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THANK YOU HI I DO HAVE A HEAT PUMP WHO RUN THE DEFROST MODE TIME TO TIME ON AC MODE AND IS VERY HOT OUT SIDE AND WHAT IS FUNNY I TS WORK VERY GOOD ON WINTER PLEASE SOME BODY HELP GOD BLESS.

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  • SIDI94 May 26, 2009

    HI AND THANK YOU MY AC WORKS BUT SOME TIME THE HEAT PUMP GO TO THE THE FROST MODE AND THE FAN STOP AND YOU GOT THAT SOUND OF THE HEAT PUMP AND NO MORE COLD AIR ONLY WARM SO I TURN OFF THE UNIT

  • Paul McGrath
    Paul McGrath May 11, 2010

    DON'T UNDERSTAND YOUR PROBLEM

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  • Master
  • 3,433 Answers

Are you saying your air conditioner does not work? If so, make sure the ac is mode is select and not on heat. Then turn your thermostate down to around 74 degrees . The heat/cool select is on your thermostat. Good luck and keep in touch.

Posted on May 26, 2009

  • Ned C Cook
    Ned C Cook May 26, 2009

    oK, it's going into defrost mode because the evaporator coils are icing upresulting in blockackage of the air flow. Don't set your thermostat so low the machine runs constantly. In high humidity it will ice up real quick . Set it at a comfortabltable 72, and that allows the nachine to cycle on and off giving the ice a chance to melt and open up thee air flow again.. Let me know the outcome. please.

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Why contactor on heat pump will not energize heat mode?


Heat pump and AC are basically working the same principle. When you turn on the heat pump is just like to turn on the AC. The main contactor will energize to turn on the compressor. The only difference is the 3 way valve, either switching to AC mode or heat mode. It is the most commom problem for heat pump. Check the thermostat wires for heat mode and defrost control.

Feb 05, 2015 | Heating & Cooling

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

Heat Pump Blowing Cold


Unless you just installed or had the thermostat installed recently, I would not point at the thermostat as the problem. With what you have described I would suggest have your units serviced as it sounds like a loss of charge, or failed defrost control board. The "Aux" comes on when the unit is using secondary heating (electric heat strips). That occurs when the demand temperature (what you set it to) in Heat mode is more than the current room temperature, usually ~2-4 degrees higher. Also happens in defrost mode. Defrost is a heat pump cycle that melts any build up of ice on the condenser unit (outside unit). That process is simply the unit running in cool mode which will heat up the outside unit to melt any ice. Defrost cycles vary with manufacture but usually you can tell if is in defrost by looking at the outside unit, during defrost the unit will be warm or hot sometimes there is steam and the compressor will be running but not the fan. Defrost only happens on heat pumps in "Heat" mode. Rheem has a 10 yr compressor and parts warranty, so call the installer or Rheem authorized service company.

Nov 11, 2013 | Honeywell RTH7600D Touchscreen 7-Day...

1 Answer

No heat from vents


As per your problem mentioned. There are few solved help links to troubleshoot these problems. Go through the list and Click the link below:----

2000 Toyota Avalon: No heat on Passenger Side?

http://whatisbyme.blogspot.in/2012/05/2000-toyota-avalon-no-heat-on-passenger.html

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No heat on Oldsmobile Silhouette?


http://technoanswers.blogspot.in/2012/02/no-heat-on-oldsmobile-silhouette.html

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Heater blows cold?

http://schematicsdiagram.blogspot.in/2012/02/heater-blows-cold.html

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Heat blows cold on drivers side and hot on passenger side?

http://schematicsdiagram.blogspot.com/2011/12/heat-blows-cold-on-drivers-side-and-hot.html

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Hot air on the driver's side vents only?

http://repairhelpcenter.blogspot.com/2012/01/hot-air-on-drivers-side-vents-only.html

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Temperature gauge does not move and no heat when heater is ON?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-does-not-move-and-no.html

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1992 Toyota Camry: A/C Control light Flashing and A/C not Blowing Cold?

http://technoanswers.blogspot.in/2012/04/1992-toyota-camry-ac-control-light.html

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No heat, blower blows only cold?

http://technoanswers.blogspot.in/2012/02/no-heatblower-blows-only-cold.html
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Ford F150 Ac only blows through defrost vents?

http://technoanswers.blogspot.com/2012/01/forf-f150-ac-only-blows-through-defrost.html

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Dodge A/C come out of defrost vents only?

http://technoanswers.blogspot.com/2012/01/dodge-ac-come-out-of-defrost-vents-only.html

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Ac vacuum line on dodge cummins?

