HVAC heating, ventilation, air conditioning & refrigeration system component identification FAQs:

Frequently-asked questions on how to find & identify the components or parts of an air conditioning or heat pump system, including indoor and outdoor equipment.

This article lists and explains the function of the basic components of an air conditioning or heat pump systems and provides detailed inspection, diagnostic, and repair advice. We include photographs to assist readers inrecognizing cooling system defects.

FAQs on Air Conditioning & Heat Pump Components

 

These questions & answers about the components in an air conditioning or heat pump system were posted originally

at AIR CONDITIONER COMPONENT PARTS - be sure to see that article.

Question: I have been cautioned to stay clear of variable-speed blower options

(Mar 14, 2014) Phil said:
I'm in the market for a replacement electric/gas pack unit. I have been cautioned to stay clear of variable-speed blower options and their sophisticated electronic controls for lack of durability. The reason given was sensitivity to power fluctuations - drop-outs and surges.

Likewise, that copper/aluminum fin condenser coils of today are more leak prone than their all-aluminum cousins. Do you agree and if so could you recommend some 13-seer models for their use of more durable/reliable components? Or, help me know what to look for? Thanks for your expertise and help cutting through the marketing confusion!

Reply:

Thanks for the "expertise" compliment Phil but with a little embarrassment, this question is beyond our expertise. While your surmise sounds sensible, in fact across thousands of readers and comments, I have not seen a particular pattern indicating that variable speed blowers fail more frequently than their simpler single speed units. Indeed for systems providing both heating and cooling we generally want a blower capable of operating at at least two different speeds for the two different modes.

I suspect that power fluctuations are more of a worry for controlling circuit boards in general.

Back in 2009, in "Comparing Motor Technologies", achrnews.com Brian Michael reported that constant torque motors, a comparatively new design in use in HVAC systems (dating from a Regal-Beloit (General Electric) design in 2006) offered high efficiency that helps meet the 13-SEER HVAC models in your question. That article does not cite the concerns you raise.

Question: what is meant by "high side" and "low side" on an air conditioner or heat pump system?

(July 23, 2014) Anonymous said:
sometimes they say high side and low side is this referring to high pressure and low pressure?

Reply:

Yes

High side pressure is on the compressor outlet side and low side pressure is on the compressor suction side. On the outlet side of the AC or heat pump compressor the refrigerant is at high pressure (over 100 psi) while on the suction side the refrigerant pressures are quite low.

See REFRIGERANT PRESSURE READINGS & CHARTS for details.

Question: problem with the unit blowing hot air

(Aug 28, 2014) donrebich said:
Question: We began having a problem with the unit blowing hot air and going outside to the unit finding the fan not working but after hitting a red button the unit came on and functioned properly. Calling a service co and detailing what had transpired he claimed it was the fan motor.

Another tech came out and claimed the system had excess frion, the high pressure side was at 280 and suction was 75 on the compressor. Being extreamly hot outside, perhaps causing either the fan motor to kick the system off or a pressure swithch.

Reply:

See the diagnostics beginning at AIR CONDITIONING & HEAT PUMP SYSTEMS - home

 

Question: can you repair a defective air conditioner compressor?

(Mar 4, 2015) Rick Regaspi said:
May I ask if the defective compressor motor of Air-con can be repaired? or is there any repair shop for compressor motor?

Reply:

Rick: residential HVAC compressor motors are typically a sealed unit that cannot be field-repaired.

 

Question: split system is not cooling and not dehumidfying well and it squeals

(May 3, 2015) Robert said:
My split system is not dehumidifying the air and is not cooling very well. There is also a squealing sound when the unit turns on and a lot of noise in the cabinet where the A-coils are when the unit is turned off.
The copper line that is not insulated is cold rather than warm like it usually is.
Could there be a leak or might the A-coils need to be cleaned?

Reply:

Robert
I would investigate the squealing first - look for a failing blower assembly, belt, or in a split system, more likely a motor.

 

On 2020-10-20 by pete

I have a Trane heat pump similar to model XV20i. The unit is located about 4 feet from stairs leading into my home. When it snows, air from the unit blows snow onto my steps. Is there something I can use not to block the air flow but to direct it downwards? I just need it on the one side facing the steps.

On 2020-10-20 - by (mod) -

Pete

I can't be confident of offering an answer to this problem as I don't have the full picture, but in general, a modest deflection of exhaust from the condenser unit may be ok provided you're confident that you are not so obstructing the air flow as to prevent the unit from operating properly. Start by looking at the specific clearance distances given by the manufacturer of your Trane unit - in the IO manual for your unit.

Also see CLEARANCE DISTANCE, HVAC https://inspectapedia.com/aircond/HVAC_Clearance_Distances.php

On 2016-06-20 by grover

can I get a wiring diagram of 18000 btu 220v teco mod# LA1875BFS window unit.capacitors taken off,5 wires loose

On 2016-06-20 - by (mod) - contact Teco in Australia

Sure Grover, directly from the manufacturer, Teco, who produces various HVAC equipment in Australia.

Teco's window AC units are described at http://www.teco.com.au/room-air-conditioners

In Sydney contact
TECO Australia Pty Limited
335-337 Woodpark Road,
Smithfield NSW 2164
Tel: 61 2 9765 8118
Fax: 61 2 9765 8185
Email: sales@teco.com.au

The company has offices in other major Australian cites as well.

