Removing a split system airconditioner

[TallStreak]

Following a number of half million dollar plus quotes to renovate our post-war home, the decision was made to demolish and rebuild. I have two 1.5hp air conditioning units (daikin inverters) to remove prior to demolishing, as they are only 18 months old. Any tips on removing them myself? The company that installed them said it would cost about $500- each for them to do it.... not sure I fancy that!!!

[DavidG]

Switch to cool cycle.
Start them.
Close the compressor output line. (little screw tap)
Wait a while.
Close the input line. (little screw tap)
Switch off and disconnect pipes. Cap/plug the evaporator pipes.

Hopefully the majority of the gas will be compressed to liquid inside the compressor.

[Skew ChiDAMN!!]

David got the start of ir right but although they're relatively new and use the newer refrigerants (sans CFCs), it's still illegal to dump 'em into the atmosphere. Not that this stops cowboys. [shrug] To do the job properly, a vac-pump should be used to scavenge the remaining gases from the lines before disconnection. These aren't usually cheap to buy or rent.

I do think $500 is a bit exorbitant, unless they're including the removal of lines, etc. in a manner that leaves them in suitable condition for reuse. With the scavenged gas in a spare bottle... Somehow I doubt that patching up the installation holes would be included.

To give you a comparison, my bro (an installer) charges $500 per unit to install one. This involves a lot more work than a simple disconnection...

[DavidG]

Skew ChiDAMN
Would not all the gas be in the compressor unit in liquid form safely closed off.

The evaporator (inside unit) would be under a little vacuum so when you opened the lines air would go in rather than a little gas leak out.?

I thought capping or plugging the lines would stop any leakage of remaining gas from the inside unit.

[TallStreak]

Thanks for the info - I will have a close look at the units, and doublecheck the removal costs before I attempt anything, cheers!!!

[Skew ChiDAMN!!]

Skew ChiDAMN
Would not all the gas be in the compressor unit in liquid form safely closed off.

The evaporator (inside unit) would be under a little vacuum so when you opened the lines air would go in rather than a little gas leak out.?

I thought capping or plugging the lines would stop any leakage of remaining gas from the inside unit.

No, not all the gas. Most of it, yes.

The header & lines are under vacuum as compared to outside air pressure, but it's not an absolute vacuum. The compressor pump does a reasonable job of impersonating a vac-pump (which also doesn't remove all gas BTW, but it removes more...) however you can't run it with the valves closed & low line pressure for more than a few mins w/out risking damage. A vac-pump's designed for this and can be left running for an hour or two to achieve as close to absolute vac as possible. [shrug]

Also, on some installations where extended lines are run, more gas is needed than is included with the compressor. We add this from a seperate bottle. Trying to squeeze it all back into the compressor at a later date is unrealistic, if not unsafe...

FWIW, we use the compressor method first, not only to keep as much gas as possible in the comp unit but also to scavenge the lubricant, and then scavenge what's left in the lines with a vac-pump into an external bottle. You'd be surprised at how much more is extracted!

Line caps are really more to prevent moisture from entering the lines than to prevent gases escaping. You'd have to be pretty darned quick on disconnection otherwise! :D



Errmm... I'm not saying this is the only way to do it. I'm saying it's the only legal way. A professional who doesn't scavenge is risking his ticket and more... but I know a few home-owner's who've moved their units without. I've been guilty myself. :o

[DavidG]

Yes. I was not thinking of extended lines. They would be a problem.

Having seen the way the pro's :confused: installed mine.
Connect up one pipe.
Sitck finger over other pipe end.
Open gas 'till there is a stink.
Connect remaining pipe to evaporator.

I questioned it and was told that it was the correct way. :eek:

[Skew ChiDAMN!!]

There are cowboy's in every trade. :(

Ideally, the lines are connected, the air evac'd with a vac-pump and then left alone for a while with the gauges still attached. This is to check for leaks. If all is well, the compressor valves are opened, the unit taken for a test run, the new owner given a quick walkthrough and then the installer is on their way... Their way may save half an hour on-site, but the odds are good they'll pay for it by being recalled to trace/fix leaks and re-gas at their own expense...

It's just a pain waiting for the lines to vac down, there's not much you can do while waiting as all the hard work is already done. A good installer will run some form of protection over the lines while waiting and may do the elec's if certified. A cert of compliance should also be issued by whoever does the elec's!