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This Is Part 2 Of a 4-Part Article:

To See Part 1 Click Here: AlsPlumbing.com Heat Pumps Part 1 of 4

Al’s Plumbing, Heating & A/C in Plano, Texas provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.  Additionally we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard) and Coleman HVAC (same company as York HVAC).

Al’s also provides full service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s is near your home in Plano, Allen, and Frisco.  We service all homes in southern Collin and Denton Counties with no travel charges.

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.  We will arrange an appointment at your convenience and offer 24/7 Emergency Service.

Heat Pump: When You Want One, Normal Operation, Operational Problems, & When Service Is Needed

Part 2 of 4

american standard platinum gold silver series hvac

 

Heat Pump Frosting / Icing (During Winter)  &  The Heat Pump Defrost-Cycle

photo of heat pump

Photo Source: Shutterstock

A Heat Pump outdoor unit will likely form visible light frost or ice at times (when temps are 35 or lower).   This is normal and part of typical Heat Pump operation.  The Heat Pump will melt the frost or ice as needed.

Many service-calls are generated by Heat Pump owners when they discover frost or ice on the outside unit’s coils.  Light frost / ice occurs during normal operation, and the outside unit will melt the frost as needed.

Click Here To See A Heat Pump Defrosting:  Heat Pump Defrosting Itself

As a Heat Pump extracts heat from the outside air, some moisture within the outside-air freezes and freezes on the outdoor unit’s coils. During cold winter months, a heat pump’s outside unit will sometimes be covered with light frost (or even light ice) on the sides — this is normal operation.  The outside unit will go into defrost mode (every 30-60-90 minutes) as needed to melt the frost.

During the Defrost-Cycle, the compressor is running but the fan at the top of the unit does not be run.  This creates heat to melt the frost/ice, and you may see steam rising or water dripping off the bottom edges of the outside unit during the defrost-cycle.  There will be a notably louder Heat Pump noise-level during a Defrost-Cycle (generated by the compressor in the outside unit),

NOTE:  Because the Heat Pump is temporarily in cooling-mode during the defrost-cycle, cold air may come out the vents inside the home.  To compensate, the heat-strip turns on. During the defrost-cycle, air coming out of the vents will be much less warm than during the heating cycle.  The defrost-cycle runs for only a few minutes.

Heat Pumps Are Not All Created Equal For Noise Level While Defrosting

American Standard & Trane Heat Pumps & Central Air Conditioners use their own proprietary ClimaTuff compressor.  Most other brands have a compressor made by Copeland.  Copeland compressors make notably more noise during a Heat-Pump Defrost-Cycle than ClimaTuff compressors.   Defrost-cycle noise can become a concern with neighbors, or if your compressor is located near a bedroom or living room.

Click On These Links To Hear The Difference In Noise-Level During Heat Pump Defrost-Cycles:

  • During Heating & Cooling Modes, the noise-level is much closer between Climatuff and Copeland compressors.  The Db noise-level shown in product literature is during heating or cooling, not the defrost-cycle.
  • You Can Also Add A Compressor Noise Blanket (if one is not present).

  Click On Photo To: View Product, See Details, or Purchase from Amazon.com

SHOWN: A/C  / Heat Pump Compressor Noise-Blanket

Excess Frost Or Ice Indicates The Heat Pump Is Not Working Correctly

We have provided YouTube videos showing normal amounts of frost on a Heat Pump.  Excess frost or ice build-up prevents the transfer of heat from the outside air (into the refrigerant) and prevents proper Heat Pump operation. If it is not serviced promptly, the unit cannot perform as designed, and heating costs will rise dramatically.  If allowed to operate with heavy frost or ice build-up for an extended period of time, the outside unit will likely become damaged.

Click Here To See Frost Build-Up On A Heat Pump That Is Not Defrosting Correctly: Heat Pump Not Defrosting Correctly

If You See:

  • the top of the unit has a heavy coat of frost or ice
  • the coils are encased in ice
  • the entire unit is covered with a thick sheet of frost and / or ice

Your Heat Pump needs serviced.

Heat Pump Troubleshooting For Excess Winter Icing

THE”EXCESS-ICING” PROBLEM MAY BE:

  • The unit is not defrosting. Under normal conditions, your heat pump periodically defrosts as needed.  This heats up the outdoor coils enough to melt any frost and light ice.  Once the outdoor coil reaches around 57 degrees, the defrost-cycle stops, and the system goes back into heating mode.
  • Defrost issues can be caused by faulty relays, controls, or sensors. There could also be a problem with the Reversing-Valve.  This valve reverses the flow of the refrigerant during the defrost-cycle.
  • The reversing valve can fail, or its electrical-connection may stop working.  In either event, the unit is now stuck in heating mode in winter, and cannot reverse the compressor to cooling mode in order to defrost the outside unit.
  • Outdoor fan problem. The fan motor or blades may have failed.  If the fan is not working properly during heating, excess ice accumulates.  A normal defrost-cycle cannot melt that much frost / ice.
  • Low refrigerant.  With low refrigerant level, eventually the charge may become so low that the system is not producing enough heat to melt the frost.   If this is the case, you will also have issues with the unit’s heating ability.  This will cause the back-up electric heat to run and dramatically increases heating costs It also overworks the heat pump and shortens its life.
  • Water may be dripping onto the outside unit from another source. Water constantly dripping on the unit (from leaking gutters, for example) can form a layer of ice on top.
  • If a notable amount of frost or ice remains at the end of a defrost cycle, call for repair.  Thick ice build-up means something is wrong with your Heat Pump.  Many times, the outside unit is not going into the Defrost-Cycle.
  • Until repairs are made, you could also set the system to “Emergency Heat”.  This will shut the Heat Pump off, and the electric back-up heat will heat your home until the unit is serviced.  This will stop the Heat Pump from attempting to run with excess frost / ice build up.  Call for service to get your unit operational again.  Heating with the electric back-up heat can be up to three times the cost of the Heat Pump.

