Air Conditioner & Heat Pump Troubleshooting FAQs

Repair vs replace the compressor/condenser unit

A/C Heat Pump Compressor / Condenser Unit Repair vs Replacement FAQs

Because Q&A on this topic often involves decisions about replacing components in either or both the indoor and outdoor A/C or heat pump equipment you may want to see both the Q&A just below and also

AIR HANDLER BLOWER UNIT REPAIR vs REPLACE FAQs - replace the evaporator coil, replace the whole unit?

Replace Seized Compressor & AHU Coil or Replace Whole Units?

Need some help in deciding what to do with seized-up compressor (replace just the compressor and the coil at the air handler or replace the entire condensor/compressor unit along with new coils in the air handler).

Current system is a 3-ton 10SEER unit with Copelant scroll compressor & R22 refrigerant

If I replace just the compressor & coils (to equivalent parts), but charge it with R410A refrigerant, would it still be compatible with the existing condensor? Is it typical to replace the TXV (or TEV) valve when replacing the air handler coils?

Contractors are pushing towards replacing the entire condenser/compressor & coils (at a significantly higher cost). On 2011-08-06 by TN-Goose

by (mod) - when a compressor trips the CB immediately on turn-on

TN, when a compressor trips the CB immediately on turn-on, there is a short somewhere, or the motor is shorting out or drawing very high amps at startup. That's what your tech found and it's consistent with a seized compressor motor.

Your ductwork indoors at the air handler doesn't sound like a source of compressors blowing a circuit breaker.

And what the tech said about R22 no longer in use is quite correct. You'd either go to R410A which works similarly to the old refrigerant but not precisely the same, or ...

On replacing a seized-up compressor, if the new compressor is matched to the rest of the system one wouldn't necessarily think about changing rest of the system components.

However because the new compressor will also use a new refrigerant, the installer may want to compatible key components throughout: the condensing coil, evaporator coil, and refrigerant metering device (TEV), possibly other controls all to work properly with the new refrigerant.

By the time you pay for the labor to R&R coils indoors and outside as well as other parts, you can understand why the HVAC company wants to install everything new - it may be less labor, faster installation, and perhaps even more profitable.

Followup by TN-Goose: short circuit in compressor motor

Had Service tech check out my 3-ton compressor, which has been tripping the breaker immediatly upon turning ON.

Tech checked the resistnace of compressor terminals and noted that it has a short-circuit.

Says the cause of compressor short-circuit can be caused by rapid power ON-OFF from storms, and/or undersized duct diameter in the blower of the air handler in the attic.

My duct size is 14" on one side and 16" on the other side of the air handler.

Is there any truth in 14" diameter duct causing a 3-ton scroll compressor to seize-up/short-out?

Tech also it's illegal to recharge with R22 refrigerant; must use R410A. Is this true?

Reply by (mod)

OPINION: duct design defects might make the whole A/C or heat pump system run longer to satisfy the thermostat but it'd be a big leap from that problem to claiming that the indoor duct system caused the outdoor compressor motor to seize.

Other problems can kill a compressor motor, such as liquid slugging, over-charging, or refrigerant oil return problems.

And yes, R22 refrigerant is no longer permitted in A/C repair or installation.

While your system might run acceptably with R410A it's not designed for it.

Our A/C Compressor is completely shot. Is the replacement cost reasonable?

My central air tripped the breakers and I swithched it back on. It worked for one night and tripped again the following morning. Now cold air wouldn't come out so I called a tech. He was testing the compressor with a booster(?) and a pop sounded and tripped the entire house of electricity.

We had re set the main fuse box and he later said the compressor is completely shot.

We have a 3.5 ton condenser and he quoted me $1500 for just the compressor with a warranty of 6 months and recommended the entire condenser to be replaced since the warranty would last 5 years. Are the prices and what would be your suggestion? On 2011-08-28 by Jeremy -

Reply by (mod) - AC unit trips breakers

Jeremy an A/ C unit that trips breakers is probably drawing too much current - a sign of a hard starting or seizing compressor.

So what your tech says sounds credible.

The price sounds low for New York and normal for some other areas.

Do we replace a bad compressor or the whole condenser unit?

If either the compressor or condenser is bad, must they both be replaced? On 2016-06-29 by Tishtash

Reply by (mod) -

Tish

The compressor is the motor that is compressing suction-side low-pressure refrigerant gas into a high pressure gas. The outlet from the compressor flows through a condensing coil - looks a bit like a car radiator with fins and tubing. A fan blows outdoor air across the coil to cool it.

That causes the high pressure high temperature gas to cool back to a liquid refrigerant state, and in the process of removing that heat from the refrigerant we're in effect moving heat from the building interior to outdoors.

Now if just the compressor motor has failed, that's a replaceable unit.

If just the condensing coil has failed - say by corrosion and leakage, that's a replaceable unit.

If just the fan or fan motor has failed, that's a replaceable unit.

The whole outdoor assembly is referred-to as the "Compressor/Condenser Unit".

The decision to replace the whole compressor/condenser unit versus replacing one or more of its parts would turn on several points:

- what's the age of the unit?

- is the exiting unit using a no-longer available refrigerant?

- what will be the total cost to repair individual failed components with the total installed-cost to replace the whole compessor/condenser unit?

Signs of a Failed A/C compressor motor

Have an 11 year old compressor/fan unit that kicked off the breakers and now will not run at all. Replaced the capacitor, still no soap, although it is not kicking off the breaker now. Checked the fan motor for a reset button, and there isn't one. Any suggestions short of calling the serviceman? On 2011-08-22 by Jeff Huston

by (mod) - sounds like a bad compressor or other motor

Jeff:

I'm sorry to say you needed to call an HVACR tech. It sounds like a bad compressor or other motor that has failed.

It could be an electrical short - a short circuit might trip the breaker but also burn the wire enough that when you turn power back on there is no actual electrical connection - the circuit has become "open".

Replacement outside compressor/condenser for an R-22 system?

My outdoor unit was stolen this week wires cut and whole unit taken off concrete slab. Problem now is that unit was installed just 2 years ago.

The inside the house part of the unit is quite old but runs perfectly well. Our electric bills are very reasonable and we are also running a swim pool pump.

Cant I still replace just the outside portion even though the inside unit is refridgerant rated 22-r.

Cant I still find a unit for the outside that will support that and at the same time if the inside unit goes out I would only need to replace it as the new outside unit could handle a new inside unit.

I hope this makes sense as money is a big factor right now for this unexpected loss. Bottem line I can only afford the expense of replacing the outside unit if that is possible. On 2011-07-12 by nancy wood

by (mod) -

Nancy, your HVAC tech might be able to install equipment that uses R410 refrigerant to replace R22, but take a look at the refrigerant discussion in the article linked to at page bottom ARTICLE INDEXand titled REFRIGERANTS

Blower runs, no cool air delivered: do I need a new compressor unit and a new indoor air handler system?

My AC system stopped working this evening. The blower was still working but no cool air circulating.

I checked the outside system compressor/housing and found ice build up on the tube running from the compressor to the house.

The unit is almost 14 years old, and we've had nothing but 90+ temps for the past two months.

Is it just time to purchase a new outside compressor unit and a new inside AC coil unit.

My neighbor just replaced his at a cost of $7,700. On 2011-08-09 by Bill in VA

by (mod) - check & diagnose the problem before replacing an air conditioner

Bill, before springing for a completely new air conditioning system, I'd ask for some diagnostics on the present one. Your old system might need simply a control replacement or a refrigerant leak repaired.