New hvac condensing unit replacement questions

[1oldtimer]

Ok, my moms early 90's Carrier developed a big leak at the service port block area. With the quoted price of R22 I'm leaning towards a new Carrier unit. I keep reading on posts about a "good installation" being the difference between longevity and failure. I work on vehicles and equipment for a living and understand the basic principles that can cross over into the HVAC world but I want to know what I'm looking at when it's done.

1. What should I look for in a proper installation.
2. How do I know which model is best for her house (and size, can I just go by the old unit label).

Or
3. Get the repair done, buy a 30lb bottle of R22 and a good set of gauges and charge myself ......I would totally do this option if it was my house, but it's my moms place.

 

[yeldogt]

I have fixed old units vs replacement -- like anything else it's a question of what failed and how much.

Fixing a mechanical problem that caused the leak may be worth doing to get a few years out of a unit ... fixing a corrosion leak on the other hand would not. That's the first of many to come.

The reality is at 25 years the whole thing needs to be replaced if fixing is out -- sizing is based on doing the load calculations. Is there a furnace also -- heat pump?

 

[LS6 Tommy]

I have fixed old units vs replacement -- like anything else it's a question of what failed and how much.

Fixing a mechanical problem that caused the leak may be worth doing to get a few years out of a unit ... fixing a corrosion leak on the other hand would not. That's the first of many to come.

X2. You can repipe the condensing unit and bypass the existing service valve block, braze in new service ports, suction filter drier and liquid line drier, leak check, evacuate and charge, but it may be just as expensive as a replacement when you add up the labor. If you're looking at replacement, the entire system has to be done as you can no longer get R22 equipment.

No insult intended, but from your questions, it doesn't sound like you should be attempting the work yourself.

Tommy

 

[alexb2000]

I just replaced a 90's Carrier with a 20 SEER Lennox. Those Carriers were great units. The issue IMO is that over time all of the original quality Carrier components get replaced with Chinese **** ie. capacitors, fan motors, timers, etc. and those Chinese component begin to fail with great regularity making the unit expensive to keep.

Just my .02, but I would replace the entire system, you've gotten your money out of it.

 

[TangoFoxTrot]

I don't think you can buy new R22 condensing units any longer. Which is more EPA silliness costing consumers out the ***.

I know you can "frankenstein" a 410 condensing unit in there, but my guess is most installers wouldn't do it.

Probably best at this point to just replace the whole thing or see if it can be economically repaired.

 

[acmikee]

repipe the old unit or buy a dry condensing unit and use R22.

 

[brewchief]

At 25 plus years old it's time to replace everything, is it connected to an air handler or a coil and furnace? Air handler or coil will need to be replaced as well and if the furnace is the same age it's due as well.



Sent from my SM-G965U using Tapatalk

 

[LS6 Tommy]

...buy a dry condensing unit and use R22.

You can't. Dry units were banned by the EPA 3 years ago.

Tommy

 

[yeldogt]

I was forced to relocate a 4 ton York Condenser about 10 years ago when doing some remodeling .. it had to be 20 years old at the time. What a beast .. huge .... never gave me any problems and it was surprisingly quiet. Heavy. It had been installed a few years before I brought the property.

The unit was a tad oversized for the house ... but, I was debating on what I was going to do with the property. Replacing the unit with new at that time could be incorrect for the final situation with the house. We pumped it down .. moved it and the pad .. it ran faithfully until I put the new system in a few years ago.

Some of those old systems could make ice in Texas -- it used more electric. But, I would have never had a positive return replacing it

 

[1oldtimer]

No insult intended, but from your questions, it doesn't sound like you should be attempting the work yourself.

Tommy

None taken, I'm not doing it myself I just wanted to be able to have an idea of what I'm looking at after the install is done by a professional. I have done some more reading and answered some of my questions. The components and some theory is the same as automotive and others different. IF I had a/c in my house I would attempt the o ring repair on the low side service port that this unit needed. But since it's my moms I'm not here enough to watch it.

 

[Bronson]

I told a AC friend of mine that I found a full R-22 jug in my shed that I forgot I had.
He offered me $600 for it, sight unseen.
I installed a new Carrier ( I used to be a HVAC Tech) in 93, on my home, along with central heat.
I guess I did a good job, I have never had to add an ounce of Freon sine I installed in 93.
If I sell the jug of 22, it will begin to leak immediately.

 

[yeldogt]

None taken, I'm not doing it myself I just wanted to be able to have an idea of what I'm looking at after the install is done by a professional. I have done some more reading and answered some of my questions. The components and some theory is the same as automotive and others different. IF I had a/c in my house I would attempt the o ring repair on the low side service port that this unit needed. But since it's my moms I'm not here enough to watch it.

Well -- if it was just the valve in the port and the thing looks OK -- just replace the valve and fill it up. Replace the other as well.

Are you sure it all leaked out ... possible ... but often they don't leak all the pressure

 

[Git]

Seeing that you live in S Cal - don't forget to factor in the cost savings in electricity by installing a newer unit

 

[1oldtimer]

Well -- if it was just the valve in the port and the thing looks OK -- just replace the valve and fill it up. Replace the other as well.

Are you sure it all leaked out ... possible ... but often they don't leak all the pressure

The tech put his gauge on it and it was pulling a vacuum.....so it was empty. I did see oil residue and heard hissing coming from the block which looks like the factory shutoff point when they pre fill the unit. It looks like it's a super common leak point, some have had luck replacing the O ring, some made seal kits and other just replaced the block.


He installed a Colman condensing unit and charged it with 407C, it works great now. We'll see how long the inside unit lasts....it was about $3200 (with a new disconnect) with a completely new inside/out units costing $6300.