Frequently Asked Questions (and answers) about how to Buy, Diagnose, Repair Air Conditioners & Heat Pumps:
These questions about air conditioning and heat pump systems help diagnose problems with those systems such as lost cooling, noises, condensate leaks, or failure of the equipment to start or stop running.
We include links to air conditioner & heat pump inspection, installation, diagnosis & repair article series explains in detail the inspection, troubleshooting diagnosis, and repair of all types of residential and light commercial central air conditioning and heat pump systems.
This article series describes how to inspect and repair all types of residential air conditioning systems (A/C systems). Information for home buyers, owners, and home inspectors about A/C or heat pump system problems. Page top image provided courtesy of Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ].
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?
at DIAGNOSTIC GUIDE A/C or HEAT PUMP - be sure to check the guidance given there.
On 2019-06-28 by (mod) - if I lower my thermostat more than 1 degree at a time unit stops cooling and temperature goes up
We need to be specific about the difference between the two cases of lowering by one degree or lowering by more than one degree on your thermostat. Is it that the a compressor motor turns off and one case and not in the other?On 2019-06-27 y billy
I have a carrier heat pump. if I lower my thermostat more than 1 degree at a time unit stops cooling and temperature goes up
On 2019-02-27 by (mod) - backup electric heat on pushes up COOLING costs
Thank you for an interesting question Gary.On 2019-02-27 by Gary
My daughter lives in a 3 year old apartment with two Heat Pumps mounted in the outside walls below her picture windows. One heat pump is in her small bedroom and the other one is in her living room/kitchen area and runs the most I believe.
Her electric bills the past two months have gone through the roof, I am wondering if one of the heat pumps might be the cause? If so, how might I diagnose the problem and determine which heat pump is the cause.
Details: It is mid-winter here in NJ but the temperatures have not been too bad, a mild winter, very little snow. During past winters, her electric bill has ranged around $30 to $50 max. per month. However, her last month's electric bill was $65 and her current electric bill jumped to $103! Her usage of her TV, lights, refrigerator and microwave remain constant and doesn't explain her much higher electric bills the last two months.
She keeps her Thermostats on each Heat Pump always set at 72 degrees. I just learned that heat pumps might have an electric back-up heater built into them that comes on when the outside temperatures drops too low for the main Heat Pump Function to operate well to give sufficient heat inside.
Might one of my daughter's heat pumps be malfunctioning resulting in higher usage of electricity and higher electric bills?
I can envision that if the main heat pump with its freon is not working or not working well, then the built-in back-up electric in the heat pump might be kicking in and doing all or most of the heating at a much higher cost
.
Is my theory correct and if so, how might I diagnose the heat pump to verify the problem before calling and paying for a Heating and Cooling Repair Company or bothering the landlord to do the same?
On 2017-07-01 by (mod) - heat pump won't turn off
RyanOn 2017-06-30 by Ryan
My water source heat pump is running water through it non stop. I replaced the rely and it is still doing it
On 2017-02-26 by (mod) - snyder general melted wires in combustion box
I don't know what to make of that comment but Watch out: if wires are melting in the control box for your heating or cooling equipment shut down the electrical circuit immediately as you risk a fire or shock.On 2017-02-26 by mike
snyder general melted wires in combustion box
On 2017-01-31 by (mod) - If your unit is running in heat mode and backup heat is on
TomOn 2017-01-31 by Tom
In the above unit 1 1/2 ton when run in the heat mode the fan will never stop running, in the A/C mode fan starts and stops with the outdoor init
On 2017-01-05 by (mod) - Goodman A24-10 that the heat strips are coming on even when the tstat is disconnected
For starters,On 2017-01-05 by Mkhunter810
I have a Goodman A24-10 that the heat strips are coming on even when the tstat is disconnected. I have replaced the sequencer and fan motor relay. The heat strips test as being good on a multimeter. Any idea what might be causing this?
On 2016-11-27 by Anonymous
I have a Frigidaire a.c./heat window unit 12000 but. I cannot turn the heat for low to high what could be the problem.
On 2016-01-21 by (mod) -
If the thermostat is being warmed by another source: heat output, sunlight, warm air currents in the wall, or if is defective we might see the condition you describe. After all the thermostat is only measuring the temperature at its own spot.
