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Denver Air Conditioning Company: Installing a Hard Start Kit for your AC

by Weatherwise on 05/22/11

Here's what you can do if your air conditioner compressor does not start:


When an HVAC service company troubleshoots a  compressor that will not start, the service technician should begin by measuring the amp draw of the compressor. The AC contractor will install an amp probe around the common motor winding wire of the compressor and try to engage the starting contactor. The amount of current measured in amps will be displayed on the technician's meter showing how many amps the compressor pulls while trying to start. The air conditioning equipment should have a data plate from the manufacturer listing the run load amps (RLA) for the compressor and the lock rotor amps (LRA) of the compressor.  A compressor that pulls LRA will either trip the breaker or lock out internally.  

Note:  If a compresser trips the breaker instantaneously upon start up the Denver air conditioning repair contractor should test the compressor motor windings to see if they are grounded.  This is done by checking continuity between the motor windings and ground.  The best place to check for grounding is on a clean piece of the condenser's copper coil.  No repairs can be made if the compressor is grounded.  The compressor or entire condenser needs to be replaced. 

Note:  An experienced Denver HVAC company will check to see if the compressor is hot.  Many compressors come equipped with an internal thermal overload, which opens up the motor windings.  Cooling off the air conditioner compressor with a water hose for 10 to 20 minutes can often reset the thermal overload.  If it resets the compressor will likely start.  The ac repair technician will need to locate the reason why the compressor has overheated.  This is usually contributed to a defective fan motor or dirty condenser. 

The run capacitor of the compressor now needs to be tested.  Check to see if the capacitor is rated within 10% of the microfarad design listing according to the equipment manufacture.  Any capacitor that has lost more than 10% from its original capacity needs to be replaced.

If the compressor is not grounded and the run capacitor is ok, then it is time for one last shot at starting the compressor.  This is done by installing a potential relay and start capacitor.  The industry term for this is known as a hard start kit.  This hard start kit works by allowing an excess amount of voltage to the starting motor windings of the compressor.  After a starting boost has been supplied to the compressor motor windings, the potential relay will close allowing the compressor to run on its voltage supply from the contactor and run capacitor.  Think of it as an old car that wouldn't start unless you got it rolling and then jumped in and started it.  Those were the days. Once a compressor has received enough starting torque it will often run without problem.  

It is important to note that a hard start kit is not a repair as much as it is a band aid. When the compressor motor windings get aged to the point when the start assist is needed, the air conditioning compressor is limited on its lifespan. The long term fix is to replace the compressor or condenser.  As this is not always practical, a hard start kit is a good alternative.  There is no certainty on how long a hard start kit will be able to overcome the diminishing status of the compressor's motor windings. 

Installing a hard start kit on you air conditioner before the compressor has a hard time starting is highly recommended.  Some high efficiency ac systems come supplied with the hard start kit from the manufacturer.  The fact is that a compressor that starts easy with a low amp draw will be more efficient and last much longer.  

Weatherwise wants to earn your business as the best air conditioning company Denver has to offer.  With our upfront and flat rate pricing we can't be beat. Weatherwise guarantees all repairs made for one full year.  Some Denver contractors try to sell this guarantee as an upgrade.  We offer no gimmicks or cheap tricks. We know honest and fair pricing is what you want and deserve. For fast and reliable heating and air conditioning service, call today.



HVAC service contractor: Air conditioning repair Denver

by Weatherwise on 05/15/11

Thank you for visiting our Weatherwise service tips and troubleshooting advice blog.  Weatherwise serves the entire Denver metro area for all your Denver air conditioning repair and Denver furnace repair needs.  Visit our home page and coupons page for special discounts for all your heating and cooling service needs.

Troubleshooting a condenser that does not start:  Here are some practical diagnostic steps to get to the cause of the air conditioning failure fast.

1. As the air conditioner system is divided into two separate sets of voltage.  The control voltage is a low voltage signal that comes from a step down transformer in the furnace.  The control voltage is then sent through the thermostat to the operating mechanical device to be started.  Start by checking for 24 Volts at the incoming thermostat wire to the condenser. If you do not have 24 Volts here, then the service technician will need to check for 24 volts at the furnace terminal board, circuit board, transformer and thermostat.

