Swede Loc: Trail, BC Canada

Okay still not working correctly, set to cool at 70, 70 showed up, compressor kicked in, been running now for 15+ minutes, registers kicking out cold air, thermostat still at 70. Moved “Cool At” to 71, the temperature gauge quickly changed to 71 and the system shuts down. Then I moved the thermostat back to our programmed settings of 70, thermostat still reads 70, and then the compressor kicks in again and won’t kick out even when it’s at 70 degrees-20 minutes now


:( :( Swede

singleviking Loc: Lake Sebu Eco Park, Philippines

First off, there's a 2 degree variable for thermostats in most cases. Since the compressor shuts off when the thermostat is set above your programmed temp and manually set to 72 degrees, it's not something related to your thermostat but might be related to the program mode it's set to.
My suggestion is to reprogram the scheduled temps and times for each day and see if this resolves the issue. You can also set your thermostat to "MANUAL MODE" instead of "PROGRAMMED MODE" and set the temp. This will bypass the your program and maintain a constant temp that is set.

If all of this fails, then call the A/C company that installed the system and ask for a technician to come and check it out as something is wrong.

Sorry for your inconvenience. This system sounds like it's relatively new and may still be under warranty. Many new systems now have 5 year warrantees.

singleviking Loc: Lake Sebu Eco Park, Philippines

BTW...on these new systems, a tech can come to your home and plug into the microprocessor and troubleshoot your complete system with a laptop or hand held scanner. This will tell him if there's any problems in the compressor components, the Freon charge pressures and any other trouble that's been logged. He can also reprogram your thermostat or even replace it if still under the warranty period. Since you rent this house, I'd first call the owner and say your having problems and would like this resolved before calling for service yourself just so the bill will go to the home owner.

There's also a filter in the system's air handler that might need changing or cleaning. Most new systems also now have a humistat that controls the house humidity and this might be why your system keeps running even when the temp has reached the set temp. It removes excess humidity and drains the water outside during a defrost cycle of the condenser coil.

And you can save about $10 a month if you set the thermostat to 72 degrees instead of the 70 that it's now set to.

farnsworth52 Loc: W. Pa.

I'm retired HVAC tech. Several things to check or concider with this. Most digital stats have a toggle or setting to run the fan constantly with A/C. It would be on the back of the stat. If the fan auto /on switch doesnt do it then check your program setting to see if the fan was left "on" in the indivedual cooling settings. When you check to see what temps are pre set also check to see if the fan has be selected to run constantly. Most newer systems will run the fan for a while after the temp is reached and the compressor shuts off. My guess is the cooling programs have been set with constant fan. Read your manual about setting cooling temps and times and fan selection will be there.If you turn the system switch from cool to off or heat and the fan shuts off within 8 minutes then the problem is in the stat and it's probably set wrong for your liking.

singleviking Loc: Lake Sebu Eco Park, Philippines

You must have been a terrible A/C tech if you didn't check the filter and condenser first to check for freeze up and proper air flow through it. Then the Freon pressures should be checked and the microprocessor codes downloaded to search through the trouble codes like the pressure reversal switch(used for condenser defrost) is defective. A good A/C tech would assume that the trouble is either the programming or improper settings but the fan control is not typically a portion of the program and is controlled by the fan control switch no matter if it's in program mode or manual mode.

farnsworth52 Loc: W. Pa.

I must have missed something. I thought his problem was the fan still running after the compressor cycled off on temperature. I concede the troubleshooting to you. Since you apparently have never seen a thermostat with a microswitch setting on the back for constant fan or a program option to run the fan in "on" even if the stat switch was turned to auto. My mistake sir,I leave the problem to you.

singleviking Loc: Lake Sebu Eco Park, Philippines

Swede's problem is that the compressor is still running even after the set temp is reached and as long as the compressor is running, the air circulating fan will continue to run no matter what the setting is in for auto or manual fan. His thermostat has a push button on the side for changing the circulating fan setting but the wiring could be in error in the way it's hooked up, as someone stated earlier in this thread. Swede has the installation and operating instructions for his thermostat and I assume they installed the proper model for his system.

