Another junk tool?

[Stephen Newell]

Yes a vacuum pump will run hot somewhere in the 130 to 140 range. You can use a fan to cool it some.

On your switch issue they made a Tee for that those T's are hard to find now.

I doubt you will ever get all the moisture out of the system using a vacuum pump only you would have to be tooled up well and dedicated to the cause. If you are sure you do not have a leak I think the best you can do with what you have is turn it on and walk away from it for a day. After a day change the oil in the pump and run it another day.

What you are doing will never confirm you are pulling down low enoufh to be effective and you will never know if you are doing any good at all so at the least pump pump away hopefully some good will come out of it.

If you want to know more about the subject Microns

I never heard of the word micron in refrigeration before. The gauges I have show both vehicles I'm working on a negative 28. According to google that is 7,112 microns. I think I have it ready to charge, for the first time since I've worked on it, I think I've found all the leaks. I put 50 psi compressed air in the system and let it sit overnight with no leaks. I ended up running the vacuum pump six times on each vehicle for about 10 minutes before cutting it off. When I ran it for 15 minutes I think it got above 140 degrees, you couldn't put your hand on it and leave it. This is why I was wondering if the unit was defective.

 

[Stephen Newell]

That's some system. I think in my case, one car there wouldn't be enough R-12 left in the system to hurt anything. The AC hadn't been used in 10 years or more because the compressor went out. I had to install a new compressor and convert it to 134. I found the evaporator had a leak so I had that flushed and repaired. Then the R-12 hoses had to be replaced. All that left was the accumulator which I purchased a new one. The condenser, I had that flushed and checked when I had the evaporator repaired. It's practically all new, I just need to get the air and what moisture from humidity out of the system I can. The other car the mechanic did I don't know if it was flushed out or not. I know I've had it apart several times trying to fix all the stuff he screwed up.

 

[joeysmith]

The only way to know you have the moisture out is a micron gauge.

Compressed air is usually chocked full of moisture


The moisture gets in the oil an takes a long time to boil out which shows up on the micron gauge


I have spent hours/days pulling a vacuum to dry systems out before


The pump will get pretty hot on a hot day
Hot enough you dont want to touch it.


If you have an amp meter you could see if its pulling more than it should

Might give some insight into of its junk or not

 

[Stan Coryell]

No, the vacuum pump oil won't look milky. Hobo and Joey are spot on.

 

[Fixingfarmer]

I would not add compressed air that just introduces more water each time and needs to be removed. or any other gas. He likely changed out the compressor during the conversion?? so it’s fresh when he converted it and probably hasn’t wadded up with a bunch of metal inside at the very least so while there’s chances of it not working or being plugged from debris that was already in there it won’t cause a kick out like the sensor you are describing compressor will still be trying to go pressures just won’t be right.

1 Replace dryer 2 then vac. 3 test that it holds the vac. 4 then let the dryer do its job and fill it with r134a

 

[Stephen Newell]

I would not add compressed air that just introduces more water each time and needs to be removed. or any other gas. He likely changed out the compressor during the conversion?? so it’s fresh when he converted it and probably hasn’t wadded up with a bunch of metal inside at the very least so while there’s chances of it not working or being plugged from debris that was already in there it won’t cause a kick out like the sensor you are describing compressor will still be trying to go pressures just won’t be right.

1 Replace dryer 2 then vac. 3 test that it holds the vac. 4 then let the dryer do its job and fill it with r134a

I had a very minor leak I couldn't find. Using the vacuum pump only let me know I had a leak which I already knew. I was having to charge the system every couple weeks. Using compressed air I was able to put soapy water on all the joints until I found it. I don't have the equipment to flush the system with nitrogen and there probably isn't a qualified mechanic within 50 miles of me. None in my town I can trust to even change the engine oil.

 

[Fixingfarmer]

I had a very minor leak I couldn't find. Using the vacuum pump only let me know I had a leak which I already knew. I was having to charge the system every couple weeks. Using compressed air I was able to put soapy water on all the joints until I found it. I don't have the equipment to flush the system with nitrogen and there probably isn't a qualified mechanic within 50 miles of me. None in my town I can trust to even change the engine oil.

I’m glad you found the leak. We use a small amount of dye and yellow glasses with a black light. It’s safer for the components and you aren’t adding something you shouldn’t to the system. Gas or liquid there’s no reason for anything else to go in other than refrigerant dye and refrigerant. I can’t tell you how long the jug of ac flush has been on the shelf.

The same steps as above remain and must be performed in the correct order since compressed air was added.

1 replace dryer add a couple ounces of the correct oil for the compressor if you haven’t you said there was a leak.

2 vac

3 test vacuum by closing manifold valves and waiting 10 min

4 charge be sure to bleed manifold and not lose your vacuum.