http://technoanswers.blogspot.com/2012/01/ac-vacuum-line-on-dodge-cummins.html

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Ford ranger AC blows cold through defrost vents instead on cabin vents?

http://technoanswers.blogspot.com/2012/01/ford-ranger-ac-blows-cold-through.html

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2005 Chrysler PT Cruiser: A/C Blows Warm?

http://whoisbyme.blogspot.in/2012/06/2005-chrysler-p8t-cruiser-ac-blows-warm.html


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2009 Mercury Grand Marquis: A/C blows Cold From Defrost Vent Only?

http://whoisbyme.blogspot.in/2012/06/2009-mercury-grand-marquis-ac-blows.html

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AC not blowing through Vents on 2007 Chevy Trailblazer?

http://schematicsdiagram.blogspot.in/2012/04/ac-not-blowing-through-vents-on-2007.html

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Passenger side temperature is warm air out of dash vents?

http://schematicsdiagram.blogspot.in/2012/04/passenger-side-temperature-is-warm-air.html

----------


These will help.

Thanks.

Nov 28, 2012 | 2006 Ford Taurus

1 Answer

Hard-wiring for a 4 ton heat pump


I cant really explain in detail every wire goes to X, However
All units regardless of design will have common requirements electrically .
As you know the power is 2 hot legs of 115v and a ground for the high voltage side, and 24 volts for the control circuits.The 230v will enter on the contactor,some use 1 leg, some both, some use the start winding as a crancase heater and will not be opened by the contactor.
That said the L1 and L2 legs will go to Common and Run terminals on the compressor, the run cap will be run and start, a start cap with a potential relay will be 5 to common, 2 to start and 1 to 1 side of the start cap the other side of the start cap is Run so the leg that goes to run will be run to run to run, run winding to run cap to r on start cap.
most use PTC THERMISTOR START ASSISTS SO THE OLDER RELAY i DESCRIBED MAY NOT BE THER HAVING A START ASSIST THAT SIMPLY WIRES IN PARALELL TO THE RUN CAPS TERMINALS R AND S or run and start.
The defrost is exactly how a domestic ****** works, time AND temp
initiated, time OR temp terminated, using a mechanical timer as Ranco E15 or a solid state board if newer, 1 leg of the condenser fan will be ran through the defrost timer as wll since defrost is just AC mode with the condesnser fan off, and the strips will temper the air so not to cool the home as the units defrosting . the sequence of operation and types of relays will matter, but at this type of communications I cant get much more detailed, without specifics, the low voltage is as any AC except with a Orange for reversing valve thast is energized in heat or cool mode, try O and if opposite put the wire on B on the stats subase.

Feb 24, 2012 | Heating & Cooling

2 Answers

I have a Mitsubishi heat pump that runs well but the outdoor unit does not defrost what could be the problem.


Why does my heat pump ice up in Winter?
Heat pumps naturally ice-up in the winter. It is normal for the entire coil to be covered in a white frost and even light ice, during cold weather conditions. However, it is bad for the entire unit to be encased in ice. This indicates ductless heat pump problems which should be addressed quickly to save energy and avoid serious damage to your ductless unit. These systems should periodically go into a defrost cycle. This keeps the unit running efficiently. If the coils are blocked by ice, proper heat transfer between the coil and the outside air will not occur.
How does the defrost mode work?
When the mini split heat pump goes into defrost, the reversing valve inside of the outdoor unit is energized, switching the system from heat to the air conditioning mode. The outdoor coil becomes the hot, the indoor coil becomes cold, and both - the outdoor and indoor fans shut off. This allows the outdoor coil to melt accumulated ice. When the built-in micro-computer analyzes that all ice have been melted, the heat pump heating system goes back to heating mode.
sanyo-mini-split-defrost.pngA cloud of water vapor may be seen rising over the outdoor unit and a "whoosh" sound can be heard as the refrigerant reverses direction. The entire process usually takes up to 10 minutes (depending on conditions).
How often does the system goes into defrost mode?
Ductless mini-split heat pumps have different ways of determining when to go into defrost. The built-in microcomputer determines outdoor temperature, refrigerant pressures, and several other factors. In colder temperatures the system will go into defrost more often than in warmer.
If a ductless mini split heat pump is severely iced-up in the winter it is possible that it isn't defrosting (though there could be many other causes). Let the manufacturer certified technician check your system

Oct 29, 2011 | Mitsubishi Mr. Slim MXZ30TN Air...

1 Answer

I have a 1994 buick lesabre. the car does not blow air or heat from the vents.. it only blows from the defrost vent. i also have the issue that the car only blows hot air when the ac is running.. i tried...


