How do you "pump down" an home AC compressor?

[_RaT_]

I need to cut the freon lines to my AC compressor to move it about 16". I am also pouring concrete to a completely different level then the little 4' X 4' slab it sits on so I will need to move it out of the way. I was told that if it has valves, I can pump it down thereby taking the freon in the copper lines and put it in the compressor. Can I do this or would I be better to just let a pro do it? It is a 2001- 5 ton Trane with the valving very easily accessable. Thanks

 

[nappy]

Rat,
I would suggest to let a pro do it, It's not rocket science but you need two tools to make ti happen. refrigeration gauges,allen hex key set, one for each
line size.With these two tools you can pump down your system, This only cover the pump down, to reinstall more tools are required.again I suggest to let a pro do it. But if your game and have these two tools,
response to this post again and I'll walk you thru It.

Nappy

 

[Sigarms]

Nappy, can I ask how do you pump down an A/C system with a set of gauges and hex key set?

 

[Willl]

to reinstall more tools are required.

It'll be cheaper just to call a pro.

 

[Birdhunter1]

You can pump it down without a set of gauges if you know what you are doing but since you are asking how to do this I am going to assume you have never done it.

You can pump it down by closing the liquid line (small one) and when the compressor starts to pull hard you have it pumped down. But to reconnect everything you have to braze the lines to gether (not like sweating copper water lines) and then flush with nitrogne and pull a vaccum. So by the time you have bought or borrowed all the equipment you are way over the expense of paying someone to do it for you.
If you are just moving the unit a little ways it probably won't take an a/c guy long to do it and you are probably looking to spend about $100-$150

 

[RonMar]

Let a pro do it. Once a system is vented to the atmosphere, it must be "pumped down"(placed under a vacume) to get as much of the air and moisture out of the system as possible. This is a time consuming process at whatever you are paying for the service tech per hour. It also requires a special vacume service pump. A new line dryer will probably be reccomended as exposure to air quickly saturates the installed one. Once completely purged of air, a new refrigerant charge can be added.

Consult with a service tech and show him exactly what you want to do. There may be certain things that can be done before hand to isolate parts of the system and retain much of the refrigerant, making the recharge of the system much easier and require less labor hours. There may be valves on your system that could allow you to do much of this yourself as you were asking about. But even if you are able to pump most of the referigerant back to the compressor, once open to the atmosphere, the system will still need to be evacuated properly to restore normal function and efficiency.

 

[nappy]

Rat/Sigarms

Willl is right call a pro, It's cheaper and safer! Iam not a hvac service tech. But been in the trade for 42 years (sheet metal background) i have pump down many ac compressors in my day.

Sigarms, to answer your question "in general". here's the steps to do a compressor pumpdown:


1. Go to theomstat location and set to off settings.

2. go outside to ac condenser and install refrigeration gauges.make sure to place each on right port (for moderatoring only) Make sure you have a electrial disconnect box
in reach or close by (code required) you'll need this later.

3. ajust t-stat to cooling, fan on or auto and lower temp. to lowest setting. This will insure system will
not cycle off in the middle of pumpdown.

4. go back to the condenser and it should be running, there two copper lines that run from the inside unit (Air handler)
to the condenser. 5 ton Trane 1 1/8" and 3/8"

5. Quickly valve off the 3/8" line with the allen hex tool.

6. Now start looking at the refrigeration gauges, the 3/8" line will read "zero" and the 1 1/8" line will start dropping, when it
gets to zero, very fast valve off this line, when done, reach up and turn off electrial disconnect box.

At this time all the system refrigeration is in the ac compressor, in the trade this is called a pumpdown.This is by no means a full
detailed pumpdown. Please call a hvac pro to do this task, it'll be cheaper and safer in the long run,anyway this is only the 1st.
half of a system pumpdown, you'll have to reinstall later and this runs into more issues for a non pro.

nappy

 

[Willl]

Not to be a party pooper, but if your not EPA certified, it's against the law for you to DIY.

 

[WhyNot]

Not to be a party pooper, but if your not EPA certified, it's against the law for you to DIY.

Unless it is 410a but, then you need a high pressure license at least here in NJ.

 

[Bill Barrett]

Oh what the heck it's only ozone.