2-135 air conditioner again

[rrlund]

OK,I've got 2 unrelated problems with the 2-135 Series 3,so I'll make 2 seperate posts. How much refrigerant does that system hold on the series 3 2-135 air conditioner unit? I hooked a jumper wire to the compressor today,put in two 12 ounce cans of 134a and it cools down,doesn't frost up the lines,but cools. I hooked the wires back together and the clutch still won't kick in on it's own without a jumper. I opened up the top of the cab,have power to everything. Traced everything down and have power to one side of what I think is the low pressure switch. It's the 2 pronged sensor on top of the filter dryer. If I pull those 2 wires off the spades and hook them together,the clutch kicks in and it works. So I assume I either don't have enough refrigerant in it yet of the switch is bad. The manual that they gave me when I bought this thing 7 or 8 years ago isn't for a series 3 and only shows a high pressure switch,doesn't show anything but a sightglass on top of that filter/dryer. When I was looking it over last week,those 2 spades were bent together and touching. I think I probably did it with the pressure washer or something,but now I'm wondering if somebody bent them together to make it work. You'd have thought I'd have noticed before this. Would it hurt to run it with those wires spliced together if there IS enough gas in it and the switch is just bad?

 

[Anonymous-0]

With the pressure switch bypassed, does the A/C compressor cycle on and off? If it does, this would indicate the high press switch is working properly and OK to run with the wires together. I don't have my book with me right now or I'd look up the charge amount. Remember that R-12 charge compared to 134a charges are different amounts. My guess would be around 2.5 lbs. Is the sight glass on the drier clear when the compressor is running or foamy. If it's foamy it's low.

 

[rrlund]

I didn't run it long enough to see if it would cycle on and off. Just hooked them together in front of the shop door and the clutch kicked in and it cooled. That site glass is so small and dark,I can't see anything in it. I didn't have my glasses with me,so that didn't help the situation. If it takes 2.5 pounds and was completely leaked out over the winter,24 ounces would leave me with quite a ways to go. I'll try a couple of more cans one at a time and see if I can get some frost on the line at the compressor. I just didn't want to overfill it.

 

[Wayne11797]

No frost at the compressor can be a correct or overcharge. The refrigeration suction lines should be wet and cold. Get your glasses and get a good look at the sightglass. You said "the clutch kicked in and it cooled" your of to a good start. There's nothing more fun then to figure out someone else's electrical reconfigurations, or field adjustments. Don't get into a hurry to add more freon just yet.

 

[bhc41051]

I would stay away from R-134 There"s a product called FreeZone, It"s a direct drop-in for R-12 doesn"t require flushing, lubricates your seals and hoses and operates at a lower pressure..just my two cents....

 

[Ken Macfarlane]

You may wish to read up on conversion to propane if you have a lot of problems to track down and leaks to fix.

 

[Jeff Weisensel]

Can you put a set of gauges on it or have you? Then the guess work is over. Depending on the low side switch, they usually cut power to the compressor when they get close to zero and lower. You could have a bad low pressure switch. If with gauges on it and actually does have low suction side pressure (zero and below)it could be numerous other problems. But if you say it does cool it should be working. Make sure the condenser coil and evaporator coil is free of all dirt and air can flow thru both.

 

[e]

How about picking up a manifold gauge set? They are not much money and will narrow it down to a charge issue or an electrical issue. You are really flying blind now without gauges monitoring the low and high side.

 

[rrlund]

It must be the low pressure switch. I put another 12 ounce can in it this morning. Crimped 2 male spades on a short piece of wire and bypassed it.Taped them and zip tied everything up out of the way. It cycles like it should,cools good. Good enough for now. Now I ran a rock in the V Max spreader and split a gear box. So...there everything sits while I wait for parts for that. Nice day to be sitting doing nothing anyway.

 

[Brian Jasper co. Ia]

Receiver driers are usually on the high pressure side of the system. Compare the line sizes going to and from the evaporator. The high side lines are nearly always 1/2 the diameter of the low side hoses. It sounds like you have bypassed a high pressure cutout switch designed to protect the system in case the condenser gets plugged or the engine fan isn't pulling enough air.