2. If 24 volts from the control circuit is present at the ac condenser, then the repair technician needs to check for 24 volts at the control side of the contactor. The contactor is the mechanical switch that allows the high voltage to flow to the air conditioner motors to start them.  If there is 24 volts at the contactor then the low voltage control circuit for the air conditioning system is operating correctly. From this point the HVAC repair contractor will need to shift his focus to the high voltage part of the air conditioning operating system.  If there is no low voltage at the contactor, but it is present at the incoming control wiring, then a safety device in the condenser most likely has disabled the series control circuit.  These safety controls open up when a temperature or pressure problem has been detected.  This protects additional motors from burning up and causing catastrophic damage to the air conditioning system.  These safeties limit the amount of repairs to be made.

3. Start checking the high voltage, which is typically 220-240 volts for a residential condenser.  The first place to check is at the line side of the contactor. If there is no 240 volts here, then the technician will need to start looking at fuses in the ac service disconnect and check to see if the breaker in the electrical panel for the air conditioning condenser has tripped.  A tripped breaker or blown fuses is typically a sign of a compressor over amping on start up.  Some compressors can be boosted to start with less torque by adding a start capacitor and potentially relay known in the HVAC industry as a hard start kit.  If the hard start kit does not reduce the starting amps of the compressor, then the compressor will likely need to be replaced.  A compressor that pulls excessive amps and locks out internally or trips the breaker is said to have failed on lock rotor amps.  The lock rotor amps should be labeled on the condenser's data plate.

4. If high voltage is present at the line side of the contactor, then the service contractor should check the load side of the contactor for 240 volts.  If there is 240 volts, then the next step should be to disable the 240 volts at the service disconnect.  This will allow the Denver air conditioning repair technician to safely check the run capacitors for the compressor and the fan motor.  It is common for a dual run capacitor to fail, causing both the compressor and fan motor not to start. The repair contractor should check the capacitors by measuring the microfarads of the capacitors.  Any respectable Denver air conditioning repair contractor should have all there techs equipped with a meter to measure microfarads. Sometimes a run capacitor has internally overheated causing it to expand.  This is a simple visual inspection.  An experienced hvac contractor can see if a capacitor has a beveled head where the terminal wires are connected. 

5. If it has been verified that there is no 240 volts at the load side of the contactor and there is 24 volts present at the control side of the contactor, then the contactor will need to be replaced.  

This covers some of the basic air conditioner repair tests when the condenser of the air conditioning system does not start.  Not all possible failures have been discussed here, but following these steps should get a Denver HVAC contractor going in the right direction.  Please visit our facebook page for up to date and current seasonal discounts.  Weatherwise strives to be your first choice for all your air conditioning repair and furnace repair needs in the Denver metro area.  We are available 7 days a week.  If you need service in Arvada, Highlands Ranch, Aurora, Broomfield, or anywhere in the local area we are prepared to provide you with the best HVAC repair Denver has to offer. 

AC Repair Denver: Troubleshooting R-22 Refrigerant Pressures

by Weatherwise on 05/09/11

The air conditioning pressures in the Denver area are slightly different than lower elevation ac systems.  The pressures are basically the same, but the thinner air will cause the operating pressures of an air conditioner to have a reduction in pressure.  R-22 refrigerant is the most common refrigerant currently used in the ac market.  Newer systems will use R-410a refrigerant, which has been classified as environmentally safe for the ozone.   Troubleshooting each type of refrigerant is different, so these examples of refrigerant pressures will be mostly used for R-22 ac service and repair.  Here is a list of the most common causes of failure based on low side suction pressure and high side head pressure.


1. Low Suction Pressure and Low Head Pressure
    a. Low refrigerant
    b. Dirty Evaporator Coil
    c. Low refrigerant and Dirty Evaporator Coil

2. High Suction Pressure and High Head Pressure
    a. Dirty Condenser Coil
    b. Excess refrigerant

3. Low Suction Pressure and High Head Pressure
    a. Restriction in thermostatic expansion valve (TXV)
    b. Restriction in piston metering device
    c. Restriction in liquid line drier
    d. Restriction in evaporator coil
    e. Restriction in lineset

4. Very High Suction Pressure and Moderate Head Pressure
     a. Bad compressor valves
     b. Bad compressor motor windings

5. Normal Suction Pressure and Normal Head Pressure, but low temp drop across evaporator
    a. Dirty condensor and low refrigerant

6. High Suction Pressure and Normal Head Pressure
    a. Check to see if heater is on at the same time as the air conditioner

Not all air conditioning pressure symptoms are the same for all failures, but this can get an HVAC technician going in the right direction.  Learning how to analyze refrigerant pressures can be challenging.  It is often necessary to further monitor air conditioning system pressures by calculating the superheat and subcooling of the air conditioning system.  This additional information can enable an HVAC contractor to confirm the diagnostic.  