On 2016-01-21 by Anonymous
inside temp is set at 73 thermostat shows 73 but it feels like 62 in here help, please
On 2015-12-30 by (mod) -
It sounds as if you need an HVAC service technician who will probably check
1. the reversing valve and other controls that switch from cooling to heating nmoder
2. the operation of your back-up heat for this heat pump system: if outdoor temperatures are low.
On 2015-12-30 by Anno
I have a split unit that when I turn on the heat all it does it blows out cold air. I've check the thermostat and it does get 24v,the blower works,outside unit turns on and the fan is working. My question is what else could I check to try to fix the issue?
(Mar 7, 2014) Anonymous said:
im getting 102 deg heat and should be 115. I changed sequensor and relay and fuse link
(Mar 28, 2014)
DANIEL BILA said:
I HAVE 9 A/C BUT 3 I,TS BLOING THE HOT AIR THE OUT SIDE UNIT THE COMPRESSOR NOT WORKING SO ITS RUNING THE FAN MOTOR ....HALP ME TO SOLVE THE PROBLEM
(May 9, 2014) laurie said:
I have a Heil model number PH5036AKB4 ac/heat unit my problem is that it will run fine on heat no problems at all but on air it will blow cool air for about 30 mins if I'm lucky and then it just stops blowing
and then u have to cut it off and wait for it to want to work again which can take any where from a few hours to two or three days please help it's so hot and I have asthma what can I do to fix it Thanks so much
Anon, start by checking the fuse or circuit breaker;
Or further below at
Continue reading where you will find an ARTICLE INDEX choose the diagnostic procedure beginning with the article titled
LOST COOLING CAPACITY
Reply:
Please see the diagnostic advice at LOST COOLING CAPACITY and let me know if questions remainKevin Bresee said:
Hello,
I have a Rheem central air unit Model: UGDJ-05EAUER Serial: EB5D302F499606255. My dog months ago ate wires outside and blew the board, thermostat, and some fuses.
I had all fixed accept I just got a new thermostat and checked wiring and my problem is that the heater had worked but now that its hot the AC turns on all systems go but then it keeps shutting off and the new board is suppose to have a diagnostic light but tells me nothing.
Cold air comes out of registers, a little slower, I can see the blower motor spinning in unit/air handler and outside compressor is spinning and staying on even when the blower motor shuts off. I looked at the only capacitor inside where blower motor is and it is not swollen or anything but unable to check voltage.
Please help 98+ temps lately and cant afford service!
(May 30, 2014) Anonymous said:
I plugged my window air condoning 115 volt in 220 volt by mistake and I was not aware that the plug I have used was only only 220 volt I have in the house. the A/C went on then shut off by itself and It did not want to turn on again. the cable and the plug it is fine .
I checked the circuits brakes are fine too. What I should do now? thanks. Safwat
I'm mystified about how it was possible to plug a 115V appliance into a 220V electrical outlet: the wall plug connectors are quite different.
But if someone managed to do so, possibly by splicing on a 220V plug, the voltage could have damaged a control or circuit board in the device.
Check for an internal fuse blown in the AC unit. - Moderator
(June 6, 2014) Softwat said:
Probably overseas; plug adapters that only convert plug shape are common since most electronics' power supplies can accept 240v.
Reply from moderator:
No, Softwat, air conditioners do not use low-voltage power supplies such as the type you describe, and a system designed to run on 120V is not likely to enjoy being wired at double voltage.
(June 9, 2014) xenaon said:
i rent from a bad guy. He shut off the wall switch to a Rheem Criterion II furnace - which shut off the fan.
Before, if I turned on the wall switch - the fan went on if the AC was on. Now, it doesn't. Inside my apt the AC (2) and Furnace (f) breakers are fine. 3 hours later, the bully shut off the gas water tank downstairs - turning the red valve switch on the pipe to horizontal, then setting the control to off and "vacation" so the pilot light is no longer lit.
On the roof, there are 12 SEER 10 AC units for the central air for each unit.
The small white compartment box is open and it says UP/DOWN - that you can take the cartridge out to shut the AC unit off. Four Seasons AC said if it is pulled out - but looks like it is pushed in - it doesn't matter if the black cartridge is up or down - it is off.
