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Last updated: 25 April 2018

How to Defrost the Heat Pump Manually?

Do You Want to Know What the Heat Pump Defrost Cycle Is?

Heat pumps can often get covered by snow and ice during the winter season. Coil covered by white frost and even light ice during certain weather conditions will not significantly influence the working efficiency of your heat pump. On the other hand, if the entire unit is iced-up, including the top of the unit and the insides of coil for an extended period, it can cause serious damage to the equipment. In order to avoid these problems, it is essential to address the issue as quickly as possible.

Heat pumps will naturally ice-up during the lower temperatures but will, from time to time, go into a defrost cycle to de-ice the coils and keep the running efficiency high. If the ice blocks the coil heat exchange between refrigerant and the outside air cannot occur. Even if the frozen heat pump is always a bad news, this article will point out several easy strategies to safely unfreeze your heat pump with only a few tools.

Read more: Heat Pumps: Power for a Sustainable Future

ToolsHow Does the Defrost Cycle Work?

When a heat pump is iced-up, the reversing valve is energized and switches the system into the air conditioning mode. This might sound confusing, but it is right. In fact, while the outdoor evaporator becomes the condenser, the fan shuts off. This process allows high pressure refrigerant to move through the outdoor coil and melt the ice. At the same time, back-up heat is generated to temper the cold air that blows out from the vents.

Immediately after the outdoor thermostat or sensor reaches a certain temperature the system goes back to normal heating mode. The entire process lasts between 2 and 10 minutes, depending on the equipment. Various heat pumps have different ways of determining when to go to the defrost mode. The newer equipments commonly work based on solid-state control modules with temperature sensors.

If your heat pump is often iced-up during the winter, it is possible that defrosting is not the only problem. Some of the problems that may occur can be fixed by the homeowner while others require a professional service call. Our guide presented below will help you to unfreeze your heat pump, but please note that these are just rough guidelines and that your heating system should be inspected and repaired by the licensed technician. Bear in mind that you should never pick ice off with a sharp object. It may cause serious damage to refrigerant coils and fins.

Read more: The Heat Pump Walkthrough

One8Understand the Problem

Every time when frost occurs, especially during the colder season, your equipment can ice-up. To prevent excessive deposition of ice, most of the pumps work according to temperature based defrost system. The system runs on motorized or either electronic timer. Intervals are set differently depending on manufacturer and model of the heat pump but most commonly, these settings are 30, 60 or 90 minutes.

Process _winter

Two 79Run the Fan

Running the fan is the simplest and often best solution to start. In most of the cases, blowing air will thaw equipment within 60 minutes. If outdoor temperature is extremely low, try setting up the fan on an exhaust setting. Constant fan running will not solve the problem and freezing issues, but it is a good start and a way to keep your heat pump running.

Three 35Move the Sensor

When frost conditions occur, your heat pump needs to work longer in order to eliminate ice. Intermittently, moving your thermostat on the outside portion of the unit may help resolving the problem. If you are going for this option, make sure that you have marked the original position of the sensor so you can adequately replace it. Contrary, a new location can be unfavorable which may cause many hours of error solving and inefficient working. It may even result in stopping the defrosting process that is opposite of desirable effect.

Four 16Manual Defrost

If your unit has defrost option run, it every time when outside conditions cause freezing. The power-saving settings and defrost mode are not going hand in hand. Additionally, they might be a reason for your frosting issue. If your defrost cycle is too short, it can cause freezing and frequent troubles for the owner. The best solution for proper clearance and ventilation is to set up your system as close as possible to manufacturer’s specifications.

Read more: How to Apply for Renewable Heat Incentive (RHI)?