The air circulation system is designed to go into default mode if it cannot function properly. Default mode is defrost only. That could also be why your getting heat only. The main reason that the system goes into default mode is a vacuum leak. Check the vacuum servo motors that operate the vent doors with a hand held vacuum pump. They are usually located under the dash. If this is the problem then the freon level will have to be corrected or else the AC operation could be effected.

May 13, 2011 | 1994 Buick LeSabre

1 Answer

My amana heat pump will start and run momentarily and stop several times, and eventually it works, the house stays at 70 degrees so it works but this does not sound right what's the problem if any?


Hi; I need more info. Do You mean the outdoor unit is stoping and starting while running in a call for heat by the tstat. When heat pumps run if the temperature out side reaches low enough the outside unit will go into a defrost cycle to remove any build up of frost or ice. If the outdoor unit has a dirty coil or a low freon issue this also can trick the unit into a premature defrost cycle. Now here is another scenerio.If Your ac is running in the cool mode and stops prematurly there could be several problems. Low freon level, faulty fan motor causing the compressor to go into a freon bypass mode wich sounds very spewy. Please tell me if you are in heat mode.. Also how old is the unit. Sometimes a severly worn control contactor can disallow all the needed voltage to cross over to Your fan motor and compressor. Watch unit while its acting up... Also when unit goes into a sceduled defrost the fan will stop this is normal and will restart when the unit comes out off defrost You will here this big swoosh sound. Thats the freon being redirected back into the heating path.Let me know...alpharome416

Jan 22, 2010 | Heating & Cooling

1 Answer

Heat pump only runs for a few min in heat mode, then switches to cool and will not produce warm air until the system is turned off and back on.


Hi,
The defrost sensor or timer is bad. When the heat pump runs in heating mode the outdoor coil gets very cold and needs to defrost every four hours or so. When it does this it goes into cooling and turns on the auxiarlly heat.
The unit will have to be checked to see if the timer is just going right into defrost mode or if the sensor is telling it to go into defrost mode.
It probably would not be a bad idea to just replace the both pieces since they work in conjunction with each other.

I hope that this will help you to solve your problem!

Thanks for using Fixya!!

Heatman101

Dec 25, 2009 | Heating & Cooling

1 Answer

My heat pump starts up in the defrost cycle.


My question may seem a little ignorant but How do you know your heat pump starts in defrost? You can't tell by "feel". You have to measure heat with a thermometer. If its because it "feels cold" your body temp is normally 98.6'f if your heat pump is in cold air outside (say below 40 or 45'f) and its putting out 85 to 98'f air inside your home is gaining even if it feels cold to you. Hearing the reversing valve kick in or out? Just because you hear this doesn't mean its in defrost, it may normally start this way.

Now if its running for a long time? That's subject to your interpretation of long time. It could be normal too especially if the air outside is getting colder and your house is needing more heat to keep it comfortable for you. The longer the heat pump runs means the more electric it is saving you.

The one thing that makes me believe this is all normal is the fact you say the elements kick on and warm up the home before it shuts off. So heres one way to kind of tell where your at:
1 Are the filters cean?
2 When the weather warms up does the Heat pump run as long?
3 Does *** run longer as the night gets colder?
4 Does it defrost at times and you see steam coming off the out door part and the out door fan stop?
5 does it make a swishing noise just before it defrosts and maybe after it defrost?
6 does it make ice build up around the base if its been running for a few days?
7 does the air comming out the ducts test at least 5 to 8'f warmer or more, than the room temperature?

If all of these are yes then most likely you have a normal operation going on.

If the elements are coming on that usually means the heat pump cant handle the load by itself. Remember this :
It uses less electricity to run the fan motors and the compressor < 18 amps in cold weather. Typically with everything clean heating output on a 5 ton somewhere around 50,000BTUH [a 3 ton will put out around 28,000 btuh and only pull about 12 amps] you would have the indoor fan motor running any way with either of the heating systems so it isnt needed to count for effiency.
1 heating element 5KW at 240V about 20.83 Amps and it puts out only around 17,000 Btuh. But the heating element glowes red hot and consentrates heat in a shorter time thus it "feels" warmer, which it is but its not cheaper.

If this help\ed you understand your heat pump operation and you feel like it is normal now please rate me as high as you can. If you feel you you may still ahve a problem please post it and the answers to the questions above as to narrow your scope of what to look for. Thanks for using fixya and good luck.

Nov 18, 2008 | GE GSS25JFPCC / GSS25JFPWW Side by Side...

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