Question about Heating & Cooling

1 Answer

Our AC unit @ the house is putting out heat instead of cold air. wastold it was the heat reversing valve was not opening and closing.

Posted by on

1 Answer

  • Level 1:

    An expert who has achieved level 1.

    Hot-Shot:

    An expert who has answered 20 questions.

    Corporal:

    An expert that hasĀ over 10 points.

    Mayor:

    An expert whose answer gotĀ voted for 2 times.

  • Contributor
  • 43 Answers

If you have a "Heat Pump" there are many causes for your reveresing valve not to close or open depending on which way your system works. You would be wise to have a qualiforned technician test your system to find the cause of problem.
Here is a list of things thast could cause the problem:
control wire for reversing valve disconnected or broken
wrong thermostat
thermostat gone bad
reversing valve coil defective
defrost timer bad (some makes)
system wired incorrectly
The above are just a few......

Posted on Jun 25, 2009

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

In AC mode the cooler fan doesn't turn on and after a little while the warm air starts to blow instead of cold air. Any ideas


Sounds like a bad or stuck reversing valve. Typically r.vs. are energized in cooling, verify 24 volts to valve, if yes , bad valve

Sep 30, 2016 | Whynter ARC-14SH ECO-FRIENDLY 14000 BTU...

Tip

Why your unit is freezing up.


To understand why your AC or heat pump is freezing up, it helps to know how your system works.

There are 7 major parts to an AC system, 9 with a heat pump.

1 - Condenser/heat pump (The outdoor unit)
2 - Air Handler (the indoor unit unless the system is a package unit, then all is outside in one system. The air handler is usually found under the home, in an attic, or in a closet.)

In the condenser are the following major parts.

3 - Compressor
4 - Condenser coil
5 - Condenser fan
6 - (HPs only) reversing valve

In the air handler are the following major parts.

7 - Blower motor
8 - Evaporator coil
9 - (HPs only) electric heat strips

Some systems known as "dual fuel systems" use another heat source in place of the heat strips, usually a gas furnace. I will address gas furnaces in another post.

When an air conditioner is operating properly several things are taking place.

1 - The compressor is compressing or "pumping" refrigerant through the system.

2 - through changes in pressure, the refrigerant makes the evaporator coil get very cold, and the condenser coil gets very hot.

3 - The blower motor/fan circulates air across the evaporator coils, as the room temperature air (Also known as "indoor ambient") goes through the cold coil, it exits, cooled approximately 15 to 20 degrees cooler than when it entered. (In a ducted system, the blower is also the fan that circulates the air throughout the home.)

4 - The condenser fan circulates air across the condenser coils. As the outdoor air goes through the condenser coil, it removes heat from the coils that are very hot. This in turn removes heat from the refrigerant so it can run its cycle again, and through pressure changes, cool the evap coil.

5 - With a heat pump, the reversing valve reverses the flow of refrigerant in the condenser and evaporator coils.
In AC mode, the evaporator coils get cold, and the condenser coils get hot. But in heat mode, the evaporator gets very hot, and the condenser very cold.

Now, whichever coil is getting cold will freeze up if there is inadequate air flow across the coil, as the refrigerant in it is far below freezing, and there is not enough airflow to keep the humidity in the air from freezing on the coil.

Things that can cause poor airflow are,

1 - Dirty/clogged coils
2 - dirty/clogged filter (will only effect evaporator coil)
3 - Closed/blocked vents (will only effect evaporator coil)
4 - Malfunctioning or dirty fan

Low refrigerant will also cause a coil to freeze up, reduce efficiency and cause the system to run for long periods of time. Not to mention, shortening the life of the unit.

With a heat pump, in heat mode only, the condenser (outdoor) coil will routinely begin to freeze up in cold temperatures. This is due to the fact that the refrigerant is below freezing, and the cold outdoor ambient temp is not warm enough to keep the condensation in the air from freezing on the coil.

Note, a properly working AC should never freeze up.

A heat pump is equipped with defrost controls to prevent ice buildup.
Some are controlled by timers, some by temp.

When a HP is going into defrost mode, the condenser fan shuts down, the reversing valve reverses the flow of refrigerant and the once cold condenser coil now gets very hot, defrosting the coil. (Many people have said this process sounds like the unit is coming apart, or about to explode and are frightened by the "smoke" which is really just steam from melting ice that comes off the unit.)

During defrost mode, the secondary or "auxiliary" heat comes on to ensure that you are still getting warm air from the vents. (Again, this can be electric heat strips or a dual fuel system)

If you are experiencing cold air from the vents during defrost, that means your auxiliary heat is malfunctioning.

The auxiliary heat is used for three purposes.

1 - during defrost mode to maintain warm airflow (automatic)
2 - when the HP cannot maintain the set temp due to extreme outdoor temps. It comes on when the indoor temp drops several degrees below the set temp on the thermostat (automatic)
3 - For emergency heat source when the HP is not working. (Manual)

To recap....

Iced up coils?

Poor airflow
low refrigerant
Malfunctioning fan
failing defrost system


There are two things that can be done in a pinch to help de-ice frozen coils. This may get you by until the repairman can get there, or you can fix the system if you are a do-it-yourselfer.

HPs frozen outdoor coil in heat mode, not going into defrost?