For spare parts contact Teco at http://www.teco.com.au/service-enquiry - or call them at 1300 660 037 for parts and wiring diagrams, Australia-wide

On 2015-06-27 by Darren

I a so happy I can read this stuff and now know what I need. I have a GE Ambassador Mark 2 Furnace. While putting in a new hot water heater the check valve caught my Cooling coil and it snapped off from the furnace.

All the Freon leaked out. I attempted to solder this back together which I did but there is a leak.

The coil is 1/4 inch and I still have the original brass fitting but it looks like the tube snapped inside the male part still attache to the furnace.

I need that part so I can fix it. A new coil would be expensive and a new furnace even more. I need help ;locating a new fitting for the cooling coil.

Can someone help me please?
Thank you kindly,
Darren
dst.ledger@hotmail.com

by (mod) -

Darren

You can buy HVAC fittings and parts from your local HVAC supplier but for the case you describe I'm doubtful that you can do this correctly without hiring a service technician.

We do not *solder* air conditioning refrigerant lines, we use a higher temperature and stronger silver solder or brazing process. Furthermore making such a repair will cause formation of contaminants inside the tubing so that a cleaning procedure and installation of a filter/drier on the refrigerant piping will be needed as well as the proper refrigerant charge.

by Darren

Dan, I had someone out and he said that it would need to be brazed as you indicated. Wow..one mistake and now my expenses just went up and money is tight. I am trying to locate the parts so I can buy them myself and then have the repair. Its frustrating because i cant locate the exact part for my furnace.

I tired but with little luck. i am not the expert as you can tell but was hoping there would be a better solution. At $95 an hour I worry about a huge bill. Thanks for your help though and suggestion.

On 2015-06-16 by Howard - Is the refrigerant itself considered a component or part of the a/c system?

Is the refrigerant itself considered a component or part of the a/c system?

by (mod) -

We're talking opinion and lacking grammar and syntax, Howard.

An AC unit won't work without refrigerant, but refrigerant is a gas, not a physical mechanical or electrical component. It's not a "supply" in that refrigerant is not consumed - it recycles through the system.

In sum to make a useful answer one would have to agree on a definition of component. For example, an automobile engine will not work (at least not more than about a minute) without lubricating oil. Is the oil a component?

Merriam Webster gives this too-brief definition of "Component"

Full Definition of COMPONENT

1 constituent part : ingredient

On 2012-09-08 by Pete H

When the a/c kicks on, is the fan on the outside condenser supposed to come on right away, or does itcome on a few minuets later

On 2012-09-08 by (mod) -

Pete,
The behavior you describe is normal for some AC / heat pump systems. As long ad the fan continues to run, is not making an unusual noise like humming or rattling you should be ok.

On 2012-09-02 by vinson

water leakes from the bottom of in door ac/heater , still cooling but water runs from the coners down on the floor about a half gallon in 2 hrs.in fast drips when starting and at the end, when blower shuts off

On 2012-09-08 1 by (mod) -

Vinson, check for a blocked condensate drain

On 2012-07-07 by Jim Grammas

large ball of ice around the low pressure line at the plenum, water on floor, weak air flow through registers

On 2012-07-07 by (mod) -

Jim,

Weak air flow sounds like a coil frost blockage problem. Temp fix that is also diagnostic is to turn the system off for a few hours to let all the ice melt.

If airflow rate is back to normal the coil was ice blocked - that still needs diagnosis and repair. Replace any dirty air filters and ask the tech if s/he agrees to check for a loss of refrigerant or a refrigerant metering device problem.

On 2012-06-05 by Rickey

My AC is rated at 8.5 ampere. But now it is consuming up to 13 amperes of current. Due to this stabilizer gets overheated within 1 hour. please tell me about the defects.

On 2012-06-05 by (mod) -

Rickey, several problems can cause high current draw at an A/C system; some high current is normal at motor start-up at the compressor/condenser unit, for example. But if the run current is abnormally high, I'd suspect that the comopressor is binding, or there is a refrigerant metering valve control problem causing high head pressure.

On 2012-05-27 by matt

i cant get my outside unit to work checked all wiring and fuses the only thing i cant find is
the reset pressure button according to the schematics its optional on my unit

On 2012-05-29 by (mod) -

Matt, some fan motors may incorporate a reset button, or you may be talking about a different reset switch for the whole unit - it'd be described in the operating manual for the unit and is model dependent.

There are other failures, such as a bad contactor relay, that can prevent the outside unit from starting.

On 2011-09-28 by Bryan

Our central air system has been working fine all summer. It has 2 zone, upstair and down. WHen the down stairs thermostat call for cool air, the upstairs zone gets most of the air flow. This causes the system to run for a long time dropping the upper zone to be cooler than set for and the lower zone never reaches set temp?

Is there something I can fix or should I wait for the spring service to have this addressed being less than a month of the season left?

On 2011-10-03 by (mod) -

Bryan if you have a single air handler feeding both zones, and if too much air is blowing out of one of them, you should be able to find or if necessary install a balancing damper in the ductwork. By partly closing the damper in the "too cool" zone, you will force more air into the other zone.

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Continue reading at AIR CONDITIONER COMPONENT PARTS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• A/C INSPECTION CHECKLIST - OUTDOOR UNIT
• AIR CONDITIONING & HEAT PUMP SYSTEMS - home

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AIR CONDITIONER / HEAT PUMP COMPONENT FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS

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