Question about Honeywell Programmable Thermostat Heater

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I just moved into this home and am wondering what EM heat is compared to just Heat and my outside unit is full of frost what do I need to do?

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You have a heat pump and EM means it takes the heat pump out and uses the back up heat weather it be gas or electric. With your unit frosted up outside you might want to put it back on regular heat and watch the unit outside to see if it comes on first of all and then should go through a defrost stage. Makes a weird sound don't think nothing about it that is normal. Your outside temp. right now really cold to frost up the condensing unit. Let me know if you need anymore clarification or help ok. ken

Posted on Feb 01, 2010

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Hi, EM stands for emergency heat. You should only need to use it if the outdoor unit does not operate. You have what we call a heat-pump. If the outdoor coil is iced up, it should go into a defrost cycle to melt away the ice. You will know when it does as you will see steam coming up from the unit as though it is on fire. The outdoor fan will also shut down during this process. These units will defrost using time and temperature to defrost the coil. If the ice continues to build-up, and does not defrost every couple of hours, I would say you have a faulty defrost board or defrost thermostat. There is not alot you can do as these are very complicated systems to work on. You will more then likely have to call out a service tech to check this outdoor unit for you.It also should have heat strips in the outdoor unit for EM heat if the outdoor unit fails. If it is iced up it is on and running. Thats what I would do is keep an eye on it to see if it does defrost, and if not, you will need to get a tech out to check it. It takes special equipment to check these units. Please keep me posted.
Sincerely,
Shastalaker7

Posted on Feb 01, 2010

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1 Answer

When em heat is on my outside unit runs but when not on em heat it doesn't. Which setting is best to use?


Has this always been this way? When the emergency heat is on the outside unit shouldn't run. When in normal heat, no emergency heat, the outside unit should be running unless the temperature is below the balance point ( usually around 35 degrees). If this has always been this way and the outside temperature is above 40 degrees you might have your 1st stage and 2nd stage wires switched.

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Hi,
There is ice built up on the fan blades and they are out of balance so they do not move any air....you will need to melt the ice off of the fan for it to work...
The "EM Heat" is to bring on the electric backup heat coils if you have them... you could use that temp. but it will cost you more $$

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I have a Lennex heat pump unit which was installed in 2008. Our area (Savannah, GA) has experienced some abnormal cold temps lately. Yesterday, I noticed the outside of the unit had frost on the unit. ...


Heat pumps are the same as an A/C unit only it works in reverse. Instead of blowing cold air inside and hot air outside it blows hot air inside and cold air outside. The heat being blown inside is extracted form the cold air outside. Its called Latent heat Latin for hidden. Believe it or not even though its 20 degrees outside there is still heat in the air. Example if you want to drop the temperature of a freezer from 20 to 10 degrees you have to remove heat .I know your getting unusal weather and that is the problem. Heat pumps can only work no lower then around 20 degrees outside.Heat pumps are never used above the freeze line. With your unusal temperatures thats basically where you are now. Ride it out. When your temps rise a little your be fine. Im in Chicago.

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I HAVE SAMSUNG AQV12F2 VE ROOM CONDISIONER ,NOW OUTSIDE IS -3C,HE IS HETING OLL THE TIME IN FULL POWER BUT HE CAN NOT MAKE 23 C AT HOME, PRIVIOSLY HE WAS HEATING WITH NO PROBLEM EVEN AUTCIDE WAS -15C.?


To getproper heat, keep your temp setting at 25+ degree and also mode in "heat"position. If still no heat, check your heating sensor for closed circuit by anOHMs metre.It it's with RV, check power to RV And also check your compressor is not frosting due to -3 degree.

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I have arcoaire thermostat (not digital) with Comfort Air FBA series system, vintage 1998. The bottom of thermostat has selections: ''EM Heat'' ''Heat'' ''Air'' ''Off''. I am not original owner. Q. Should...


yes go into electric heat for awhile. sometimes a heatpump will run constantlly when temps outside are not high enough./em heat mode untill temps rise or unit recovers.your unit should of gone into hot-gas defrost this maybe what your hearing. but remember electric heat is expensive to operate go back to your heatpump mode after system has a chance to recover.

