Central Air Central Air Compressor Died - Brand Recommendations?

[olds70supreme]

My 1993 Lennox compressor unit died, I'll be calling the local HVAC places tomorrow. One reps Lennox, the other Carrier and Rheem. I'm assuming most of these would be "Chevy vs Ford" recommendations, but are there...

-any obvious losers (aka modern York) companies to avoid?
-any "must-have" features to get (variable frequency, etc...)?

Also, does paying for a more expensive model realistically give you more years of service/reliability?

Should the condenser be replaced as well (not sure but assume it is from 1993 as well)?

Thanks.

 

[nadogail]

IMHO, you will be well served to consult an independent service company who is not in the sales and business.

Can you imagine going into a Barber Shop and asking "Do I need a haircut?

 

[yeldogt]

Being that old ... you are going to need the evaporator changed as well. All the single speed equipment is about the same. You don't want the builder line -- the middle stuff has better cabinet and fan design .. compressor blanket ... larger case typically. This make for durability and quiet operation. Most times the rebates make the next step up the best buy anyway. Durability -- as much about proper install as anything

Make sure to check any state programs -- some states have unbelievable programs. Grants and cheap loans if you follow the rules.

do you have a furnace as well?

The higher end multi speed equipment w/ VS fan motors are really about comfort ... they can cost less to run ... but, it's the ability to match the load needed that makes them shine. Especially in a humid climate.

 

[Motown]

Just had the top of the line Carrier A/C and furnace installed. Very happy so far. Super quiet. My energy company's had a bunch of rebates, as well as Carrier. Saved almost 4k.

 

[olds70supreme]

Had a guy out to look at the install and give me a quote. He gave me a number for the entry level 13 SEER unit and kept steering me back to it. That surprised me because I assume that install is the same between entry level and expensive, and there would be more profit in the expensive unit (?).

 

[Rusty Fords]

over 26 years in the HVAC trade from Install, Fab to service work.

1st company I worked for was a Carrier dealer I carried 2 circuit boards don't remember changing out very many. 2nd company a Lennox dealer carried 2 full shelves of circuit boards replaced them almost daily.

Owner/operator for 8 yrs I installed Carrier equipment (Install the best, work on the rest).

Most all manufactures use the same brand of Compressors, contactors, Fan motors etc... The components are just built to the engineered specs that Carrier, Rheem, Lennox… specifies.

All that being said sounds like you got a lot of good years out of that Lennox unit.

Higher efficiency equipment isn't always worth the added cost please check out this site http://sagoro.wrightsoft.com/Carrier/Default.aspx its a Carrier site and you can compare operating savings from one unit to another. Please don't look at the $ saved but figure a % saved.

Motown You should look at the cost savings of a H/P over a gas furnace I put a lot of H/Ps on gas furnaces and cut customers gas heating bill by 2/3 and for only about $1000 more in installation costs.

 

[99LeCouch]

Depends. The multi-stage stuff can need additional wiring run if it's non-communicating, thermostat set up to run the multi-stage system, and could lead to callbacks if it's set up poorly.

Sounds like this particular installer may not want to be on the hook for setting up a multi-stage system and coming back out when a customer doesn't like a setting. Or if the 2nd stage cool wire gets damaged in the wall and the unit stays in low stage on the hottest day of the year, stuff like that.

Not bagging on that person, but if multi-stage equipment is what you want, might want to find an installer who wants to take the time to set it up right. That person will probably be more expensive than the person who installs single-stage stuff.

 

[Rusty Fords]

older Honeywell Pro 8000 ( cant remember the new replacement # at this time) with a outdoor temp sensor is capable of doing a dual fuel system needed for the H/P without any additional components.

99LeCouch You are correct I have seen a lot installed incorrectly like a 5 ton unit on a 2 1/2 ton duct system, no fossil fuel kits 0n older installations ETC...

I know Good Techs/companies that put the customer first are hard to find. Take the time and do it right the first time.

 

[olds70supreme]

OK, second guy is coming on Friday to look and quote replacement.

The symptom I had been seeing was the breaker would trip when the AC was turned on.


First AC tech who came to quote swapped the capacitor for one he had with him - no change. He then pronounced the compressor dead but didn't explain why (I didn't think to ask until after he left).


The cooling fan spins freely.

Ohm readings on three terminals on the compressor (pin-to-pin) are...
3.1
32.5
35

All three pins measured open to the compressor body itself (not shorted to ground, correct)?

What do the ohm readings indicate?

What/how else should I test?

Thanks in advance.

 

[LS6 Tommy]

Ohm readings on three terminals on the compressor (pin-to-pin) are...
3.1
32.5
35

All three pins measured open to the compressor body itself (not shorted to ground, correct)?

What do the ohm readings indicate?

What/how else should I test?

Thanks in advance.

Did the compressor trip the breaker instantly, or did it hum and draw locked rotor amperage until the breaker tripped, say 10 seconds or so? Was the impedance done with the wires off the compressor terminals? They need to be off.

When you test single phase compressor impedance, the lowest number is the Common to Run winding, the Highest is Start to Run and the middle is Common to Start. The highest should be the sum of the two lower readings.

3.1 to Common is the Run winding.
32.5 to Start to Common.
35 is Start to Run.

None of the windings are "open". You already stated you did not indicate grounded windings. Since Start windings typically have three to five times the resistance of the Run winding, it looks like a wind-to-wind short on the run winding.

As others have said, you almost definitely have an R22 system, so the entire system will need replacement. A quality installation is more important than brand or grade level. Don't go nuts with a super high efficiency unit, especially anything Energy Star as they will never deliver the efficiency in the rating unless the entire house envelope is insulated and sealed to meet the Energy Star specs. Inverter units are very good.

Tommy

 

[yeldogt]

When single speed equipment is replacing single speed equipment -- the rebate drives the choice. Rebates normally eliminate the lower SEER units ... bumping up to the highest SEER single speeds don't typically have the pay back unless doing an odd system as the Bosch condenser with a new VS furnace ... or in areas with very high cooling loads. It's math in hot areas. The better stuff is very quiet.

Bumping up to multi speed is all about comfort ... they match load and eliminate humidity. Zoning with those equipment can also fix lots of bad ductwork problems that many houses have