BUT: they said the heat to the Rheem and the furnace fan should still go on even if the roof AC was off. The heat and the fan on the Rheem do not go on.
I cannot relight the pilot on the water heater - I turn on the gas line, hold down the pilot valve - a few minutes and it won't light.
I cannot find a way to turn on the Rheem Criterion II gas/AC unit. What else needs to be turned on? Thermostat (Honeywell) does not ignite the AC or fan or heat - but it could not possibly be the thermostat as the person who shut off the fan switch - also turned off the water heater.
Can anyone tell me how to get back on the furnace/AC in the closet - and did the bully per chance just take out the cartridge to the AC on the roof without worry of electric shock? If it is not pushed in - do people feel it is safe to just push it back in?
Four Seasons AC/Furnace said the AC circuit breakers are connected to the roof AC - and the furnace circuit breaker is connected to the closer furnace/AC.
CHeck that the equipment's power switches are ON including at the electrical panel, at the air handler (service switch), at the compressor/condenser (service switch).
Also check that the inspection doors to the air handler are closed securely and that there is no condensate pan flooded with water and thus tripping a condensate overflow pan switch.
Search InspectApedia for AIR CONDITIONER WON'T RUN for details.
(June 13, 2014) Scottie said:
I have a problem with my Central Air Unit and Furnace. Turned on Air this year and there seems to be a rythmic thumping noise you can hear from the AC line to the furnace.
You can feel it in the cold air (coolant) line to the furnace. What is this from? Air in the line? Does it need more coolant?
Any help is great
Scottie I'd like to help but just can't make a useful guess from must your note.
However take a look at our diagnostic article on types of air conditioning system noises to see if that points you in the right direction. See
inspectapedia.com/noise_diagnosis/HVAC_Noise_Diagnosis.php
6/22/2014 Mimi said:
My parents called me and said that the air conditioner was not working. I went over and check out unit outside and the coils were frozen.
I turned off the unit and I tried to trouble shoot to see we can get it going again. It said that I needed to clean the coils and get the dirt out, change the air filter if needed.
I did all that but then a couple of hours went by and it still wasn't cooling down the house.
The air was blowing fine but it was not very cool air.
So then I went into the garage and check out the coils inside and they were frozen too. I then went and shut off the unit and waited until the next day when everything was thawed out. I looked to see if the wiring was somehow damaged too and it wasn't.
I started it back up again and I will go back to see if it has cooled down. I'm thinking that it might need a charge of gas what do you think?
Can you please give me some advice, if we had the money for a service call I would have already called someone 2 days ago. Im worried because my parents are elderly and it's been getting pretty hot.Please help with some adive
Mimi,
the refrigerant gas in an air conditioning system does not normally need to be changed. Instead, let's diagnose the cause of coil icing such as a dirty air filter or a refrigerant leak.
See this diagnostic article on causes of coil icing and keep me posted
inspectapedia.com/aircond/Cooling_Coil_Frost_Ice.php
(June 22, 2014) Mimi said:
My parents called me and said that the air conditioner was not working. I went over and check out unit outside and the coils were frozen
.
I turned off the unit and I tried to trouble shoot to see we can get it going again. It said that I needed to clean the coils and get the dirt out, change the air filter if needed. I did all that but then a couple of hours went by and it still wasn't cooling down the house. The air was blowing fine but it was not very cool air.
So then I went into the garage and check out the coils inside and they were frozen too. I then went and shut off the unit and waited until the next day when everything was thawed out. I looked to see if the wiring was somehow damaged too and it wasn't.
I started it back up again and I will go back to see if it has cooled down. I'm thinking that it might need a charge of gas what do you think?
Can you please give me some advice, if we had the money for a service call I would have already called someone 2 days ago. Im worried because my parents are elderly and it's been getting pretty hot.Please help with some adive
(June 24, 2014) Anonymous said:
Air handler started blowing hot air while in AC mode. temp was set to 77 OAT was 76 but very humid, turned unit off and waited until morning. Turned unit on and it was blowing cold air again. Unit worked for rest of weekend.
Call a service tech, everything checked out ok except for low refrigerant and superheat/supercool spread was a little off.