Cover most of the vents, and turn the system onto cooling mode until the outdoor coil is thawed. then uncover vents and return to heat, or emergency heat. (this usually takes 15 min or less)

Frozen coils in AC mode with a heat pump?
Turn the system to heat with the thermostat on just high enough to get the system to come on. (again, usually takes 15 min or less to thaw.)

AC only, with frozen evap coils? (this can sometimes be seen frozen all the way outside to the compressor on the copper lines.)

Turn the system off, and the fan switch from "auto" to on".
This will usually defrost the coils within 1 to 2 hours.
(If your system has the furnace in line before the evap coil, turn the system to heat, and the furnace will defrost the coil within minutes.)



on Dec 25, 2008 | Carrier XHB123D X/Y Series Heat/Cool Air...

1 Answer

My Honeywell thermostat isnt keeping my house cool even though the temp is set to 69. Currently 90 degrees in here


Its probably not the thermostat. The air conditioner may be stuck on heating mode. If its a reverse cycle, the reversing valve may be jammed so even when the thermostat is calling for cold air, it stays on heat. If the machine is on heating mode, it should be blowing cold air out of the outdoor unit of the air con. If its on cooling mode, the outdoor should be blowing hot air.

Apr 12, 2015 | Honeywell Heat/Cool Thermostat

1 Answer

Why can't I lower my honeywell 8500 below 67 on cool?


With a two story house you have to be aware that cold air flows downwards so any cold air coming from an ac unit will flow downstairs( normally down the stairway) so unless you can close off the down stairs then the up stairs unit will be cooling downstairs as well. Ac units have a thermostat located in the air intake and it cools until the cold air has risen to that point. In effect the space above the ac unit will be hotter than the floor. Knowing how they work ,you can see that the upstairs unit will never reach the set temperature because the cold air is continually heating from the house and will never get to the top thermostat.
So your solutions are
1-- fit controls that restrict the cold air from leaving the upper floor (Doors)
2--don't run the upper ac unit unless you are living up there (waste of money
)3 place an ac in each upper room and keep the room door closed

Aug 12, 2014 | Heating & Cooling

1 Answer

Using as heater and unit is blowing cold air


A heat pump is an air conditioner that reverses its refrigerant flow. In the cooling mode, the evaporator is cold to the room and its condenser is hot. In the heating mode, a valve reverses the refrigerant flow and makes the evaporator warm and the condenser cold.

Nov 24, 2013 | Soleus 10,000 Btu Portable Ac Air...

1 Answer

My 19 ft airstream's Penguin duo-therm a/c unit just started blowing out HOT air!!!! Why is this occurring?


If you have a heatpump model a/c unit, and it is blowing air that is hotter than the ambient temperature inside the airstream, then it is likely that your reversing valve is stuck in the open or closed position. A heatpump is basically an air conditioner that will also run in reverse (via the reversing valve) in order to heat instead of cool. The valve can get stuck for a variety of reasons, including; faulty wiring caused by rodents chewing or vibrations, insulators (dirt) between switch surfaces, or it could be a mechanical problem within the valve its self; these valves break often.

Sep 12, 2013 | Dometic Heating & Cooling

1 Answer

Heater and ac controlls not working 1994 corvette


Are all the vents working? Does your Cruise Control work (properly) it may work and shut off. If your vents are working is only hot air or cold air coming thru, or just your defroster vent?

You have a 3 way check valve under fuel rail guard on passengers side, its a pastic barrel shape thing it rots and creates holes in it causing your ac vents and cruise control to malfunction.

next your heater control unit if you have the one with a slider to regulate the hot or cold temperature breaks easily inside unit, its only plastic. Its an arm inside unit to control the temp in car it slides a door open or closed for heat. If you look where he slider enters thru that hole space you will see a post it sits on to open and close .

Nov 20, 2012 | 1994 Chevrolet Corvette

1 Answer

2004 mercury mountaineer.heat problem When turning ac knob to heat clicking sound like door opening and closing repeatedly sounds and air blows cold instead of hot.


2004 mercury mountaineer.heat problem
When turning ac knob to heat clicking sound like door opening and closing repeatedly sounds and air blows cold instead of hot.

Sep 13, 2010 | 2004 Mercury Mountaineer

1 Answer

I have a gas furnace that was to have a 10acc air conditioner unit installed with it. Instead of the 10acc unit a 10hpr48 heat pump unit was installed, The house is 4 years old and the reversing valve has...


it should definitly be warrantied. their is nothing wrong with your set up however id have the contrator pull a new wire and go dual fuel withh outdoor sensor and get the full benifit of dual fuel. you should use the hp above 40

Sep 16, 2009 | Heating & Cooling

1 Answer

Ac BLOWING HOT AIR INSTEAD OF COLD. All of a sudden my AC started blowing hot air instead of cold. It is set on cool.


Check to see if your outside unit is running. If not, check the breaker. If it is running you may have an issue with the reversing valve. It looks like three lines coming out of the top and one on the bottom. Trace the wires back to see that they are tight and secure. Of course, TURN OFF THE POWER first. good luck.

Apr 18, 2009 | Hunter 30124 Air Conditioner

Not finding what you are looking for?
Heating & Cooling Logo

Related Topics:

68 people viewed this question

Ask a Question

Usually answered in minutes!

Top Heating & Cooling Experts

paulcarew

Level 3 Expert

2461 Answers

Dan Webster
Dan Webster

Level 3 Expert

8220 Answers

Donni Steen

Level 3 Expert

659 Answers

Are you a Heating and Cooling Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...