Jan 31, 2010 | Heating & Cooling

1 Answer

Heat pump runs in em heat when outside temperature is low


Yes, you may turn to em heat only. May this confirmation help you.

Jan 06, 2010 | Heating & Cooling

1 Answer

New heat pump system freezing, questioning wiring.


W1 and E on stat need tied together. When W1 comes on wire where all heat elements come on. On the outside unit defrost board set the 45-60-90 to 45 and see if that takes care of the frost problem.

Jan 03, 2010 | Heating & Cooling

5 Answers

What's the difference between EM HEAT and AUX HEAT?


Sorry, neither of these answers are completely correct.
You have a heat pump (or the wrong thermostat). Let's assume you have a heat pump.

In air conditioning mode, it works like every air conditioner you have ever had, but...

In heat mode, it reverses its operation. Have you ever felt the air coming out of the outdoor unit of your A/C unit? It's hot, isn't it. And the air coming out of the indoor unit (out of the registers) is cold. Now for a heat pump to produce heat it simply runs the air conditioner in reverse and the heat comes out in the house and the cold is released outside. Neat, huh!

Here's the problem with heat pumps...when it is really cold outside the heat pump can't produce enough heat to heat your home. So it has an additional heat source called "Auxiliary Heat". This heat comes on automatically when the house doesn't get warm enough. The source of this heat is based on the region of the country you are in. North/Northeast generally have oil heat, other regions have gas, and still others have to use electricity to heat. In Texas, we usually use electricity as the supplementary heat on heat pumps. VERY EXPENSIVE!

Now the "Emergency Heat"...this is exactly as stated in Solution #2. This is manually turned on by YOU at the thermostat when your heat pump fails. This turns on the auxilliary heaters and turns off the heat pump (remember, the reverse air conditioner). Again, this can be quite expensive to run if your heat source uses electricity! Gas and oil may be cheaper. The emergency heat is only designed (normally) to keep the house livable (not comfortable) until the Heating Tech can get out to you and fix your heat pump.

Something else you should know. It is normal for a heat pump's outdoor coil to frost up during heating mode. It will detect this and go into DEFROST mode and melt the frost off the coil. While it is doing this, it will turn on the auxilliary heater to keep the air blowing in the house at a reasonable "warm" temperature, but it will not be as hot as normal. In fact, heat pumps produce a lower temperature heat than traditional heaters. So the air may feel cooler during heating than you are use to anyway. This is normal and is not a sign of a problem.

So what do you do: Set your thermostat to the temperature you want and set the controls for HEAT/COOL and FAN-AUTO/ON and leave the EMERG HEAT off unless your heat pump breaks.

As always, keep your filters clean and your outdoor unit's coils clean and free of debris.

Hope this explains your question for you!

Oct 16, 2009 | Ruud Central System Air Conditioner

1 Answer

UNIT NOT BLOWING WARM AIR-OR REACHING DESIRED TEMP


I assume this is a heat pump. The outside unit may be icing up. It should have a defrost cycle with electronic control that sometimes fails or sensor associated with the electronic determination of when to defrost may have failed or may not be sensing because its out of position. You can check for a defrost problem. If frost is blocking the outside unit air will not pass through it after the frost builds up and you may be able to see the white frost as well. If all this is true you need to get a service manual and use its procedures to find out why the unit is not defrosting.

Jan 12, 2009 | Weather King 12AJA4801AH Air Conditioner

1 Answer

Compressor fan not running


Does it look like the coils are frosting over? Is it steaming? Keep watching, after about 30 min does the fan come back on?

If yes to any/all the above then the unit is probably in defrost mode and yes the fan will stop blowing during that time, but restart when the unit goes back into regular heat mode.

During this time you will likely notice warmer heat from the vents than normal and the "AUX or EM HEAT" light will be on.

That is your backup heat system. It should automatically come on during a defrost cycle.

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