Unit again started blowing hot air last night at 11pm, again a very hot humid day. Is this a compressor starting to fail?
Anon that operation may be normal depending on the thermostat set point, outdoor temperature, and building heat gain.
If you think the system has lost cooling capacity see LOST COOLING CAPACITY in the links further below Continue reading you will find
an ARTICLE INDEX to see diagnostic procedures
Cindy see these HVAC data tag decoding guides
inspectapedia.com/aircond/Data-Tag-Decoder-Air-Conditioner-Heat-Pump.php
For York- Borg Warner air conditioners take a look at the outdoor compressor/condenser unit's data tag (don't wipe it or you'll wipe off the lettering).
The encoding of cooling capacity varies by equipment type and year.
On some the first two digits of the model number are MBTUs, so for example if you see
DWR 20 XXXX that's a 20,000 BTUH unit (two tons) of cooling capacity
Other model numbers encode the cooling capacity in the 6th and 7th positions, EG:
H1CB012506 - is a 12,000 btuh unit.
For models with this format
D-95A 30 N 080 06-A
The BTUH is in the position after the N - our example shows 080 or 80,000 BTUH
See Carson Dunlop Associates' Technical Reference Guide (cited in these articles) for full details.
(July 1, 2014)
cindy said:
my model is gva027 and serial number is efds166414, could you tell me how many btu's it is?
Reply:
Looks like this is a heat pump (the "E")
16,000 BTUH (using the 5th & 6th digits)
Check the owners' manual that should also give you a proper decoding key for your unit. Let me know if your manual says something different.
(July 1, 2014) Robert Wheeler said:
I replaced the contactor, the capacitor, the time delay relay inside the AC unit and the furnace 24V transformer which blew out because I didn't turn off the furnace switch at the breaker before changing the contactor and capacitor.
I even by-pass the thermostat by connecting the red and green wires to see if it would come on, which would tell me if my thermostat was bad or not. After all that it still only comes on when I press and hold down the contactor.
Robert, did you connect the thermostat wires at the thermostat or at the other end, at the AC control?
Did you check for obvious burn or overheat marks on components like relays or circuit boards?
(July 5, 2014) Robert Wheeler said:
Hi Dan - Thanks for replying....I connected the wires at the thermostat. Also, today I replaced the circuit board with a new one and I still am not getting the AC to run without holding down the contactor.
(July 5, 2014) Robert Wheeler said:
It was the furnace circuit board that I replaced today. I replaced it thinking it may have gone bad after I accidentally blew the 24V transformer that connects to it.
Reply:
Robert,
Thanks for the follow-up. Your diagnosis and repair will certainly assist others.
I'll keep the remarks and at future edit move them into an appropriate permanent spot.
Connecting the wires at the thermostat is simulating a thermostat calling for the equipment to run but doesn't rule out a short elsewhere between those wires.
(July 7, 2014) jkwinans said:
How can I figure out if I need to replace my AC unit on my camping trailer or if it is only a thermostat issue? Often when I get to the camper the air starts immediately, but when it reaches temperature it will not restart. This week-end it ran perfectly until I was almost ready to leave..... now it does not re-start again!!! Is it possible for an old lady to diagnose this or do I need a repair person?
(July 7, 2014) jkwinans said:
I should also add that neither the fan or heat will kick in either at least by using the control panel on the Coleman thermostat.
JK
This is pretty easy. Just go to the end of the thermostat wires where they appear AT THE COOLING UNIT controller.
There if you jump the two thermostat connections, that's exactly the same as if the thermostat had called for cooling.
If the system responds normally then the problem is indeed in the thermostat or in the thermostat wires.
(July 7, 2014) jkwinans said:
Thanks for your advice. Since the cooling unit is on the roof I will need to wait until I can get someone to climb up there. LOL do you guys hire out?
Seriously, I appreciate your help.
Reply:
(July 8, 2014) (mod) said:
Keep us posted JK. And no, seriously we don't hire out - it would be a conflict of interest with that of InspectApedia's role in providing information not connected to other business activities.
(July 9, 2014) Rick Storm said:
My outdoor compressor fan sometimes shuts off or will not start.My AC repair guy said the fan motor is getting too hot and shuts down but even on a cool night or rain it will do the same thing .Is there a switch or capacitor that may need replacing?or could it be the thermostat?Thank You
(July 9, 2014) (mod) said:
Andre Matthew said:
My Ac does not cooling properly, and it drops cooling after half an hour.
