About Me

Grinding, Squealing and Screeching: Interpreting the Noises Your HVAC Makes

If something is failing or going amiss with your HVAC unit, chances are, your HVAC unit is letting you know something is not quite right. However, most of the cues come in the form of sounds that many of us may overlook. If you hear your HVAC unit grinding, squealing, screeching or squeaking, it is letting you know it needs help. I was unaware of these cues and overlooked them. It ended up costing me a lot of money in repairs. I want to make sure that does not happen to other people, so I made this website. I hope you learn how to interpret the noises your HVAC unit is making so you can get it the repairs it needs before you incur a costly repair, or worse, permanently ruin your unit for good.

Grinding, Squealing and Screeching: Interpreting the Noises Your HVAC Makes

What Should You Know About Defrost Issues With Your Heat Pump?

by Billie Carlson

Heat pumps are quickly becoming a popular option in the world of HVAC equipment. These systems are effectively reversible air conditioners, allowing you to change the direction of the refrigerant flow during the winter. With the refrigerant cycle reversed, the heat pump can scavenge heat even from very cold air, allowing you to heat your home efficiently through all but the coldest winters.

However, heat pumps are also somewhat more complex than traditional air conditioners, so they can suffer from a few unique problems. Defrosting isn't a concern with a standard air conditioner, but you may need to worry about it with your heat pump. Why does defrosting matter and how can you know if your heat pump has a defrosting issue? This article will explore these important questions.

Why Defrosting Matters 

A standard air conditioning unit's refrigerant cycle uses two separate coils: the indoor evaporator coil and the outdoor condenser coil. You can think of these two coils as entry and exit points for the heat the system carries. The evaporator coil picks up heat from your home and transfers it to the refrigerant, while the condenser coil releases that heat back into the outside world.

Air conditioner manufacturers carefully design their systems to keep the evaporator coil temperature above freezing so that condensate doesn't form ice. However, a heat pump reverses the refrigerant flow, using the outdoor coil to pick up heat and the indoor coil to release it. Since outdoor temperatures are likely already very cold when in heating mode, ice will likely form on the outdoor coil.

Ice is a major problem for any refrigerant-based system since it acts as insulation on the coil, preventing it from absorbing heat. In a worst-case scenario, it can cause slugging, severely damaging your compressor. Heat pumps prevent this by briefly reversing the refrigerant flow (effectively becoming air conditioners again) to defrost the outdoor coils.

What Causes Defrosting Problems

Anything that prevents your heat pump from defrosting will usually cause the system to stop working. You may notice the system short cycling or turning on and off without reaching your thermostat's setpoint. This situation usually occurs when your outdoor coil becomes covered in ice— overworking the compressor and forcing it to shut down.

Defrosting issues can have numerous underlying causes. Modern heat pumps use sensors to trigger defrosting mode, so a faulty sensor may be to blame. There may also be electrical wiring issues or problems with the electronic control board that engages the defrost mode. The valve that switches between heating and cooling (known as a reversing valve) may also be to blame.

Diagnosing a defrost issue with a heat pump can be complex, and using a heat pump that can't effectively defrost itself may cause expensive damage to the system. If your heat pump has short cycles or fails to run, contact a qualified HVAC technician as soon as possible. While many defrost-related issues are relatively cheap and easy to repair, the damage they cause may not be.

Contact a local HVAC service to learn ormea about heat pump repair.