Thursday, May 20, 2010

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..

Thursday, May 13, 2010

Commercial Refrigerant Phase-Out

Smart commercial HVAC contractors are paying attention to how the phase out of HCFCs will effect their equipment and businesses. Colorado laws are even stricter than most national regulations. This means Denver HVAC and heating and air conditioner repair companies should consider the many applications that currently use R-22 refrigerant that will be phased out. Supermarket refrigerator cases, and walk in freezers, ice cream machines, and vending machines are just some opportunities that Denver HVAC companies should pay attention to. All of these locations are examples of places that will some day need new non HCFC refrigerant.

There are several alternatives to R-22 endorsed by the EPA, although they have varying levels of effectiveness. Each alternative has different end-uses they are most effective in. A good HVAC company needs to consider what alternative to use and how these alternatives may effect existing refrigeration equipment. Air conditioning repair in Denver needs to take into account the area's needs. HCFC production will be halved this year, 2010. This significant production reduction may create a giant supply shortfall. One thing contractors can do is increase unit efficiency by reducing leak rates. Better recovery practices can reduce the need for Denver A/C repair.

Commercial refrigerant replacements have a their own performance positives and negatives. One major problem is the interaction between mineral oil and these refrigerants. Most places will need new equipment married to a specific refrigerant replacement. Equipment owners should be notified of changes in performance caused by these sealants. The complexity of the new systems means that it the responsibility of the Denver air conditioning services contractor to educate themselves so they can inform customers. Then customers should have a review of equipment that does not meet new EPA standards.

For large scale refrigerant refilling, it is important to have a plan in place for replacement. This is a good opportunity for HVAC contractors to show their clients their wisdom and show how they are indispensable. A complete refit needs to condiser reducing leak rates, total equipment replacement or overhaul, and recovery and recycling programs.

Denver HVAC Industry, rising from recession

The Denver HVAC industry is coming back from the recession. Commercial real estate and is starting to move again, and that means large-scale HVAC jobs in Denver. The Denver HVAC industry tends to lag behind the general contractor economy. However the tight credit market is making it hard to invest in large contracts. The heating and air conditioning industry may take over a year to catch up two the economy. However with the economy recovering this is the prime time to invest. Consumer financing can help with the recovery of the business.

Recently, the turndown rates for financing have been high, according to some Denver HVAC contractors. Financing for large scale projects needs to go through before the industry goes back to just furnace repair and air conditioning parts in Denver.

As inventory goes down, the lag time for the industry catch up goes down too. It may require some investment to push units out of the warehouse. Contractors are wary of stocking up too much on HVAC in Denver. On the other hand, you do not want to run out of air conditioning parts in the middle of summer. Otherwise the industry can get into a cycle of the self-fulfilling prophecy as production steps down as inventory falls right in the middle of summer, when air conditioning service is most needed.

For the green industry, the Denver HVAC certification system is a fortress of strength among the economy. The eco focus in Colorado is not going to stop. Denver furnace repair companies are switching from simple repairs to complete energy saving refits. In a slowdown, green technologies are marketed as a way to save money. Going into green cooling, energy efficiency, and eco centric living are a good way to market HVAC.

Monday, May 10, 2010

Performance HVAC boilers

HVAC in Denver
Boilers are one of the oldest forms of heating. For large commercial HVAC heating, boilers are still one of the best options available. The heat generated by boilers is also reported to be pleasant. A boiler brings an even heat unlike the drafty heat of a heat pump. Many powerful Denver HVAC systems use boilers for even heating across large stores, warehouses or hotels. Gas and oil boilers are available. There is little difference in performance from different heat sources, as a boiler is just a pressure system for heating water and transferring that heat. There are many different options for boilers; there are low and high pressure systems, steam and hot water, but all use a system to loop warm water for heat. Boiler repair is relatively advanced work, so be sure to use a qualified Denver furnace repair company. High performance HVAC boilers usually use steam which uses its own pressure to circulate heat in the system.

Boiler control systems have evolved over time. Older Colorado buildings used a dry fired boiler which is dangerous if the water is not kept at correct levels. More advanced digital control and staging systems are used in advanced HVAC systems. Residential boilers use just an aqua-stat, while commercial boilers use complex local controls built into the system.
Multi-Boiler staging uses several boilers according to demand. Cast iron boilers with solid state controls are good choices that measure the change in energy and adjust boiler use accordingly.
Modulating Control limits fuel use by demand.
An older system rarely used on high performance Denver HVAC is simple on-off boiler fire control.
Step up/down systems are slightly more advanced in that they control furnace levels.
Another way to modify firing is through oxygen trim control. This uses a flue to trim excess air when the boiler is not operating full blast.
Excess air regulation control is like a supercharger that maintains a positive air flow for maximum combustion.
More advanced controls combine air and fuel limiters to add safety and increase fuel efficiency when stepping up or down on heating.
Drum level control makes dry fire systems a little safer by monitoring drum water levels.