(July 13, 2014) Christine Midkiff said:
We just had a Frigidaire HVAC/Heat Pump installed. Every time the unit reaches the programmed temperature and shuts off, it immediately tries to restart for a second or two, then shuts off. It does come back on when it is supposed to.
Any ideas as to why it keeps trying to restart?
(July 20, 2014) Larry said:
I purchased a slightly used 2.5 ton R-22 heat pump to replace my 10 yr old a/c condenser unit. The "new" unit is pressurized but I don't know if the R-22 was pumped down into the condenser or was reclaimed and filled with inert gas.
Is there a way to determine without losing the R-22? Would a non operating condenser filled with some amount of R-22 show about 120 psi at 78 degrees F? I have tried locating the original installer but have had no success. Worst case, I will recycle whatever is in it and refill with virgin R-22.
(July 27, 2014) Anonymous said:
I bumped into the outside compressor and saw sparks fly, but the motor continued to run so I thought no more about it other than planning to inspect inside the unit for a loose wire.
The AC was no longer cooling however and I took off the door and found that a screw (probably from an earlier repair) had rolled over onto one of the connectors on the run capacitor.
The capacitor looked like it had been in a fire (smokey).
The compressor fan will no longer run. I assume the capacitor needs replacing. My question though is, how did the fan (not the compressor) continue to run just after the sparks flew, but will not run now?
JDStevens
Sorry! Forgot to mention the compressor no longer works also. Also assume that when the capacitor problem is fixed, both problems will be fixed.
(July 27, 2014) Anonymous said:
At first, I thought the "fried" cap was the start cap, but its specs boast only 5 MFD and is oval shaped.
The other cap is cylindrical and its label has 80 MFD which has to be the start cap? It's a little confusing as I thought the run cap would have to remain closed to complete the circuit ..
perhaps it did until as you indicated, on the next cycle it wouldn't close again. Yes, the fan was spinning when the short circuit occurred.
I will probably replace both caps since they aren't very expensive. Currently, I have all power going to the unit turned off. I tried all day to find the capacitors, but no one that sells them is open on Sunday.
Home Depot, Lowe's, Ace, TrueValue don't stock them.
I checked the unit and its schematic for a local fuse, but found none and no mention on the schematic.
(Aug 19, 2014) Miles C. said:
I bought a home and during the purchase the heat pump was replaced with a new AC unit
HUD says if it had done the repair I would find paperwork
How can I back track the unit to see who bought it? (Installed it)
The heat pump already installed could have been repaired
Now before winter I need to replace this new AC unit with a heat pump
Miles
It sounds as if someone took a shortcut (cheaper to install air conditioner than a heat pump) or was just mistaken.
Your AC compressor unit will include a data tag with brand, model and serial number.
Most likely there are not so many installers in your area that you couldn't just give them a call to ask who installed the unit at your address. Start by asking each company if they install the brand you have. If they do, then ask if they installed yours.
Also, if an installation and operating manual was left behind (as it should have been) there may be a note with it on the installation date.
Keep us posted.
aircon maintenance said:
Tips to maintain your own air condition in home and in office.
There are things you must know on how to maintain air condition without the need of technician. Simple steps to fix it and if there is a major problem then you need to hire aircon services
(Aug 30, 2014) Anonymous said:
A snowflake appears in the upper left hand corner of the thermosat and the ac unit doesn't work
(Sept 3, 2014) dan said:
I have a new unit 3 ton ac ,,the evap and cond was replaced ,,new line set ,duct was replaced ,I get 70 psi on low side and 200-210 on high side ,temp coming out of duct is 74-76 and return is 79-80,furnace seems to be blowning a lot of air ,
I took side cover of coil off and lower to mid is temp of 56 but mid to upper coil is 72 degree,,the outside fan has 114 degree air coming out of it ,,the low pressure line on out side unit seems to be 88 degree
(Sept 11, 2014) Carol said:
Our AC system is making an odd noise. It is coming from just behind where the filter sits, it is a loud, continuous, rhythmic like sound. The sounds is like a cross between a knocking and a drip. I left the house at 10:30 am and it was not making that sound. Both thermostats (up and down) stairs were set to off when I left. When I cam home at 3:30pm it was making that noise and it has not stopped. What in the world is it?
