How a Heat Pump Both Cools and Heats a Home

The name “heat pump” is technically accurate, but often a little misleading. Heat pumps actually both heat and cool the home, and indeed they do so using the same basic technology as a traditional air conditioning system. Heat pumps are a convenient way to deal with both our muggy summer and our cold winters here in Frederick, MD with the same basic unit, but it helps if you the homeowner understand a little bit about how a heat pump both cools and heats a home. It starts with the basic technology.

Heat pumps (and most common types of air conditioners, for that matter) used a closed loop system cycling refrigerant gas through a series of valves and coils. The process starts with the compressor, which subjects the gas to a great deal pressure. The pressurized gas then moves to a set of condenser coils, which bleeds the heat out of them and into the surrounding air. (That air can then be blown into the home via a fan.) The process reverts the gas to a liquid state, and the liquid then moves to a second set of valves and coils. The expansion valve releases a set amount of the liquid into a set of evaporator coils, which pulls heat from the surrounding air as the gas reverts to a gaseous state. It then moves back to the start of the loop to begin the process again.

With air conditioners, the loop move in a single direction. The compressor and condenser coils are located on the outside of the home (allowing it to release heated air outside), while the evaporator coils are located inside (allowing it to provide cool air that can be blown into your home with a fan). For heat pumps, the cycle is reversible; the indoor coil system can serve as a condenser in the winter (to provide heat) and an evaporator in the summer (to provide cool air) while the outside coil does the same in the reverse.

It’s an effective system, though like any such system, it takes training and expertise to properly install and maintain. That’s where the experts at Larry & Sons, Inc. come in. We provide many heating services in Frederick, MD and heat pump installation and repairs are part of our standard services. Give us a call today and let us show you how a heat pump both cools and heats a home.

Hedgesville Heat Pump Guide: What to Do About Ice and Snow

It’s very common for heat pumps in Hedgesville to ice over in the winter time. It can be due to freezing temperatures and icing outside or it could be due to constant running of the heat pump or excess moisture on the coils. However, while a bit of ice on the heat pump is relatively normal, the entire unit should never be covered in ice – such a thing is not only hard on the machinery; it can result in no heat for your home.

How to Handle Ice and Snow on the Heat Pump

Should your heat pump become covered in ice or snow in the winter time, there are a few things you can do and some things you should not do. First, check to make sure the problem isn’t related to a broken defrost cycle timer. The heat pump should go into a defrost cycle every 30-90 minutes to keep excess ice from building up. If this doesn’t happen, it should be inspected for a thermostat or sensor problem.

To actually remove the ice from the unit, never use a sharp object to pick the ice clear. You can easily damage the coils or another part of the unit and leave it permanently broken. The best way to remove ice from your heat pump is to rinse it off with a hose – even cold water will remove ice. Just be sure the defrost cycle is ready to come back on so the water used to rinse away the ice doesn’t freeze.

Remember to check your emergency heating source and make sure it is switched on while this is happening. Your heat pump likely won’t work properly while iced over and if it is left in the on position, excess stress on the device will cause damage.

To avoid this kind of damage, turn off the heat pump and turn on your emergency heating source, then clear away the ice and check the defrost timer. If everything works properly, turn the heat pump back on, but if you find any problems, call a professional to do a more thorough inspection of the device before you use it again.

Mercersburg HVAC Repair Question: What Is Refrigerant Pressure and Why Does it Matter?

Refrigerant is often called the “lifeblood” of mechanical heating and cooling devices like the heat pump and air conditioner in your Mercersburg home.  The main function of refrigerant is to transfer heat through a closed loop system. Various heating and cooling (HVAC) components require different operating pressures to move refrigerant and process the “refrigeration cycle.”

In a nutshell, the refrigeration cycle involves refrigerant, which changes from a liquid to a vapor and back to a liquid again by the addition of pressure and heat. In a refrigeration system, pressurized refrigerant passed through an expansion valve into an evaporator and pressure is reduced. The evaporator is a tube which passes by the area to be cooled. When the pressure drops, this liquid refrigerant changes into a vapor, which absorbs vaporized heat from the area around the evaporator. After the heat is absorbed by the refrigerant, it flows to a condenser, where it passes over coils, absorbs heat from the hot vapor, and condenses back into a liquid. The liquid is returned to the compressor and the cycle begins again.

Today’s refrigerants – especially those used in residential applications – are broken down into two different types, labeled R-22 and R-410A. R-22 is made up of a chlorofluorocarbon (CFC) chemical, which has been found to be damaging to the Earth’s ozone layer. It has been replaced by R-410A, which is made up of a hydrofluorocarbon (HFC) chemical and will eventually be phased out by the year 2020. One of the biggest differences between the two are their operating temperatures. HFCs operate at much higher refrigerant pressure.

This change between refrigerants has created some interesting dynamics and challenges for the HVAC trade. Gauges used to check pressure readings have all changed. And mechanical compressors do not operate with a variety of refrigerants, so the compressors and coils need to be swapped out, too. To give you an example, let’s say you are shopping for a new central air conditioner. Chances are, the new air conditioner will run on R-410A. Your old air conditioner ran on R-22. In order to “match” the compressor in the your new air conditioning unit to the existing indoor coil, you will need to replace the coil and the lines running from your outdoor condensing unit to your indoor air handling unit, which is mounted to your furnace.

You don’t have to understand the refrigeration cycle to know that today’s high-pressure HFC refrigerants require different test instrumentation and retrofitted or upgraded mechanical equipment. The change in operating pressure is a small price to pay for a safer environment.

A Question from Marlowe: Why Do Heat Pumps Need Refrigerant?

Despite its name, a heat pump is not designed solely for heating for Marlowe home. In fact, the technology in your heat pump was originally designed for air conditioning and is used today in air conditioners, refrigerators and cooling units in vehicles and airplanes. And the entire process relies on refrigerant – a chemical compound that is compressed and expanded to move energy from one environment to another.

How Refrigerant Makes Heating and Cooling Possible

Your heat pump has multiple components designed to transfer refrigerant from one state to another. The compressor, for example, compresses the refrigerant into a liquid. The liquid is then moved through the expansion valve to the evaporator coils where it expands into a gas. Because refrigerant evaporates at much lower temperatures than water, it does this rapidly and in the process draws heat from the surrounding environment.

That’s how an air conditioner or your refrigerator cool a space. However, in the case of a heat pump, the process can work in both directions. In cooling mode, your heat pump extracts heat from the air going into your home. In the case of heating mode, the heat pump extracts heat from the outside air. Because the heat is transferred into the refrigerant, it can then be recompressed by the compressor. The heat is then is then released in the condenser coils, where the gas returns to liquid state. A blower then distributes air blown across the condenser coils into your home as heat.

Troubleshooting the Process

A heat pump is a complex piece of machinery, but once you know how it works, you can perform quite a bit of troubleshooting should anything go wrong with the device. For example, if you notice cold air coming from your vents, you can check to make sure it isn’t in cooling mode and that there is enough refrigerant in the device.

Keep in mind that if any service needs to be performed on the heat pump involving refrigerant, you should call a Marlowe professional due to the volatile nature of the chemical. In most municipalities, you must have a license to distribute or dispose of refrigerant and even if not, it can be dangerous to both you and the environment.

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