Need help from an A/C guru

[hdff]

Finally charging my ac, pulled vac and from what I read I need to put 3 lbs 4 oz of r12 in it. from my math from my teenage years you get 16ozs from a pound so 3lb 4oz would be 52 ounces (16x3=48+4=52). I have added 1 can of oil and 4 12 oz cans of r12 (12x4=48+4oz oil=52) , the low side line ices up but the air is not cold. what am I doing wrong or need to do. I do not have gauges to check pressures

[gable74]

Originally Posted by hdff

Finally charging my ac, pulled vac and from what I read I need to put 3 lbs 4 oz of r12 in it. from my math from my teenage years you get 16ozs from a pound so 3lb 4oz would be 52 ounces (16x3=48+4=52). I have added 1 can of oil and 4 12 oz cans of r12 (12x4=48+4oz oil=52) , the low side line ices up but the air is not cold. what am I doing wrong or need to do. I do not have gauges to check pressures

First, I'm no guru...lol

Without gauges its kind of a crap shoot, but I would first suggest taking off the inside box under the glove compartment and making sure your temperature flapper is opening closing properly. You can also make sure the heater valve is opening and closing with vacuum like it should. Maybe its just the picture and my bad eyes, but is there a vacuum line hooked to the heater valve?

[hdff]

Originally Posted by gable74

First, I'm no guru...lol

Without gauges its kind of a crap shoot, but I would first suggest taking off the inside box under the glove compartment and making sure your temperature flapper is opening closing properly. You can also make sure the heater valve is opening and closing with vacuum like it should. Maybe its just the picture and my bad eyes, but is there a vacuum line hooked to the heater valve?

had it all apart, and rebuild with a new diverter box, also put a new heater valve in and the new one didn't seem to be controlling right , both sides were hot all the time with the new one..so if you look real close right behind it there is a manual valve installed in the hose. heck down here in Texas I only need to use the heater about 2 or 3 weeks a year

[gable74]

Originally Posted by hdff

had it all apart, and rebuild with a new diverter box, also put a new heater valve in and the new one didn't seem to be controlling right , both sides were hot all the time with the new one..so if you look real close right behind it there is a manual valve installed in the hose. heck down here in Texas I only need to use the heater about 2 or 3 weeks a year

LOL..I hear ya.

If you pull that box apart under the dash (its only a few screws and the glove box insert) you can reach in and feel if the body of the evaporator is getting cold. Other than that....I will turn it over to a more experienced HVAC person . Gauges would help a bunch though.

[Eddie H.]

Since it is icing up like that, I would say that your POA and expansion valves are not working properly, but without pressure readings, there's no way to tell for sure.

[Bigdav160]

Usually it indicates an undercharged condition. Since you only put in 3lbs and not 3 1/3 lbs I'd start there.

[hdff]

Originally Posted by Eddie H.

Since it is icing up like that, I would say that your POA and expansion valves are not working properly, but without pressure readings, there's no way to tell for sure.

Humm, I had the poa and expansion valve checked and calibrated when I had the evaporator/fan housing refurbished. Guess I'll have to find someone with gauges and knows how to use them.... That's the hard part

[rsgt]

I think it is under charged.

[Jrainman]

No with that much frost you are over charged (in a liquid state you do not want that frost line reaching the compressor you blow your compressor being in a liquid state. PM me and I will walk you trough it

[DnHolland]

Try to find a local shop with an A/C tech that is familiar with working on POA valves(i.e. over 50). Without a set of gauges and accurate readings, you'll never accurately diagnose(or repair) your problem.

On a side note, the 12 oz. cans are 12 fluid ounces, the 3 lbs. 4 oz. is referring to weight. Each can is 1 pound of R-12. The oil doesn't figure into the math as your calculations imply. You probably are overcharged. You'll need a recycle machine for R-12 to correct that. It's pretty expensive if you get caught letting it go.

[Jrainman]

It may be that your TEV (expansion Valve) is not working correctly , but as you can see your frost line is way past the evap point thats why you have no cold air that frost line needs to be in the evap having the ambeint air blowing through the coil boiling off the r12 (turning it back in to a gas state , what you want is a sweaty ciold suction line after the TEV,

with out gauges it hard to tell what excactly is going on TEV/undercharge /Overchare.

with out gauges all you can do at this point is slowly release gas out (a little at a time , if you start seeing the frost line moving back (defrosting sweating) then you know you are over charged ,and little by little you want to release the R12 till all you see is a cold sweat.

[hdff]

Ok I had a chance to do some investigating today. The cable controlling the defrost door is for some reason working backwards. I removed the wire and moved the door the opposite way and the frozen suction pipe started to unfrost and the air from the vents was cool and condensate started dripping. So that problem is solved and tomorrow I'm going to get with an ac guy that has gauges and going to top off the freon to get the vents blowing cold. I am also going to investigate why the defrost door is working backwards tomorrow. It is a hard wire that hooks up one way I thought so until I can look at it it has me stumped.

[hdff]

well call me a dumb ass.. when I changed the control cables i had 2 of them switched, the defrost cable was controlling the hot cold door and the hot cold cable controlling the defrost door. now they are right and the ac is cooling just need to get with an ac guy and top off the Freon so it is cold not cool

[gable74]

Nice!

At least it was s simple inexpensive fix.

[engineer_gregh]

Thanks for posting. We've all done stuff like this. I'm curious what you find out once you've checked the system with gauges.

[hdff]

the ac guy didn't call today, maybe cause we had thunder showers off and on today and I told him I wouldn't come if it was raining.. got it out for a short drive and with a high humidity day at 92 the vents were 68* cool enough to ride with the windows up but defanately not where I want it. maybe tomorrow but I start working nites so we'll see

[gable74]

After I replaced my expansion valve, O-Rings, and dryer I vacuumed it all down and charged it. With ambient temps in the mid 80's and a little humidity I was getting 38 degrees at the center vent at idle with the RPM @ 2000. Once you get yours charged up and dialed in it should not be any warmer then 40 degrees out of any vent I wouldn't think.