During winter time, it's normal for your heat pump to acquire a layer of frost or ice over the coils. Heat pumps are designed to detect things like this and will normally automatically defrost themselves. However, if your appliance completely freezes over so that it's completely encased in thick layers of ice, it could be a sign it's not defrosting like it should. Here are three things that could be causing this particular malfunction.
One thing that cause your unit to freeze up actually doesn't have anything to do with the unit itself, which may be a relief since it can cost up to $1,200 to fix a broken heat pump. If you notice that the ice on your heat pump seems to be thicker on the top than anywhere else on the machine, then you may want to inspect your gutters.
A leaky or damaged gutter may be pouring water onto your heat pump, causing the top to freeze in cold weather, which leads to the rest of the unit icing up and preventing it from defrosting properly. Thus, the first thing you want to check is whether your gutters are in disrepair. If there are icicles forming over the edge or there are holes, then you may want to get your gutters inspected and fixed to see if that solves the problem.
Another reason why your heat pump may not be defrosting properly is because there's isn't enough refrigerant in the system. To defrost itself, your heat pump switches to air conditioner mode with produces heat inside the system and melts the ice. However, refrigerant is required for the air conditioner to work properly. If the system doesn't have enough of the liquid, it can't produce enough heat to eliminate the ice and frost.
This particular problem can be challenging to diagnose, but low refrigerant can make it difficult for your heat pump to produce the desired temperature in your home. If your home doesn't seem to be reaching the temperature on the thermostat in addition to having an iced-up heat pump, you may want to have a professional come out and check the refrigerant levels.
Bad Defrost Timer or Control
A third issue that may be causing the problem is the defrosting timer or mechanism has gone bad. Many models use a combination of temperature sensor and a timer to determine whether the unit is iced over. If the unit is at a certain temperature for a specific length of time, it will switch to defrost mode to melt the ice. Unfortunately, if the timer or thermostat aren't functioning properly, this can cause the unit to not defrost like it's supposed to.
This issue can be difficult to diagnose, so it's best to have a professional inspect the unit and let you know whether this is the problem or if it's something else.
For more tips on dealing with a heat pump that's iced up and won't defrost, contact a local heating repair company.