Issues That May Be Normal & Problems Requiring Service

Heat Pump Is Constantly Running In Winter – Normal Operation

During very cold weather (below freezing temps) a Heat Pump may run constantly.  This is normal and how it is designed to operate. Heat pumps create notably lower output-heat temperatures than a furnace, so they must run longer.  The colder the outside temperature, the more the Heat Pump must run because the outside air contains less heat for the outside unit to extract.

A “Running Constantly” Problem May Be Due To:

dirty air filter on left. New air filter on right.

Photo Source: CanStockPhoto

SHOWN: Clogged Furnace Filter On Left.  New Filter On Right.

  • a clogged furnace air-filter
  • low refrigerant level
  • the HVAC System is dirty (inside and / or outside) and running poorly as a result
  • a poorly insulated home is creating too much heating-demand
  • the HVAC System is too small for your home

NOTE: If the outside temperature is in the mid 30’s or higher, and the Heat Pump is running all the time, you likely need service.

NOTE: If your attic does not have at least R-38 Insulation (roughly 12″ of blown insulation) — you are over working your HVAC System and spending more than necessary to heat and cool your home.

Heat Pump Is Blowing Air That’s Not Warm Enough To Heat The House

In the winter, a heat pump periodically goes into “defrost mode” and temporarily blows barely warm air inside the home.  This is normal, and occurs because the Heat Pump switched to cooling mode to in order to defrost the outside unit.  During this time, the electric back-up heat may turn but air coming out the vents will be only a little warm.

NOTE: Check to see if the outdoor unit’s compressor is running and fan on top is not running (that means it’s defrosting).

 

Another Issue That Can Cause The System To Blow Air That’s Too Cool To Heat The Home (Normal Operation)

The outside temperature is too cold.  Cold air has less thermal-energy (heat) available.  The colder the temperature becomes, the less heat in available (in the outside air) for your heat pump to extract.

In very cold weather, a heat pump may deliver warm air at only 85-95 degrees (which is warm enough to heat your home).  As compared, a gas or electric furnace produces temperatures of 130°F-150°F.  Compared to a furnace, the heat pump’s output-air may not feel warm enough (though it’s working correctly & able to heat your home).

TIP: Measure the temperature of the air at the ducts before calling for service.

  • NOTEBack-Up Heat will operate (only as needed) during very cold weather.
  • NOTE:  With a Heat Pump, You Must Raise The Thermostat TWO (2) Degrees To Get The Back-Up Heat To Turn On.   When the outside temp is mid 30’s or higher, you should not need to raise the thermostat more than 1 degree for more heat (as only the Heat Pump typically produces all heat).
  • NOTE: Any time you want the home to heat up faster, raise the thermostat 2 degrees to turn the back-up heat on.   You will get warm faster, but the cost of heating increasing notably while the back-up electric back-up heat is running.  Note: During this time, both the Heat Pump + Back-Up Heat will be running.

 

Restricted Air-Flow To Outside Unit

Blocked air-flow to the outside unit will cause the heat pump to run longer, work harder and produce less heat.   It also causes condensation and moisture to collect around the coils. The chances of your heat pump freezing are notably increased if air-flow is restricted (often due to overgrown landscaping).

Click Here To See Landscaping Growing Too Close To Heat Pumps: Overgrown Landscaping Blocking Heat Pump Air Flow

 

Your heat pump needs a tremendous amount of air-flow in order for it to work properly, as it extracts heat from the outside air to heat your home.  The amount of air-flow required by a heat pump (heating or cooling) is 350 cubic feet per minute (CFM) for each ton (ton = 12,000 BTU’s) of capacity.  A 2,000 sq. ft. home needs a 3-ton system. In both heating & cooling modes, just over 1,000 cubic feet of air moves through the outside unit each minute!

When the coils in the outside unit are blocked (or dirty) airflow through them is reduced.  This makes the Heat Pump run longer & harder. 

  • Efficiency of the unit diminishes
  • The system runs longer than it normally would
  • Heating (and cooling) costs rise
  • The Heat Pump runs longer and harder, causing it to wear out sooner
  • Keep the outside unit’s coils clean
  • Maintain a minimum of 24″ between the outside unit and any nearby obstruction such as a building wall, shrub, or fence.

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Al’s Plumbing, Heating & A/C in Plano, Texas provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.  Additionally we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard) and Coleman HVAC (same company as York HVAC).

Al’s also provides full service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s is near your home in Rowlette, Wylie and Murphy.  We service all homes in southern Collin and Denton Counties with no travel charges.

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.  We will arrange an appointment at your convenience and offer 24/7 Emergency Service.

 

This Article Is Continued In Part 3 Of 4