Another junk tool?

[Stephen Newell]

I bought a air conditioning vacuum pump to work on my car's AC. It's brand new and I ran it for 15 minutes and it got really hot so I shut it off. It don't seem normal, should I attempt to return it?

 

[sms]

It can't hurt to try. Sometimes it is hard with electrical items but I would try anyway.
I have a HF one here that I inherited that worked fine when I needed it

 

[Fixingfarmer]

At least it’s closer to reasonable in price I had one of those that was 6 times the cost and then replaced it with a couple hf pneumatic ones for 17 dollars a piece they were much more reliable over 15 years. I’m sure they are 25 bucks now

 

[Stephen Newell]

At least it’s closer to reasonable in price I had one of those that was 6 times the cost and then replaced it with a couple hf pneumatic ones for 17 dollars a piece they were much more reliable over 15 years. I’m sure they are 25 bucks now

I had a HF pneumatic one that I had used a couple times but it quit. I had always wondered if the AC wasn't working very good because of that pump so I tried to replace it with a better one. I've just never used one so I don't know if it's normal for one to get that hot. Since I posted I found a card that came with it warning "Hot Surfaces do not touch" so I don't know.

 

[Fixingfarmer]

The gauge set will tell you if it’s working. A vacuum is a vacuum if it’s drawn down between 25 and 30 and you pull that for 15 min followed by a leak check for 10 min. Then charge.

I would suggest going to get another one of those plastic pumps till you get a good one I always had a spare because they do seem cheap they do like to unthread from the Venturi but the second one has lasted a long time I haven’t had to unbox the third one

The electric ones are at least as big a gamble and way more$$$

 

[Stan Coryell]

Did it come with oil in it? Is the oil level correct? I'd probably change the oil and try it again.

The oil picks up the moisture you are removing from the system. If mine sits for a few months, I change the oil before use and usually every system I pump down (houses).

 

[Stephen Newell]

Did it come with oil in it? Is the oil level correct? I'd probably change the oil and try it again.

The oil picks up the moisture you are removing from the system. If mine sits for a few months, I change the oil before use and usually every system I pump down (houses).

It didn't come with oil in it but came with a bottle of oil which I filled it with. There is a sight glass on the end of it so there isn't any doubt it has oil. Wouldn't the oil get milky if it picked up moisture from the system? It remained clear.

 

[Stephen Newell]

The gauge set will tell you if it’s working. A vacuum is a vacuum if it’s drawn down between 25 and 30 and you pull that for 15 min followed by a leak check for 10 min. Then charge.

I would suggest going to get another one of those plastic pumps till you get a good one I always had a spare because they do seem cheap they do like to unthread from the Venturi but the second one has lasted a long time I haven’t had to unbox the third one

The electric ones are at least as big a gamble and way more$$$

It does produce enough vacuum pressure but I had a hose completely off of the system. Someone told me I should then do an overkill with the vacuum and the net said I should run the pump 30 to 45 minutes anyway. I had planned to do that a couple of times before charging, especially since I charged the system with compressed air to find a leak. It held 50 psi overnight so I let that out and hooked the vacuum pump to it.

The HF pheumatic pump I had would only product 18 to 20 negative pressure where this electric one is pulling 28 so I think it was worth buying if it's not on the verge of burning up.

 

[olddavid]

They tend to run hot but if you ran it for 15 minutes sucking on atmosphere it might get hotter. It might also blow oil out. You actually won't be able to tell how much moisture is in it, but it doesn't take much to cause problems. Edit: Actually, most of the water should go out the pump exhaust as water vapor.

 

[Fixingfarmer]

It does produce enough vacuum pressure but I had a hose completely off of the system. Someone told me I should then do an overkill with the vacuum and the net said I should run the pump 30 to 45 minutes anyway. I had planned to do that a couple of times before charging, especially since I charged the system with compressed air to find a leak. It held 50 psi overnight so I let that out and hooked the vacuum pump to it.

The HF pheumatic pump I had would only product 18 to 20 negative pressure where this electric one is pulling 28 so I think it was worth buying if it's not on the verge of burning up.

With a hose off that is perfect it tells you you need to shut it off and fix the problem (connect the hose) instead of wasting billable time. The cheap red one should pull 25.

