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DuoTherm Model 59516.331 needs heat strip added

I don't know if this is conventional a/c or heat pump, but we need to add a heat strip. Can that be done? If so, what is required, controls, relay, thermostat?

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  • dmorton Dec 12, 2008

    Just what I needed to hear. Thanks for the help.

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MODEL SERIES: 579XX, 590XX & 59516 (60XXXX, 61XXXX ON PAGE 2) ALL MODELS ARE PREWIRED WITH A POWER RECEPTACLE IN THE ELECTRIC BOX FOR EAS Y INSTALLATION
USE PN 3101121.030 HEAT STRIP,FOR NON-DUCTED MODELS

Posted on Dec 12, 2008

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If the air conditioner goes out can i still use the heater


If it is a conventional heat pump the answer is no. If you also have an electric heating strip for "emergency" you can use that for heat but the expense will send you to the poor house.

Jan 01, 2016 | Air Conditioners

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Electric heat strips are not for heat pumps only this is a form of heating in...


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 Jan 04, 2009 | Carrier XHB123D X/Y Series Heat/Cool Air...

1 Answer

Wiring from coleman rv ac unit has 6 wires and duotherm rv ac unit has 10--what do you do with other wires


you need a wiring diagram of each to see what they are for. heat pump, auxillary heat, inside sensor, outside sensor, electric heat, gas heat there are many different applications.

Aug 20, 2015 | Coleman Air Conditioners

1 Answer

How to tell if your unit is a heat pump or just air conditioner with electric heat strip


PTH is a heat pump. PTC is an air conditioner only. I don't believe Amana makes electric heat strip-only models based on what I see in their literature. You can just do a google search and look for yourself.

Nov 29, 2011 | Amana PTH123B25AJ Heat Pump Air...

1 Answer

''EMI'' heat w/ac acts weird.


Hi, what you have here is a ductless heat-pump split system. In the heat mode the compressor will run on a heat pump as it uses a reversing valve to reverse the flow of freon to heat your house. If it gets cold enough, the stat will call for the emergency heat strips to energize to come on for back up. Now, if the unit does not come on or go off when the thermostat calls for either heat or cool to come on and it just does it whenever it wants to, the stat will have to be replaced with a new one. If you plan on doing this your self, I would get the exact same heat-pump stat as you have because they make so many different models that the wiring may be much different and you will be lost when you go to wire it up. The heat - pump has many more control wires on them then the conventional heat/ac unit. So make it easy on your self and get the same one. They are easy to replace. If it is ignoring the settings its the stat. Heat strips and compressor running in the heat position together are normal for a heat- pump.
Sincerely,
Shastalaker7

Mar 17, 2010 | Air Conditioners

1 Answer

Can I install emergency heat strips by myself? Our heat pump does not have them, so it's 56 degrees in my house right now. Help!


Sounds like your heat pump may be undersized or is not defrosting frequently enough. But in answer to your question, they are not that difficult but if it was installed without strips, your power supply may not be enough. You will also have trouble purchasing them unless you can buy from a HVAC supplier. I would look into the heat pump function and the power supply. You may need to make some modifications before adding strips.

Jan 02, 2010 | Weather King 10AJA2501AH Air Conditioner

2 Answers

I would like to know the specifications of my Goodman model CPKE42-18 AC/Heat pump system. BTUs heating and cooling? Thank You,


Many HVAC people talk in tonnage. One ton is equal to 12,000 Btus. Therefore your model specifies your cooling tonnage at 3 and 1\2 tons. Your heating would be determined by how many if any supllimentary heat strips are added. If you live in Anahiem or Miami that's not really important. But if you live anywhere that gets down into the 40's at night you'll want strips. Cooling wise depending on where you live and what your insulation is like, I'd say your unit is good for 1100-1300 Sq feet of living space.

Jul 15, 2009 | Goodman Air Conditioners

1 Answer

Does not heat real hot or cool real cold . dometic duotherm penguin markings on 85 or so unit


Heat real hot? Is this a heat pump or do you have a heat strip installed. Get a regular thermometer and put it in the outgoing vents of the unit. Register the temperature there and then the outside temp. If it is cooling at 17 to 23 degrees below ambient temperature, the manufacturer says this is fine. Try cleaning the condenser out on the top of the rv. Gently hose the rear condenser out until all the dirt and grime is removed the unit. Try cooling again and see if it is better.

Jul 04, 2009 | Dometic Rooftop RV Air Conditioner

4 Answers

Goodman Air Conditioner not heating well...


Heat pumps in cold climates suffer a number of limitations stemming from the fact that they are designed for air-conditioning applications. As climates become cooler and heating becomes more of the primary HVAC function, one may find that conventional heat pumps lose capacity and do not satisfy the load of the conditioned space. In colder temperatures, a conventional system’s need to defrost can further detract from heating performance. The use of resistance heat or fossil fuels to supplement or replace the vapor cycle. The additional use of supplemental heat to temper cold air blowing into the space during defrosts. As it gets colder outside, the delivery air temperatures inside begin to fall when no supplemental heat is being used. Supply air temperatures that are warmer than the return temperatures add heat to a space, but discomfort occurs when these supply temperatures drop below skin temperature. The air movement can feel cool or even cold. While the heat pump may be operating exactly as intended,the consumer will desire a more comfortable environment.

Jan 18, 2009 | Goodman CKL49AR49 Air Conditioner

1 Answer

HEAT PUMP WILL NOT KEEP UP WITH THERMOSTAT SETTING


Heat pumps in cold climates suffer a number of limitations stemming from the fact that they are designed for air-conditioning applications. As climates become cooler and heating becomes more of the primary HVAC function, one may find that conventional heat pumps lose capacity and do not satisfy the load of the conditioned space. In colder temperatures, a conventional system’s need to defrost can further detract from heating performance. The use of resistance heat or fossil fuels to supplement or replace the vapor cycle. The additional use of supplemental heat to temper cold air blowing into the space during defrosts. As it gets colder outside, the delivery air temperatures inside begin to fall when no supplemental heat is being used. Supply air temperatures that are warmer than the return temperatures add heat to a space, but discomfort occurs when these supply temperatures drop below skin temperature. The air movement can feel cool or even cold. While the heat pump may be operating exactly as intended,the consumer will desire a more comfortable environment.

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Jan 17, 2009 | Air Conditioners

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