutch kicks in. Simply open the freon valve and let some of it into the system. Some people hold the can upright and some upside down. I like to turn it upside down because it gets into the system quicker without trying to freeze up the can. Continue adding freon and watching the sight glass at the same time. If the system is low on freon the sight glass will have bubbles in it. They look like they are racing by at light speed. If you have converted to 134A stop putting freon in when the bubbles are almost gone. If you are still using R12 or one of its
cousins, keep adding until the bubbles are gone. While you are adding freon the blower will start to blow colder air. Depending on the charge in the system it could take several cans to fully recharge. It's probably better to have to little freon than to much. The low side when full of 134A should read between 14 to 35 pounds on the gauge give or take. A lot can influence this like outside temp and how much air is flowing across your condenser up top. On our crop dusters we have installed double condensers with double fans and we are seeing low side pressures of 10 - 15 and high side a little over 100 pounds even on a hot day. The condenser is the secret. Keep it clean and make sure it's flowing air.

When we started fooling with a/c on our crop dusters we didn't even know what the condenser did. Now we build our own systems using off the shelf parts for big trucks and ambulances. It
is a little scary at first but there is not a lot to it. Spending 600-700 dollars recharging a low system is highway robbery when you can do it yourself for $50 or less.

One other thing, I've found over the years a lot of differences of opinions when it comes to air conditioner work. What works for me may not work for you. If you have specific questions feel free to email me with your questions.

barryb