The Failure of "Building Star"

After the success of the Energy Star system, some political pundits were pushing for the concept to be expanded to other areas of the US market. The Energy Star system awards electrical appliances that use significantly less energy with a government sponsored distinction notifying consumers of its environment and cost-saving abilities. The role of government in stimulating green businesses has been well established, so new legislation offering federal government incentives for well built buildings had a good chance of being a positive influence, although traditionally building codes were regulated on the state and local level.

Unfortunately, the HVAC industry works off lower paid employees, and the most recent legislative push to establish a "Building Star" system included regulations that made it mandatory to pay construction workers according to federal wage requirements. This legislation could not get the approval of the largest air conditioning trade group: the Air Conditioning Contractors of America because of these wage requirements. For example, many Denver air conditioning companies use immigrant or illegal labor. Without the support of these Denver HVAC companies and the ACCA as a whole, the legislation was doomed to fail.

The Building Star Energy Efficiency Act, as it was to be called would not only reward buildings that comply with the act with official designation, but also offer tax rebates as an incentive.

Some of the special features that a building would have to display to receive loans and rebates included: Mechanical Insulation, Advanced Exterior Lighting, and Envelope and Roof Insulation. These options, as well as incentives for new furnaces, variable speed compressors and heat pumps were popular with Denver air conditioner companies because they include technologies that they are already pushing on customers.

The real deal breaker turned out to be the government wage regulations. Although the Davis-Bacon requirements only require contractors to pay the "prevailing wage," contractors argued that the increase in labor costs would hamper job creation and make the certification much less appealing to most HVAC companies.

Starting Up Your AC in the Summer

After the long winter, being too zealous about starting up the AC can actually lead to AC problems. Let me let you in on a secret, as a 5-year Denver HVAC mechanic: Refrigerant is not needed unless there is already serious damage to the central heating system. I get called to recharge refrigerators and air conditioning units every spring, but in reality, the refrigerant is in a closed loop and cannot leak unless there is damage to system components. Modern air conditioning appliances should not require maintenance. Regular checking and filling of refrigerant increases the likelihood of refrigerant contamination and therefore further damage down the line.
So one thing the average consumer can do before calling an expensive Denver HVAC service company is to start up the central air unit themselves, checking for any problems. This will outline air conditioner startup and common warning signs that you have a faulty AC part.

First turn off the breakers to both the furnace and central air unit. They should be on separate breakers. For safety, before disassembling or servicing any type of machine that is plugged in, turn the power off.

Remove the cover of the furnace or compressor and vacuum the whole area, making especially sure that there are not foreign parts in the fan blades. Then replace a filter with the same one your Denver HVAC technician. Spin the fan with your hand and listen for any cracks or rumbling which may indicate a failed bearing. If you can correctly identify the problem, it can make it much cheaper for a furnace repair company to fix it. Oil the motor and compressor bearings if they have an oil port.
Bearing problems are cheap and easier to fix than replacing an entire compressor.

With the power still off, clean dust and debris from the outdoor unit's electric wiring. Then spray household cleaner on the coil and rinse it off with a hose. Coils are fragile, but will not work properly if clogged with foreign material.
The compressor in the outside unit is very similar to the furnace blower. Check the outside unit fan the same way, checking for cracks or gaps in the fan and fan housing. Then oil the motor and then you are finished with the outside unit.

Then turn back on the power on a warm day to test the system's pressure. Listen for strange sounds then let the system run for a while.
Then check all the air vents in your home. Air vents should be open to let the system to run ventilation at rated pressure.

Many closed vents may increase pressure in the open ones, but this is bad for the air conditioner. Sometimes cooling problems are a result of the return vent and not the ac vents.
Next is a visual check of the outside unit. The unit should blow warm air and have two lines coming out of it. The small line should be warm or room temperature and the large one should be cool. If you have a outside thermometer you can check the temperature differential between the intake air and the air blown out of the furnace. The temperature difference on a well maintained Denver air conditioning unit should be around 15 degrees Fahrenheit.

Fixing Ice Buildup on A/C Units

Ice buildup is an especially nasty problem that can lead to total HVAC system failure. Refrigerants are built to evaporate and condense millions of times over their life cycle, but solidification ruins the system. Especially in the cold of Denver air conditioning companies need to be careful about ice buildup. Especially around unfinished replacement windows, temperature changes can wreak havoc on A/C units. Water vapor is a contaminant in a refrigerant system. All vapor must be eliminated before refrigerant can be added to your central air conditioner. To remove water vapor, Denver HVAC technicians reduce the system pressure to vent vapor and contaminants.

When a HVAC contractor sees a system with excessive water vapor, they may use an alternate method to evacuate the excess water. The multiple evacuation method is only employed by professional Denver HVACR contractors. This method is more effective because three evacuations are run simultaneously with nitrogen to dissipate water vapor.


A step by step guide to the triple evacuation system for air conditioning repair follows.

Attach hoses from manifold gage to low and high sides of the HVAC system.

Connect two hoses to the manifold center port by installing a T-joint.

Attach a vacuum hose to the center T-port and the vacuum pump. Make sure to add an isolation valve if it is not built into the pump.

Use the other side of the T junction to attach a hose to a nitrogen tank.

Use a vacuum gauge attached far away from the pump to monitor your progress.

Open all manifold valves and the vacuum pump. Keep the pressure of the system normal until you open the nitrogen tank.

Turn on the vacuum an run it until the pressure is below 1000 microns.

Close the vacuum pump valve and turn off the pump.

Introduce nitrogen by opening the valve until the pressure manifold shows 5 inches of mercury.

Then shut the nitrogen tank and wait for the nitrogen to mix with the water vapor.

Start the pump again and vacuum out everything until it is at the previous vacuum pressure.

Repeat until there is no more water vapor.

The Refrigeration Cycle

Refrigeration works by mechanically circulating refrigerant through a evaporation and condensation cycle. Low temperatures and pressures encourage evaporation, while condensation occurs in areas if high temperature and pressure. One side of the loop is inside an area of low temperature like a refrigerator, and one side is on the outside air. This two sided design of the loop allows the transfer of heat.

As a basic overview of the mechanics, as the low pressure liquid refrigerant expands at the evaporator inlet, it absorbs heat and evaporates into a low pressure gas. The compressor then pumps the gas through an accumulator which builds pressure for discharge into the condenser.

The accumulator protects the compressor from trying to pump solid or liquid freon. All Denver HVAC systems should come with an accumulator to protect air conditioning compressor life. Compressors are the most commonly ordered part by Denver air conditioning companies. Compressors are especially susceptible to varying load conditions and frequent compressor on/off cycling.

Condensers remove heat from the gas until it condenses back into a high pressure liquid. Some optional parts common in a Denver air conditioner are drain valves, heat exchangers, and liquid line valves.

The expansion device is between the condenser and evaporator. A liquid line strainer should be installed before this part to prevent problems from the buildup of dirt or moisture. The pressure between these valves is maintained by thermal expansion. As the refrigerant liquid is sucked into the evaporator, its pressure drops and the liquid absorbs heat as it expands and evaporates.

Once the desired interior temperature is reached, the thermostat sends a signal to the central air conditioning or refrigeration unit to shut down. The system turns back on when rising heat in the evaporator enlivens the circuit..