Lennox Packaged HeatPump Freezing Up

[SteveCC]

I have a Lennox Packaged Heat Pump System from 1995. I live in the Los Angeles area and it has been cold at night down to approx. 32-35 degrees. In the Morning the last few days the Unit has been loud and not working great. I set it at 65 degees at night and 67 degrees in the morning. It was trying to get to 66 this morning when I shut it off. When I went up there this morning the side of the unit where the coil is was all iced up. Is it low on Freon? Or ???

Also, this unit heats part of the house , the other part has a split electric system that replaced a packaged unit.

[superd77]

sounds like you need to call a pro.

it also sounds like its running right.

[SteveCC]

I have a Authorized Lennox guy coming over tomorrow. Just curious what causes it to frost like that.

[Kevin O'Neill]

DEFROST SYSTEM:
A heat pump is a lot like a regular air conditioner, except that it reverses every heating season to blow cold air outside and warm air inside. Because the outdoor coil is getting colder than the air outside in the winter, the outdoor coil can freeze in the winter. This is because the outdoor coil condenses water on it in the winter. Only instead of liquid water running off the coil into a drain line, the moisture freezes onto the coil. The heat pump still operates efficiently with a light coating of frost on it. However, eventually the frost becomes a heavy layer of ice and the efficiency is reduced. This is why heat pumps have a defrost system that regular air conditioners do not have. Heat pumps have either a timer or differential thermostat to initialize the defrost cycle. When defrost starts, your heat pump will do some very strange things. This is especially true if you are used to a different type of heating system, such as gas or oil forced air.
The first thing you will notice when the system goes into defrost is a “Whoosh” noise, like the air being let out of a tire. Then the outdoor fan will stop. After a short while a vapor cloud will start to rise from the outdoor unit. We have occasionally had customers call the fire department at this time. But this is normal operation for a heat pump. If the vapor cloud is white, then it is just water vapor (steam) coming from the hot outdoor coil. Only if the cloud is black is it smoke. (Then you can panic!) The compressor noise will usually get louder during the defrost cycle than during normal operation.
What is happening during the defrost cycle is that the reversing valve has switched back to cooling mode so that the outdoor coil will get hot. The outdoor fan has shut off so that the outdoor coil gets hot faster because no air is blowing across it. Then the auxiliary strip heat comes on so it does not blast you with cold air coming out of the supply registers. You will also see water running off the outdoor coil. This is not a leak, just normal operation.
The defrost cycle normally lasts up to ten minutes. Then the heat pump resumes normal operation. The outdoor fan will come back on. The white vapor cloud above the unit may get really huge. The reversing valve will switch back to heating mode with another “Whoosh” and the auxiliary strip heat will go off after a short delay.

I hope that helps.

[SteveCC]

Thanks for Info !!!!!!!!







DEFROST SYSTEM:
A heat pump is a lot like a regular air conditioner, except that it reverses every heating season to blow cold air outside and warm air inside. Because the outdoor coil is getting colder than the air outside in the winter, the outdoor coil can freeze in the winter. This is because the outdoor coil condenses water on it in the winter. Only instead of liquid water running off the coil into a drain line, the moisture freezes onto the coil. The heat pump still operates efficiently with a light coating of frost on it. However, eventually the frost becomes a heavy layer of ice and the efficiency is reduced. This is why heat pumps have a defrost system that regular air conditioners do not have. Heat pumps have either a timer or differential thermostat to initialize the defrost cycle. When defrost starts, your heat pump will do some very strange things. This is especially true if you are used to a different type of heating system, such as gas or oil forced air.
The first thing you will notice when the system goes into defrost is a “Whoosh” noise, like the air being let out of a tire. Then the outdoor fan will stop. After a short while a vapor cloud will start to rise from the outdoor unit. We have occasionally had customers call the fire department at this time. But this is normal operation for a heat pump. If the vapor cloud is white, then it is just water vapor (steam) coming from the hot outdoor coil. Only if the cloud is black is it smoke. (Then you can panic!) The compressor noise will usually get louder during the defrost cycle than during normal operation.
What is happening during the defrost cycle is that the reversing valve has switched back to cooling mode so that the outdoor coil will get hot. The outdoor fan has shut off so that the outdoor coil gets hot faster because no air is blowing across it. Then the auxiliary strip heat comes on so it does not blast you with cold air coming out of the supply registers. You will also see water running off the outdoor coil. This is not a leak, just normal operation.
The defrost cycle normally lasts up to ten minutes. Then the heat pump resumes normal operation. The outdoor fan will come back on. The white vapor cloud above the unit may get really huge. The reversing valve will switch back to heating mode with another “Whoosh” and the auxiliary strip heat will go off after a short delay.

I hope that helps.