A/C Compressor Out- Real Surprise

[Tex1001]

Compressor in my 42 year old unit bit the dust 15 days
ago. I'm still a contractor so costs are minimal.
New 5 ton unit for $2100. Scroll compressor (Good).
Charged with 410a (Bad).
Recover the 410a, install the unit, flush, evacuate,
charge with R22.
Surprise!
New unit draws 11.6 amps (VERY good) because
drum roll:
Old unit drew 29.8 amps.
I knew that the new units were efficient,, but WOW.
Why did I wait so long? Now I can run it off of my generator
during a power outage.

It was ALMOST worth melting in 105 deg heat for the install.

 

[Tex1001]

Want to add-
My heart really goes out to anyone who has to have
any A/C work done this summer.
I know that I don't work cheap, except for myself.

 

[sophie]

Where in the world did you find R22 refrigerant? Been scarce here for years. Last I bought for my old unit 4 years ago, I gave $80 for just over 2 lbs.
I bet you had some saved back.

 

[Tex1001]

I'm sitting on 90lbs that I bought 15 years ago.
ETA:
When I use it on a job I charge $75/lb.
I REALLY dislike the politics involved in refrigeration work.
ETA:
I meant to say I charge $75 per pound.
MY COST is $50 per pound.

 

[ZGrand]

If you got 42 years out of your first compressor, you're way ahead of the game. I thought I was doing good to get 26 out of mine.

 

[Tex1001]

It was almost 20 years old when we moved in 26 years ago.
I really know how to baby a system.

 

[Tex1001]

If you got 42 years out of your first compressor, you're way ahead of the game. I thought I was doing good to get 26 out of mine.

I just read your post completely.
The SYSTEM is 46 years old. Compressor burnout fer the old
owners was 42 years ago. I have their records.
BTW, original installation was TOTALLY botched.

 

[LVSteve]

I'm not certain if it's legal to refill a system with R22 in this state.

 

[Tex1001]

I'm not certain if it's legal to refill a system with R22 in this state.

For years I bought condenser units that were pre charged
with nitrogen for use with any legal refrigerant.
R22 is still a legal refrigerant.
I could charge a system with Coca Cola if it would work.

 

[Eric300]

Funny this post popped up when it did. MY AC coil went south on me. Just had it replaced 2 days ago. $2000.00! That stung a bit....

(*Edited for PD ) - This is a pic of the old one.

 

[Protocall_Design]

That $2000 replacement doesn't look all that great...

Edited for Eric - I was kidding.

 

[tlawler]

This is the first I've heard of someone retrofitting an r-410a unit with r-22. You didn't mention changing your AHU, so I'm assuming it's got an r-22 txv in it. I guess it might work, biggest thing would be flushing all the mineral out of the air handler so it doesn't mix with the poe. Compressors are supposed to be specific to refrigerant due to differing compression ratios, but that might just be sales hooey. It'll be interesting to see the long term effect. I do know they are experimenting with using r-32 as a drop in replacement for r-410a.

On another note, we have had excellent results converting some of our medium tonnage air cooled chillers from r-22 to r-407c. These are on York YCAS machines with 70, 85, and 100 ton circuits. Charge weight is reduced by 30-35% and tonnage is 90-95% of the r-22 performance. On the larger four circuit 400 ton machines, it comes out to 690 lb. of r-407c vs. 920 lb. of r-22. At our cost, that's $42K+ for r-22 vs less than $9K for r-407c. That's on one machine and we have close to 20 in our mobile fleet. And being mobile and bouncing down the road, they tend to spring leaks fairly frequently. I've never done it on a residential unit, but I've got friends in the resi and light commercial side that have done it and say it works well. Biggest thing again being getting rid of all the mineral oil and replacing it with poe. The advantage on the chillers is that they already use poe with r-22, so recovery and a deep evac is all that is needed.

 

[oldbrownhat]

Compressor in my 42 year old unit bit the dust 15 days...

New unit draws 11.6 amps (VERY good) because
drum roll:
Old unit drew 29.8 amps.
I knew that the new units were efficient,, but WOW.
Why did I wait so long? Now I can run it off of my generator
during a power outage....

Bravo! Your electricity supplier and other customers will be thankful for your upgrade.
Now if this project at Harvard eventually develops into affordable cooling units, A/C operating costs will drop dramatically as there won't be a compressor at all

 

[Tex1001]

This is the first I've heard of someone retrofitting an r-410a unit with r-22. You didn't mention changing your AHU, so I'm assuming it's got an r-22 txv in it.

I do know they are experimenting with using r-32 as a drop in replacement for r-410a.

On another note, we have had excellent results converting some of our medium tonnage air cooled chillers from r-22 to r-407c.

On the retrofitting, I've done it before with no problems.
I do have an R22 TXV. I don't trust my evaporator with R410a
pressures.
Compressors will work across the entire spectrum of
refrigerants. Only difference is oil and POE will be fine with R22.
I've found that head pressures in a scroll with R22 run slightly
lower.
Temp delta inside is 15F to 18F, but doesn't feel muggy.
Probably won't find any "drop in" replacements for
anything.
How do pressures/temps compare between R22 and R407c?

 

[Tex1001]

I should mention that I taught residential/commercial/industrial
refrigeration classes on a college level for 17 years.

 

[Tex1001]

Bravo! Your electricity supplier and other customers will be thankful for your upgrade.
Now if this project at Harvard eventually develops into affordable cooling units, A/C operating costs will drop dramatically as there won't be a compressor at all

ColdSNAP or dryscreen may go somewhere, someday, but it would surprise me.
It would equally surprise me if Peltier type thermoelectric cooling should prove feasible on a large scale.
At my age, I expect to be surprised at everything.
Never say never.

 

[Tex1001]

Funny this post popped up when it did. MY AC coil went south on me. Just had it replaced 2 days ago. $2000.00! That stung a bit....

Real bummer. I'm constantly surprised at how clean/clear my
evaporator is.

 

[lkabug]

I'm still feeling the pain in my wallet, having just replaced my complete unit.
Six days of high ninety degrees. Thank goodness contractor loaned me a window unit, and my neighbor loaned me a portable unit. I should be good for a few years now.

 

[Tex1001]

Six days of high ninety degrees. Thank goodness contractor loaned me a window unit, and my neighbor loaned me a portable unit. I should be good for a few years now.

In Texas, a 90 deg day comes on Thanksgiving or in March.

ETA:
I do have 4 small window units left from my teaching days.
I used 2 of them to give us a safe haven.

 

[oldbrownhat]

ColdSNAP or dryscreen may go somewhere, someday, but it would surprise me.
It would equally surprise me if Peltier type thermoelectric cooling should prove feasible on a large scale.
At my age, I expect to be surprised at everything.
Never say never.

As they say, "A pessimist is never disappointed"

They're predicting it may be ready in 5 years. It would have to be adopted by one of the major manufacturers to get it to market.

But it's an interesting line of development as we need to watch our electrical demands. I was reading recently that most portable A/C units haven't changed much in decades and use more power than they should, with a few (expensive) units being the exception.

As regards regular technology, from what I've read (and I'm not in "the biz"), the next performance improvement in refrigerants is CO2, although it works at higher pressure so can't be swapped out for current refrigerants (?) I think Mitsubishi has units in production, but only for commercial applications so far.