Understanding Why Your Heat Pump System May Form Ice In The Summer

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If you live in an area that has relatively moderate temperatures all year round, then you may not use your heating or air conditioning systems very much. If your HVAC system needs replacement, then a heat pump may be your best option to both heat and cool your home. These types of devices can even reduce your energy costs by as much as 60%. Heat pumps may have an underground component that helps to extract and transfer heat or cool air from the earth to your home. However, some air-source or air-air heat pumps use a simple two-unit system. One part of the system sits inside the home, while the other sits outside of it. This system is much like an air conditioner, and just like an AC system, you may see some ice build up. This can happen in the summer to both the indoor and outdoor parts of the system.

Indoor Ice Build Up

If you see ice building up on the interior or exterior heat pump units during the summer, then this can signify a wide range of problems. However, the issue may be a fairly simple one if you like to keep the AC on when temperatures are cool outside or if you set your thermostat below 70 degrees. Heat pumps work by compressing refrigerant and extracting heat from the air to cool it. The heat extraction happens inside the home so cool air can move through the vents. As the air cools, it leaves behind some condensation. If it is cold outside, then it does not take much effort for the refrigerant to cool the air. Air becomes much colder within a short period of time, and this can cause the condensation to freeze around the refrigerant lines.

If you see ice building along the indoor heat pump unit, then shut off the AC until the temperatures become a bit warmer outside. You can also set your thermostat a bit higher. Try these things to see if the heat pump functions properly without ice.

If you do not want to change your cooling habits, then you will need to speak with your HVAC professional about installing a low ambient kit. A low ambient kit is a type of electric fan cycling kit that controls the speed of the condenser fan. The kit monitors the pressure of the refrigerant and changes the speed of the fan to keep cooling pressure high. This helps to reduce the chances of the cooling coils freezing.

Outdoor Ice Build Up

If you notice ice building on the exterior unit during the summer months, then the problem may be a dirty unit. If dirt and debris build on either the inside or outside of the system, then the coolant may not be able to remove heat from the air properly. The coolant may remain cold as it moves outdoors, and the cold may be transferred to the metal fins that sit very close to the copper refrigerant lines. This can cause a freezing issue, especially if it is humid outside.

It is wise to clean the system. Remove the covers from the indoor and outdoor units. Use a shop vacuum to remove as much debris as possible and then use a damp rag to wipe down the refrigerant coils, fins, fan blades, blower cover, and motors. Allow the ice to melt from the outside unit, replace the covers, and start the cooling system again.

If you notice ice building after you complete the cleaning, then the system may be low on refrigerant or one of the parts of the system may need to be replaced. Speak with your HVAC contractor to schedule a thorough inspection of the unit so the problem can be located. Most part replacement and refrigerant recharge issues will need to be handled by a professional. 

2 June 2016