Question about Fujitsu Heating & Cooling

2 Answers

Outside unit freezing when ambient temp drops to 0 & below which causes the reverse cycle heating unit to stop working

Posted by on

  • robandfloyd Jul 16, 2010

    daikin reverse cycle air conditioner freezing on outside condensor and shutting down unit
    this occours when ambient temp reaches 0 and below

×

2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 4,059 Answers

When there is enough moisture in the air and the heater is running the moisture will freeze on the outside coils. When the unit senses this it reverses to the cooling mode which sends warm freon to the outside to melt the ice and then it will switch back to the heat mode. If this is the way yours is operating it is normal. It will help to shield it from rain and snow.

Posted on Jul 16, 2010

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Guru:

    An expert who has written 7 tips or uploaded 3 video tips

  • Master
  • 468 Answers

Actually, as the ambient increases the outside unit becomes more inefficient. Remember, air conditioners are merely heat pumps, they pump heat from inside to the outside adding in their own heat generation while they do so. The hotter the outside temps are the less efficiently can the fans cool the condensor coil. If the condensor isn't as cool as it can be, the indoor unit will be able to evaporate to a smaller extent, effectively dropping your cooling capacity. Reverse cycle is by far the most energy efficient system. If you calculate electricity input to heat production, you get 300% apparent efficiency. The reason is that they are heat pumps - they move heat from one place to another, rather than generate heat by burning fuel. But as the outside temps fall the unit can start to ice over which them forces the unit to shut down. If you live in an area where the outside temps drop below freezing or get down to 3-5� then a reverse cycle might not be the best. www.fujitsugeneral.com/PDF_06/halcyon06_brochure.pdf

Posted on Jul 16, 2010

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

Rear window washers work in all temperatures. Front washers work only when outside temps are above 0 ! Once temps are below zero there is nothing!!!


Sounds like you got it. Water is freezing up the wiper motor or wiper transmission at a certain temp due to water leakage in what is supposed to be a sealed area. (inside wiper motor, wiper trans linkage). "SOUNDS LIKE" water may have seeped in the moer seal & froze it or stripped the gears of the wipers? Good Luck Frank M

Feb 15, 2016 | 2014 Hyundai Santa Fe

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...

2 Answers

Heater will not activate until outside temp. is above 40 degrees


If you have a heat pump the compressor is locked out below that temp. If you have a dual fuel - hp/gas, the gas burners should come on as would the electric heaters if you have electric heat as backup.

Jan 19, 2016 | Heating & Cooling

1 Answer

I have a Rheem Heat Pump unit. This winter, the outside unit fan at times trips off, but the inside unit keeps running continuously. I woke up one morning & it was 62 in the house. The inside unit ran...


Dear Friend!

Due to very low ambient temp, the fan will not run. Once the pressure build up, it's automatically run for some time and again cut off. But if you keep Heat mode and still tem not raised in your room means the reversable valve not working and hence the compressor and out side fan also will not work. Keep "Heat" mode and temp setting +29 to get better heat. Hope is it helpful?

Dec 10, 2010 | Heating & Cooling

1 Answer

I have a heat pump and it freeze up


If you are referring to the outside unit freezing up, the issue is in the defrost cycle. The defrost cycle works something like this: The unit reverses the flow of freon causing the inside coil to blow cold air into the conditioned space and the outside coil is now working like an a/c unit, it gets warm to melt the frost/ice. The inside unit electric heat strips come on so you do not notice the cold air being blown in. The fan on the outside unit stops running to allow the coil to get good and warm.
Now the unit should go into the defrost cycle every 90 minutes or so. It should not terminate the cycle untill the coil is clear of frost. There is an "Klixon" type termostat that measures the temperature of the outside coil. This is most likely the problem. It is prematurely terminating the defrost cycle. I'd start there first.

Hope this helps, Let me know if I can be of any further help.

Dec 29, 2009 | Intertherm P3RC-030K Air Conditioner

1 Answer

HEAT PUMP OPERATION FOR TEMPSTAR SMART COMFORT 2400, MODEL THC436AKC1. LOWEST OUTSIDE TEMPERATURE FOR OPERATION?


I have installed many heat pumps and if it is installed without and ouside temperature sensor I would not recommend running it below freezing 32 degrees farenheheit. Running a heat pump at low outside ambient temps. can hurt your compressor and that is the most expensive part of the outside unit.

Dec 20, 2009 | Heating & Cooling

1 Answer

Should the LG LS-K-1830CL outdoor unit ice over on the coils when operating in the heat pump mode? Would this cause the unit to not properly heat the room?


Running the heat pump in low outside ambient temps. will definitely cause the coil to ice up. An ouside temperature senor or a wind baffle should be installed in climates that get below freezing. This would definitely cause the heat pump to operate at lowered efficency and maybe not at all. It should go into defrost mode if the sensor is working correctly when the coil ices up.

Dec 20, 2009 | LG LS-K1830CL Cool Mini Split Air...

2 Answers

FREEZER NOT FREEZING CONTENTS


I have a similar problem with danby and have been unable to get help - I now HATE Danby Chest Freezers

Mar 10, 2009 | Danby 5.5 cu. ft. / 156 liter Chest...

1 Answer

Condenser frost's up on my heat pump


On a heat pump the system reverses during the heat cycle to bring in outside heat that will cause the outside coils to ice up. There is a defrost timer or pc board to send the unit into defrost every so often. This is a common problem with heat pumps or possibly low or refrigerant. Heat pumps will freeze up at low outside temps, but unless your in the Artic right now that shouldn't be a problem.

Sep 27, 2008 | Heating & Cooling

3 Answers

Short cycling


The most common cause is the fan relay on the main circuit board. However, if the outside temperature is 30degF and the inside is 60-65degF then the cause could be the insulation is ruined or missing on the backside of the unit's firewall. This can cause the unit's internal thermocouple wire to read below 45degF which is the freeze sentinal temp level. Anything below this temp level will cause the unit to come on for a few minutes to warm up the air and bring it to 46degF or higher to protect internal plumbing from freezing.
The best way to check for this is to manually set the unit to one of the heat modes and the thermostat up just until the heater comes on. Let it run until the unit turns itself off. Then set the mode switch back to Off and see if the unit still cycles on and off as before.
If it does then the main circuit board should be replaced unless you are comfortable de-soldering and re-soldering another fan relay in place.

Dec 20, 2007 | GE Zoneline AZ38H12DAD Split System Air...

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

Related Topics:

77 people viewed this question

Ask a Question

Usually answered in minutes!

Top Fujitsu Heating & Cooling Experts

Fotis Papastamatiou

Level 2 Expert

96 Answers

AJMAL KHAN

Level 2 Expert

382 Answers

Donni Steen

Level 3 Expert

659 Answers

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

Answer questions

Manuals & User Guides

Loading...