Do what you like it should work fine but the moisture you are boiling out doesn’t care what is pulling the vacuum or that last 5 just that it’s there and the leak check with all your valves shut verifies you actually have a sealed system. The boiling occurs as soon as you have the vacuum on the gauge because the water is already at your air temperature. Most of the ac machines I’ve run the automatic mode is set to 15min and 10 min.

half hour of running that poor electric pump you are concerned about is not necessary.

 

[jdeere562]

Guy I knew used an old surge style vacuum pump from a milker. Had to hooked to a reservoir tank and gauge. That old thing would pull a vacuum real quick and worked just fine.

 

[Stephen Newell]

With a hose off that is perfect it tells you you need to shut it off and fix the problem (connect the hose) instead of wasting billable time. The cheap red one should pull 25.

Do what you like it should work fine but the moisture you are boiling out doesn’t care what is pulling the vacuum or that last 5 just that it’s there and the leak check with all your valves shut verifies you actually have a sealed system. The boiling occurs as soon as you have the vacuum on the gauge because the water is already at your air temperature. Most of the ac machines I’ve run the automatic mode is set to 15min and 10 min.

half hour of running that poor electric pump you are concerned about is not necessary.

I had a mechanic convert the car from R-12 to R134. Long story short he was a terrible excuse for a mechanic and I've been trying to fix his work for the last couple years. I determined the cycling switch wasn't working right so I ordered a new one. Then I found out it wouldn't fit in the space the other one did. Come to find out in order to fit one in there he used a switch made for the high pressure line on the accumulator. The port on the front was used to charge the system so I had to put the switch there. That left no way to charge it so I took the low pressure hose off and had NAPA put a tee in the middle of it with a charging port. The system had been open to the humidity for several days to get this fixed so I'm trying to vacuum as much moisture out of it as I can.

 

[Fixingfarmer]

What’s it on? The accumulator might be a desiccant filled drier you could replace that and be double extra sure it’s working

 

[Stephen Newell]

What’s it on? The accumulator might be a desiccant filled drier you could replace that and be double extra sure it’s working

It's on a 1993 G20 Chevrolet van.

 

[Fixingfarmer]

Quick google search of a dryer for that vehicle does show one that does also include a low side port so I’m not saying 100 percent it would fit but that might be part of mystery. There’s another style more of an inline affair with hoses

If he converted it sometimes a kit will come with an accumulator but without being the one to do it I’m afraid it’s an anyone’s guess as to what was done

 

[Stephen Newell]

Quick google search of a dryer for that vehicle does show one that does also include a low side port so I’m not saying 100 percent it would fit but that might be part of mystery. There’s another style more of an inline affair with hoses

If he converted it sometimes a kit will come with an accumulator but without being the one to do it I’m afraid it’s an anyone’s guess as to what was done
View attachment 157724

That is what I have. The problem I had is the cycling switch needed to go on the port on the back side. There is less than 2" space between the accumulator and the firewall so I had to cap that off and put the cycling switch on the front where the charging port is shown. I had to have a charging port installed on the low pressure line going to the compressor. It's all put together now leak free and I'm in the process of vacuuming the system.

 

[Hobo,NC]

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

 

[olddavid]

Good points Hobo,NC. At my old job I had to work some with high vacuum systems. Just because your gauge says it's pulling 32 inches of vacuum does not mean you have a really high vacuum. A really good mechanical vacuum pump can pull down to maybe 10 microns if you cap it off but if the system you are pulling on has a tiny leak it won't get close to that but a gauge may still indicate 32 inches.

 

[Hobo,NC]

Good points Hobo,NC. At my old job I had to work some with high vacuum systems. Just because your gauge says it's pulling 32 inches of vacuum does not mean you have a really high vacuum. A really good mechanical vacuum pump can pull down to maybe 10 microns if you cap it off but if the system you are pulling on has a tiny leak it won't get close to that but a gauge may still indicate 32 inches.

 

[olddavid]

That sounds like a good procedure if you don't get confused and do it wrong like I would. At work we had Helium cryogenic compressors. A couple of times we had to flush the compressors with Helium to get contaminants out.