We need to be careful though since this is a rental home so the landlord really has to be informed and go through him for service.

oleairman Loc: athens ga

I am not sure but if you have a new system and its one of the new high seer 14 or above it may have a variable speed motor on it to save you $$$$ ! have a new 16 seer its 100 plus degrees outside yep its going to be a running a lot..fan that is ..

quagmire Loc: Greenwood,South Carolina

probably the fan auto or on switch

Bobc163 Loc: Australia NSW

Been in the industry for over 40 years and I constantly get asked this and similiar questions
Answer
RTFM :mrgreen:
Seriously though the fan is designed to run constantly so that the system can measure the room temp air and cool it as required
in Heating mode the fan will cycle to super low when the desired temp is reached and then measure the air temp Super low is so that you do not feel a "cold" draught it is not available in cooling mode
If fan set to auto it will cycle through the fan speeds depending on the amount of cooling required
Good old Aussie no how :)

garceh Loc: florida

Here is your best answer.

Swede Loc: Trail, BC Canada

It's on Auto- runs constantly~
Swede

:| :|

jeep_daddy Loc: Prescott AZ

The fan running isn't good or bad. It should do whatever it's programmed to do; so if it's running but you've got it programmed not to run, it's not a good thing.

jeep_daddy Loc: Prescott AZ

Also, a lot depends on how hot the outside air temp is and how large your system is. Mine is a little undersized for the heat load in my house because my house has no shade in front where the afternoon sun is. The heat load from afternoon sun is tremendous and my AC unit can't keep up. So the best mine can do on a hot 90 plus degree day is cool my place to 78 degrees and it usually keeps running to maintain that.

Keeping your stat at 70 degrees is usually too cold for most homes unless you are playing table tennis and staying active inside your house. I'd be freezing at that set point. 76-78 degrees is usually good for most homes. My point here is that if you system is not very efficient and it's a very hot day, it may not be able to maintain 70 degrees so it keeps running.

singleviking Loc: Lake Sebu Eco Park, Philippines

After this comment, I'm a bit confused about what's constantly running. Is it the air circulating fan and the compressor or just the circulating fan that's constantly running?

Originally, you said that the compressor was always running. As long as the compressor is running, the air circulating fan will run as well, since it forces the air through the condenser. When the circulating fan is set to "AUTO" on single fan speed units, the circulating fan will run for a short period after the compressor turns off.

You then made a comment that after 30 minutes, the compressor was still running but the room set temp had been attained at a set temp of 70 degrees but when the set temp was increased to 72 degrees, the system shut off completely.
If this is what happens, it's the way things are supposed to work and the system is working properly. The circulating fan can be set to "ON" and the air circulating fan forces air through the condenser but the compressor stays off.

The compressor is the electricity hog in any A/C system and new high SEER systems are more efficient than previous generation systems but still are the major item consuming current. These high SEER systems, in many cases, have multi-speed or variable speed circulating fans in the air handler and some have 2 speed compressors for saving energy when only slight cooling of ambient air is required.

More energy savings can be attained through the use of thermostats that have programmed schedules for daily cooling that can increase room temps during periods where nobody is home and then turn on systems before you get home so your comfortable. This increased set temp during "Non-At-Home" periods or evenings and overnight periods when cooling is not needed, can significantly reduce utility bills.

So, to clarify what's really going on with your system?

1. Is the compressor always on when you set the temp manually (by pressing the "HOLD" button on your thermostat) to your desired 70 degrees even 30 minutes after the set temp is attained?

2. Does the compressor turn off when you change this set temp to 72 degrees and remaining in the "HOLD" setting?

3. Does your air circulating fan in the air handler turn off or is it a multi-speed or variable speed unit that constantly circulates air to monitor room air temp for it to determine if cooling is required? Remember...your thermostat has at least a 2 degree variable and will not turn on the compressor until the room temp is 2 degrees or more above the "SET TEMP" when the system is in the "HOLD" condition and bypassing the scheduled operating temps.

Once these questions are answered, I think an accurate determination of your problem can be determined. Many entries to this thread are assuming you are referring to the circulating fan motor of the air handler, but I gathered that your compressor is also not turning off even after the "SET" TEMP is achieved.

Please clarify.