Consult both the boiler manufacturer and your local HVAC contractor to determine which controls are appropriate for you.

All boilers need a reliable water source. This may be connected to the city system or a dedicated well pump. It is important to maintain a steady water supply to keep boiler water levels at safe limits. Hot water boiler systems need the system to be full of water. Steam systems need t regulate water so there is only steam in the mains, not water. In a cold city like Denver HVAC systems should have a ball valve between the water source and the boiler to stop major leaks.
Colorado code requires all HVAC systems to have a back flow preventer keep the water supply from being contaminated by the boiler. A pressure reducer valve is also needed to make sure the heating system does not fail over a certain PSI. If you are worried that your system is not safe, consider calling in a Denver heating repair contractor to inspect your HVAC for safety and local regulations.

Geothermal Heat Pump Overview

Denver HVAC
A heat pump is basically an air conditioning unit that can both cool when it is hot and heat in cold weather. Geothermal heat pumps are common for HVAC in Denver because it uses a series of closed loop water pipes in the home's foundation, structure or buried underground. These water pipes facilitate heat exchange and work well in basements. Air heat pumps are configured differently. They usually use electric or gas for back up heating. A damaged heat pump may be harder to repair, so make sure you use a trusted Denver furnace repair shop to get it back into working order.

Just as a refrigerator gets hot on the outside as it draws heat out of the cool inside, a heat pump is a giant refrigerator. When it is hot outside, the pump moves heat from the inside to the outside. A normal air conditioner moves heat in one direction, from the inside out, while a heat pump works both ways depending on the temperature and thermostat settings.

Geothermal heat pumps are very popular in Colorado because they use natural heat from the earth. Geothermal systems are very efficient because they take the stable temperature of the earth to work off heat exchange. This stable constant makes it work better than an air to air heat ecxchange. However, you will need to make an investment to have a geothermal pump. A geothermal pump costs thousands of dollars more than an air pump, so consult a Denver heating and air contractor to see what would be most effective for your home or business. The geothermal system is much cheaper to operate and, will last longer. This is good for Colorado businesses trying for that "green" moniker. Some pumps even provide hot water.

Geothermal pumps come in an open and closed loop designs. The system uses two wells and a pump to pull water from the dump and feeder well. Check with a Colorado HVAC contractor to see if this system will work. A horizontal closed loop system has piping buried several feet below the ground. The heat exchange happens between the piping and the ground. Vertical closed loop systems are good for areas with limited land available, like in a city. Holes are drilled in the earth more than a hundred feet deep. Pipes are filled into the holes. In Denver HVAC contractors will not use closed loop systems because it is hard to drill through the granite rocks. The pipes are connected at the bottom of the holes with a U-bend. Some closed loop systems use a pond or lake with pipes buried deep for heat exchange. Water based heat pumps can even use a water tower and boiler. Water temperature can be maintained at a comfortable warm temperature while still providing heating and cooling.

Monday, May 3, 2010

HVAC Maintenance Help

Posted by Denver HVAC Info

HVAC media filters affect the overall conditions of the HVAC systems in your home. For you to get the best performance from the heating and air conditioning equipment installed in your home, check your filters regularly.

Filters for your heating and cooling systems are important because they prevent contaminants from entering the air flow in our air conditioning units. This ensures that the air we breathe in our home is clean and fresh.

Good indoor air quality will make your HVAC units more energy-efficient. We have to optimize the use of our heating and air conditioning units so that we can save on our utility bills.

In these difficult economic times, the money you save from energy costs can be reduced by decreasing your energy consumption. Utility costs are not the only bills we can effectively take care of with well-maintained heating and cooling systems. Potential operating costs and repairs are also avoided if you have heating and cooling systems checked regularly.

When you have your HVAC units monitored by professionals, the media filters of your equipment needs to be checked too. If they need to be replaced, then it is good to do so to prevent spending on more costly repairs. Make sure that you get the right size filters for the heating and air conditioning units you have. They must be compatible with your HVAC equipment for better systems handling.

Maintenance for heating and air conditioning units is important because we want to prolong the lifetime of the equipment we use to create a comfortable and healthy living environment. Our heating and cooling units are efficient when they are clean and at their peak condition

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