(Sept 28, 2014) sjmwhit said:
In August of 2013 my 4-ton Trane heat pump stopped working. The repairman replaced the capacitor. Four days later he replaced the outside heat pump condensing unit because the compressor went out. To save on the cost he recaptured the R22 and put it in the new American Standard dry compressor.
He started it up and it sounded ok and was putting out cool air. After he left I started hearing a high pitch whining noise coming inside the house from the outside unit.
When the unit came on it would run for 5 minutes smoothly and quietly and then the noise would start and get louder until the unit shut down after 15 to 20 minutes. The repairman said it was vibration and put 4 rubber pads under each corner of the unit. The noise continued.
In July of 2014 I called the American Standard Help Line and they selected a local repairman to come out and check the unit. He said it was a bad compressor so American Standard paid him to replace it with new R22. The noise is now louder than before and loudest on 90+degree days
It also makes the noise in the winter months and runs 50% of the time on auxiliary.
My repairman has disappeared. American Standard has refused to do any thing else because they now say my repairman failed to register the unit for warranty and the selected repairman who said it was the new compressor simply says he doesn't know the cause of the noise. I need help. Does anyone have an answer?
(Oct 12, 2014) Steve said:
Goodman ac/heater control board replaced due to being fried by lightning storm. Will not turn on. Has power. Indicator light on board has not flashed.
(Oct 12, 2014) Steve said:
Goodman ac/heater model gmh80804bn.
Control board replaced when it was fried by lightning storm.
Has power but will not turn on. Indicator light did not flash or come on after instalation.
Rachel
If your thermostat is set to HEAT mode and the room temperature is below the thermostat set temperature then I suspect your system has a control or wiring problem and is not switching to heating mode or equally possible it switches to heating mode but low outdoor temperatures are calling for use of your backup heat source and that's what is not working.
As you replaced a control board someone also suspected a control problem.
A check of voltages on output control circuits from the control board can tell you if that component is calling for heat. Proceed from there to check the backup heating system components .
(Jan 24, 2015) Anonymous said:
heat nor air will come on after setting thermostat
Jan 24, 2015) Anonymous said:
My air handler relay is making a humming noise when it is off (not heating or cooling). The unit does work.
AUTHOR:Daniel (no email)
COMMENT:
my goodman 3 ton ac unit had a full drain pan tonight. I drained the pan with my shop vac then cleaned the condensate pipe with my shop vac, vinegar solution and a bit of internal scrubbing. All is dry and looking good now.....
EXCEPT!
a few inches 10? behind what I assume is the automatic shutoff trigger attached to the drain pan that makes the ac unit stop (but not the blower) - behind this shutoff, I see two exposed wires!!! a red and a black...
with copper ends (little thread looking copper not the thick single wire type) sitting in the drain pan! Is this OK?
Do I need to some how crawl back there and find out what they were supposed to be attached to, or are they part of the auto-shutoff mechanism and I don't need to panic?!?! Thanks for your help!
daniel@laustintranslation.com
Brandon,
If your air conditioner or heat pump system is not working, start
at LOST COOLING CAPACITY for help in diagnosing and repairing the trouble.
That article begins at
inspectapedia.com/aircond/Air_Conditioner_Diagnosis.htm
I suspect that the compressor condenser is not running or there's a refrigerant problem or the thermostat control is not switched to COOL mode.
(May 28, 2015) Gloria said:
Will a TurboAir condenser operate one TurboAir air handler and two Fujitsu air handlers?
(May 28, 2015) Gloria said:
Is there an interface card to facilitate communication between a TurboAir condenser and a Fujitsu air handler?
(May 30, 2015) dallas said:
ac unit freezes up ice forms on radeaitor
Anonymous (no email)
COMMENT: Fin work. But no coolAir. rooftop a c
(June 3, 2015) Anonymous said:
410a system not cooling,high presure 310 low presure 150
(May 30, 2015) dallas said:
ac unit freezes up ice forms on radeaitor
(June 8, 2015) Don said:
My air conditioner is not keeping house cool enough. There is ice formed on the connection from the house to the outside unit. What is the cause of this and likely repair?