Weatherwise strives to be the best heating and air conditioning contractor Denver has to offer. We will provide a 100% accurate diagnostic on our first visit.  In fact, customers will never pay for an incomplete or wrong diagnostic service call.  Weatherwise believes that customers should only pay for complete heating and air conditioning service and repairs.   Denver air conditioner repair and Denver heater repair are our specialty.  For the best heating and air conditioning contractor in Denver call Weatherwise today.  We are available 24/7 for all your HVAC repair needs.

Air Conditioning Repair Denver: Dirty Condenser Coil

by Weatherwise on 05/03/11

    A dirty condenser coil can cause catastrophic failures to your air conditioning system.  The fan motor on the condenser pulls the outdoor ambient air through the metal fins of the condenser to cool off the refrigerant after it has been superheated by the compressor.  This process transfers the heat in the superheated refrigerant to the outdoor air.  The air conditioning system needs to have the proper refrigerant state, temperature, and pressure to properly function.     When the condenser coil is obstructed by dirt, grass, cottonwood, or loose debris the amount of airflow crossing over the condenser coil is restricted. A condenser coil with a severe case of bent fins can cause the same restriction.  Bent fins can be straightened with a fin comb.  The fins won't look pretty, but better airflow is what is important.  The average residential condenser can be cleaned by the homeowner with a garden hose and water, but you need to make sure the high voltage power is disconnected. 
    When the condenser coil has not been properly maintained, it is sometimes necessary to disassemble the panels of the condenser to gain access to the condenser coil to clean.  This often includes disconnecting the electrical and removing the condenser fan to clean the unit from the inside. This also enables the air conditioning repair technician to remove any loose debris at the bottom of the air conditioner.  This step is important to make sure loose debris does not get sucked back up into the ac system after it has been cleaned. In severe cases it is necessary to clean the air conditioner condenser coil with outdoor coil cleaner.  Many contractors use acidic coil cleaner.  This is not recommended to clean the air conditioner as it burns the skin and is harmful to the environment.  A biodegradable cleaner is a better and safer choice.
    When the air conditioner head pressure gets higher than normal from a restricted condenser coil, several things can happen.  The condenser motor begins to run at a higher amperage.  This causes the motor to overheat, and eventual failure.  The motor windings are rated to run at a specified run load amperage.  If the air conditioner is not equipped with a high pressure safety device, and it continues to run with a restricted condenser coil or seized fan motor, the motor windings in the compressor can overheat and cause the compressor to fail.  If the fan motor and the compressor are both running hot they can cause the run capacitors to overheat as well.  When the condenser coil is restricted and the air conditioning system is running hot, the refrigerant will not be able to be cooled from a superheated vapor to a liquid.  With no refrigerant heat transfer made, there will be no cooling. 
     Cleaning the condenser coil of your air conditioning system can greatly save a homeowner many costly repairs.  The outside air conditioner is not equipped with filter protection.  In the Denver area Weatherwise can perform a complete tune-up and inspection of your air conditioning system.  Visit our coupons page or facebook page for seasonal discounts.  Weatherwise is a premier Heating and Air Conditioning Denver Contractor.  Our company will provide you with the best service in Denver.  We look forward to earning the right to be your first choice for Denver Air Conditioning and Heating repair.

Air Conditioning Repair Denver: AC Blows Warm Air

by Weatherwise on 04/25/11

When the blower motor in your furnace runs but blows warm air, there are several failure possibilities. Your split air conditioning system in the Denver area consists of three main pieces of equipment.  The blower in your furnace circulates air across the evaporator coil into the home’s living space.  The outdoor condenser compresses the refrigerant and pushes the refrigerant indoors to the evaporator coil.  The refrigerant is forced through a metering device into the evaporator coil, where the heat in the return air is absorbed directly into the refrigerant.  Your air conditioning system doesn’t really make cold air, but rather it removes the heat from your home’s air. Start diagnosing this condition with the following steps.


Check to see if the outdoor unit / condenser is running


  1. Check high and low voltage power
  2. Check the compressor
  3. Check the condenser fan motor
  4. Check the controls and capacitors


Check AC refrigerant pressures


  1. Measure the high side pressure
  2. Measure the low side pressure


Check air conditioning system for leaks if operating pressures are low


  1. Look for oil spots on condenser coil and piping
  2. Leak check condenser and evaporator with electronic or other leak detection tools


Taking these steps will get an HVAC technician going in the right direction to troubleshoot your Denver air conditioning repair.


If you need professional air conditioning repair service today call Weatherwise.  Our company looks forward to doing business with you.

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