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My lennox heating system will not kick on when the temp drops and I have to manually set it every time....what to do?? Im freezing

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  • polarcub Dec 28, 2008

    Thanks skeeter140 for that info. However, I found out that I hadn't programmed correctly to set for the right temp throughout the day and night. Thank goodness that was the problem.

  • belltoo Jan 26, 2009

    we have battled the Lenox furnace for years. Several pro's have came out and tightened cleaned and one even changed the thermostat. It work ok for a week may be two and then it want come on. At first fault switching it on and off or running the thermostat setting below and above the extremes made it come on, after a while you get nothing. A few years ago I the same problem and I changed out the spark plug wire and it fixed it. Last year I have the pro come out and he was suppose to have done that same thing and hopefully avoid the hassle during the winter, don't remember last winter but this winter the same old junk. I guess Lenox pulse high efficient units do save me money??? But it a cold cost.

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Sounds like your t-stat is failing you. Here is a test you can do. Take the front cover off. Locate the R terminal and the W terminal. Get your self a short piece of wire small diameter say 18 gauge. Now take your wire and jump across the two terminals hold them there and if you hear your furnace kick on then the t-stat is bad. let me know what you find out. ken

Posted on Dec 28, 2008

  • Ken Bledsoe Dec 28, 2008

    Well at least it was the t-stat can you pull your rating as it down grades my overall ratings. You don't have to put any rating on me as you found the problem on your own. thanks ken

  • Ken Bledsoe Jun 01, 2009

    I guess you don't read your post much.

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2 Answers

Lennox MS8 heat mode never shuts off


Is it the blower that doesn't shut off or the heating unit?

Nov 08, 2014 | Air Conditioners

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...

4 Answers

My gas furnace and heat pump runs at the same time???


its likely the outside control unit board its supposed to only kick on gas only when the temp is at freezing..
or
the inside thermostat is not selected for heat pump, open it an look at the jumper / switch.
or just replace the thermostat , then return it saying you couldnt figure it out. :P
there are a lot more variables here after that you cant know how to check.

Nov 05, 2014 | Honeywell VisionPRO 8000 Programmable...

1 Answer

Aux keeps coming on on regular heat is there something wrong with heat


See if it happens only when your temperature of the room is more than 3 degrees of your setpoint temperature. Since you have a heat pump, the auxiliary (electric heat strips) is use for backup of the heat pump when it can't keep up. The heat pump will run by itself if it can maintain temperature within a couple degrees. If it is too cold outside to handle the load or you set the temperature more than 2 degrees past room temperature, the auxiliary will turn on. The thermostat has a memory of how long it takes to reach desired temperature. If it goes into auxiliary mode trying to satisfy setpoint during the last call for heat, it will start the next call for heat in both aux & heat pump mode until the thermostats algorithm (timed program) allows only the heat pump to run. Not sure if you have an air to air, or geothermal heat pump. The outside air temperature will affect only the air to air system ie. when the temps drop outside, the heat coming out of your vents will be cooler...the air to air systems drops efficiency when the outdoor air drops.

Nov 08, 2013 | Honeywell TH3210D1004 PRO 3000...

1 Answer

REPLACED BOTH ELEMENTS GOT HOT WATER FOR 1 SHOW THEN IT GOT COOLER AND COOLER AND NOW ITS COLD ONLY?


Find a reputable HVAC contractor to do a room by room analysis with heat and cooling loads calculated and units sized and duct requirements and compare to what you have.

The air not being cold is not necessarily an indicator of anything malfunctioning. High efficiency units for instance don't produce cold air.

Since you have had someone look at it, the duct work may be collapsed which restricts air flow or uninsulated which warms up the supply air. Either one is a possibility. Any Cox Cable guys been stompin' around your attic lately? Wouldn't be the first time.

Usually, when the air coming out of the vents is not cold enuf it's because your freon level is low. Probably leaking, but they can usually recharge the freon and it will work for a while. Try another repair company and see if they can recheck the freon level.

We have a high efficiency unit and it produces cold air, so I don't know what previous poster is referring to. Air conditioners are supposed to blow cold air.

Sorry, to tell ya but it is normal if the outdoor temperatures are much below 45 degrees. Below 45 degrees there is little heat outdoors for the heat pump to grab to heat the home so it will run 24/7 and blow cool or cold air. Below 45 the temp of the air coming out the vent will decline and you will get no heat from the heat pump itself as you near freezing.

Your emergency heat or auxiliary heat is electric strip heat. But it only kicks in during normal operation if the temp in the house drops 3 degrees below the setting. (some tstats if can be 5 deg.) Otherwise the heat pump will blow cool or cold air the rest of the time if it is too cold out.

To prevent it from running all the time and blowing cold it is recommended if the temp outside is falling below 45 degrees you should just switch to the emergency heat setting, which shuts the pump outdoors off, and just heat with the electric.

But if there is no heat outside the heat pumps will blow cold. They are the cheapest and most efficient forms of heat but only as long as the outdoor temp is above that 45 deg..

I'm guessing that if you haven't experienced this you live in some place with moderate winter temperatures like in Northern Florida and rarely get very cold winter temps like the freezing you have seen there recently.

It will likely blow much warmer when the outdoor temp rises.


Aug 02, 2010 | Air Conditioners

1 Answer

I recently bought a 4 ton 14.5 SEER Rudd Spilt system using R-410 and matching Rudd furnace. This system replaced a Lennox 10 SEER 4 ton unit. Now that it has gotten hot in Baton Rouge LA 90-93 degrees....


Sounds like the Unit might be low on charge.But without correct readings not sure.
The new unit with 410 will actually cool better due to higher boiling point temp. of freon type.Poor air circulation could also cause problem.Such as dirty filter, too slow fan speed,dirty coil.Also could have obstruction in freon lines either at pump,in line set,or in coil.
Get someone u trust to check it out and ask for their Rudd Dealership Training Credentials.

Jun 15, 2009 | Air Conditioners

1 Answer

My heat is freezing up because it is cold out side,what do I do


Sounds like you having a problem with the defrost board, also check to see if the freeze stat is connected, if not it will not since the coils temp and send a signal to the board to go in defrost and your electric heat strips should kick on if you have them. Depending on what unit you have you be able to which the dip switches to call for defrost at a quicker or longer time depending on the outside temp.

Jan 17, 2009 | Air Conditioners

1 Answer

Janitrol Heat Pump


Jenny,

Sounds to be a system freon leak. The unit and the stat talk to each other and if the temp is not reached and the unit shut down in a set amount of time it turns on the E-heat. Now there are other facts that could be involved, plugged filters, dirty coils inside and out, etc. Check your filters first to eliminate that problem.

Apr 11, 2008 | Ruud UBHC Air Conditioner

1 Answer

Gas furnace wont stay lite


I'm a little confused by your terminology. You are saying you have a pilot lite and electric heat strips? Are you possibly meaning burners? Is the heater running for 2 hours straight without shutting off? how cold is it there? Lastly what temperature do you have the thermostat set at and how close does it get to the temp. before it shuts off?

Dec 16, 2007 | Air Conditioners

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