The 21 bucks for another can you would burn up by running the vac for a week to attempt to pull it out of the desiccant. That’s if the pump survives. It very well might I’m supposed to be more of an optimist

 

[Stephen Newell]

I’m glad you found the leak. We use a small amount of dye and yellow glasses with a black light. It’s safer for the components and you aren’t adding something you shouldn’t to the system. Gas or liquid there’s no reason for anything else to go in other than refrigerant dye and refrigerant. I can’t tell you how long the jug of ac flush has been on the shelf.

The same steps as above remain and must be performed in the correct order since compressed air was added.

1 replace dryer add a couple ounces of the correct oil for the compressor if you haven’t you said there was a leak.

2 vac

3 test vacuum by closing manifold valves and waiting 10 min

4 charge be sure to bleed manifold and not lose your vacuum.

The 21 bucks for another can you would burn up by running the vac for a week to attempt to pull it out of the desiccant. That’s if the pump survives. It very well might I’m supposed to be more of an optimist

I tried the dye first and it didn't reveal the leak. On one of the vehicle I added a couple ounces of fluid directly to the compressor. The other one I installed a new compressor which had oil added to it when it was installed.

I know the system is now sealed, both vehicles I charged with 50 psi air and they both sat overnight with no pressure change. The leaks I've had were so minor it would take more than 10 minutes to show up.

The compressor I have I think if I ran it for a week it would be glowing red if not burning up. I didn't feel safe running it for more than 10 minutes at a time. I could go back to doing that.

 

[Ozlander]

Of course it got hot. It's an air pump and an electric motor. Pumps get hot from pumping and electric motors get hot from running.
Did you expect it to get frost on it???

 

[Stephen Newell]

Of course it got hot. It's an air pump and an electric motor. Pumps get hot from pumping and electric motors get hot from running.
Did you expect it to get frost on it???

I've been working with air compressors and machinery all my life. Usually when a tool gets excessively hot the motor locks up and quits. I don't have a way to measure the temperature but I suspect after running it 15 minutes it's in excess of 200 degrees.

 

[joeysmith]

I've been working with air compressors and machinery all my life. Usually when a tool gets excessively hot the motor locks up and quits. I don't have a way to measure the temperature but I suspect after running it 15 minutes it's in excess of 200 degrees.

Maybe they forgot to install the little fan that goes inside the motor

Usually can peek in there an see them through the vent holes

 

[Hobo,NC]

Anything I say is not meant to be negative toward how you are doing this. BTDT I got the tee shirt.

An anolog gauge can not show a small leak in 10,15 are even an hour its not possible for you eyes to see the difference in needle movement. You may not see a small leak in 24hr that's why a digital gauge set has became a must have tool for a pro.

AC work is probably the most hacked DIY repair out there. AC repair is not taught correctly by most instructors as they are not keeping up with new technology . After I started watching Tom Lech I wounded how I got away with all my hack AC repairs. For the new guy that's starting to tool up for AC work follow Tom he will cost you some money but you will be at the top of your game. I don't expect you to go out and buy all this stuff.

I just offered a bit of education on the subject I wish the best for you it may just work out.

Digital Refrigerant Manifold w/ Micron Gauge

 

[Stephen Newell]

Maybe they forgot to install the little fan that goes inside the motor

Usually can peek in there an see them through the vent holes

There is a fan in the back of it but there is little or no air blowing. It's just flat fins parallel to the motor shaft. The body of the motor is all solid with the pump on the front. There isn't a way air could pass through it anyway. Nothing like a typical electric motor.

 

[Stephen Newell]

Anything I say is not meant to be negative toward how you are doing this. BTDT I got the tee shirt.

An anolog gauge can not show a small leak in 10,15 are even an hour its not possible for you eyes to see the difference in needle movement. You may not see a small leak in 24hr that's why a digital gauge set has became a must have tool for a pro.

AC work is probably the most hacked DIY repair out there. AC repair is not taught correctly by most instructors as they are not keeping up with new technology . After I started watching Tom Lech I wounded how I got away with all my hack AC repairs. For the new guy that's starting to tool up for AC work follow Tom he will cost you some money but you will be at the top of your game. I don't expect you to go out and buy all this stuff.

I just offered a bit of education on the subject I wish the best for you it may just work out.

Digital Refrigerant Manifold w/ Micron Gauge

The micron gauge would be nice but at that price pretty forbidding for the DIY. The most I could do is empty a bottle of argon and have it charged with nitrogen. I still wouldn't have the micron gauge to manage it.

 

[Fixingfarmer]

The micron gauge would be nice but at that price pretty forbidding for the DIY. The most I could do is empty a bottle of argon and have it charged with nitrogen. I still wouldn't have the micron gauge to manage it.

The micron gauge is forbidding for more than just the diyer. It’s been the hot new thing for awhile now but in a shop if you already have to have a recovery machine to cover your buns that’s usually where the micron gauge fun money would be spent.