(june 19, 2015) craig said:
Does anyone have a wiring diagram for a 1978 vintage magic chef hvac (heating & air conditioning unit), model # possibly "apt 403-1" or model g66-100d-1? No wiring diagram anywhere inside/on unit. No circuit board. 4 wire thermostat board with 24 volt transformer, relay (black box) and honeywell heat sensing unit (3 wire, red, blue black).
102 vac heater unit, 240 vac 60 amp a.C. Compressor, single speed blower motor.
(July 1, 2015) Anonymous said:
The compressor starts and stops.
(July 4, 2015) E MAN said:
I am trying to figure out why my central air unit makes humming/vibrating sound when it's on. The strange thing is that when I open the door to where the HVAC unit is located, the sound completely stops. When it's closed, the sounds return (I had my wife tell me whether there was noise or not as I opened and closed the door)
. Right on point, opened door equaled no noise and closed equaled noise returning.
What is causing this issue?
At first, I thought it was the filter (correct size, I confirmed), but it's not.
Any advice would be greatly appreciated!
E Man
If the equipment keeps running and the humming stops when you open an access door to the air handler that suggests
1. that your system is unsafe since there should be a door interlock safety switch to avoid someone reaching into moving parts and chopping off an arm
2. something in the door itself may be vibrating
or
3. the system is return-air starved, possibly affecting air movement through the unit, blower fan behaviour, or plenuim wall vibration
Be careful - you can get an arm or finger cut off.
(July 9, 2015) Anonymous said:
I have a LG LSN090HE ductless AC/Heat pump in my garage and whenever the power goes out it won't come back on. It is supposed to have a 3-minute 'overload' timer of some sort...but it never allows the unit to come back on.
I have to go to the outside unit, pull the main power, and disconnect all the electrical lines to the PCB then let it sit for HOURS...and it MIGHT then come back on. In this no-start condition there is an audible clicking from the outside unit anytime it has power.
If I pull the power the clicking stops...and if it starts again after I let it sit I know the unit wont start again.
(july 10, 2015) francis franqui said:
I have an a/c and need to find the brand of it; the product id is 25hba336a0030010.
How can I find which is the manufacturer of it?
Whitey
I have not found any U.S. Federal regulation that tells a private homeowner what thermostat settings are required. In my opinion, BALDERSASH!
There are federal guidelines for the workplace: in the workplace the minimum temperature for indoor workplaces is 68 degrees F, maximum is 76 degrees F.
The acceptable range for indoor humidity is between 20 and 60 percent. Source: U.S. DOL & OSHA & ASHRAE 1975.
Tom said:
I have an older technician says Goodman air conditioner and label is unreadable. Numbers given by technician MLE25-1 890501092. I need to located the model number for unit. These numbers do not register with Goodman in their database. Label is on unit but weathered.any assistance on how th locate other numbers around unit internally etc. to get model number? On coil or in frame work? thanks Tom.
16 July 2015 Filters and A/C external Static Pressure said:
I have A/C Fan with 2.5” wg Static pressure and have two filters to put in the way MERV 16 and prefilter. the duct to the area is no longer than 15 ft. Is that Static pressure enough to have these two filters in the way.
Thank you
Filters:
According to Brendon Reid's nice article on this
Filters
If you are really quoting a properly-made HVAC duct system static pressure measurement in inches of water column " wc then your number is a bit shocking. Most residential blowers won't create more than 0.9" wc. Your number sounds high, wrong, and likely to mean that the system is noisy and also return-air starved.
Typically we want to see 0.5 wc static pressure as a general rule of thumb. - see www.achrnews.com/articles/103710-interpreting-duct-static-pressure
- Brendan Reid is President of the Comfort Institute (CI), Bellingham, Wash. CI provides building science training and instruments for whole-house and air-distribution diagnostics and repair
He can be reached at 360-420-5049
For photographs of these various air conditioning and heat pump parts, and for an explanation of where these air conditioning components are physically located,
see A/C or HEAT PUMP COMPONENTS which discusses and helps you name and recognize various Indoor A/C Components and Outdoor A/C Components
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