Tip & How-To about Heating & Cooling

DIY Air Conditioning Maintenance- from basic steps to coil cleaning

Want to extend the life of your central HVAC system? Two words come to mind- Preventative Maintenance. An annual service on your equipment can be performed by a professional for a reasonable fee, usually including an annual condenser cleaning, evaporator cleaning on an as-needed basis (the frequency of this depends largely on usage and climate), drain line flush, and worn or old control electronics replacement. Changing filters on a regular schedule is the single most important task in preventative maintenance (PM).

Filters:
There are many options as to which type of filter you use. Hogs hair filters are arguably the cheapest seeing as they are reusable. These have the drawback of OSOM syndrome- out of sight out of mind. As time goes on these become more dirty and catch less. I do not recommend them as they do not protect the system in the long term as well as throw away types. Fiberglass filters are the cheapest of the throw aways. These work fine if changed very regularly, but will not trap smaller particles which will over time find their way to your evaporator coil. I would never allow one of these to stay in my system for more than a month. Pleated filters round out the common filter types. Some of these can cost as much as 10x as the cheaper one- unless your system is engineered to handle extreme hepa filters do not use these. The airflow restriction causes the blower to work at an unnecessary rate and shortens the life of the motor, and can also cause coils to ice over, limit switches in gas furnaces to shut the system down, etc. The best route to go is the cheaper pleated filters, readily available in most sizes. Checking them once a month and replacing at least every 2 months has shown to be the best working solution, although extremely dusty homes may require bi-monthly changing.

Equipment Cleaning:
The 2 components requiring regular cleaning are the evaporator and condenser coils. The outdoor section can usually be cleaned with a water hose and a good spray nozzle. This unit lives outside 24/7/365, so no, a bit of water will not hurt exposed parts while running. This should be performed annually at least, though a quick spray down every few months doesn't hurt. The idea is simply to remove dirt from the coils. While you are at it, all those leaves and such lying in the bottom of the cabinet are not helping anything but the rot of the surrounding metals. The top of most condensers consists of a fan. On these you can simply shut power down to the unit and unscrew the fan housing to get this out of the way. The compressor can be very hot, so watch out not to burn yourself while removing debris.
The other annual necessity is the condensate drain The condensate drain is the line which drains water from the AC unit to the exterior of the home, usually 3/4 PVC pipe. This can be cleared by using pressurized gas (up to 60 PSI) or, my choice, a wet/dry shopvac. Once cleared you can backflush the line from outside with a water hose. The premise is to fill the line completely with water back to the condensate pan, then let it flush itself out using gravity. In doing this one must be careful not to overfill the equipment- water will drain from the unit to whatever lies below it. This technique is something one perfects with experience. Generally 4 or so seconds of having the hose attached to the line using our hand for a seal is long enough to probe the system, incrementing in 1 second intervals each attempt. What you are looking for is gunk in the water which rushes out after you've taken the hose off of the drain pipe. Once gunk (technical term) starts to flow heavily you've figured out how long it takes for the water to reach the evaporator, 2-3 iterations at this interval are usually enough to clear a system adequately.

Cleaning an evaporator:
We've reached the end of the easy stuff- if you don't have a good degree of mechanical aptitude stop now and call a service tech every other year. The evaporator is located inside of air handlers in heat pumps, coil boxes on a ducted side of a furnace, or in mysterious locations inside of packaged units. You may easily locate split coils by following the linesets. Wherever it is, you will need access to both sides of the coils. A quick visual inspection should show a shiny aluminum surface- the luster of a soda can. Anything other than this and the coil should be cleaned. There isn't a safe household version of the chemicals an experienced technician would use, but Simple Green degreaser works well when applied liberally. A pressure sprayer is ideal, but a standard spray bottle can be made to work, though it is much more labor intensive. In cases where the buildup on the coil is minimal and the particles are all small in size a good flush with this solution is sufficient, remembering to rinse with water afterwards. Some coils have larger particles, usually pet hair, forming cakes on the surface. These need to be mechanically removed. A stiff paintbrush or toothbrush can be used to clean these off. Being careful not to bend or break the coil fins, run the surface in the direction of the fins from one side to the other (or top to bottom if you prefer). Once large particles have been removed, another flush with degreasing solution is required. After cleaning a coil, it is always a good idea to run about a gallon of water through the condensate drain to clear biological material from the line. Remember that bent and broken fins are very difficult to repair and if left cause the system to be less efficient. Also remember that the fins on these coils are quite sharp and the copper lines coming in and out of the coil can be quite fragile, so take your time and be careful. There are occasions where extremely clogged coils cannot be simply flushed and brushed. I have been known to cut coils out of systems and take them to a self serve carwash to clean with pressurized water. In these cases even the best service technicians cannot always bring a coil back to life, so it is not something I would recommend ever trying to do yourself.

Blower Wheel:
Over time in very dusty systems the blower wheel can become caked and therefore less efficient. If you notice this upon inspection you would do well to call a competent professional to take care of the problem. The blower motor is not designed to handle moisture and has to be removed from the housing (after housing is removed from unit) before beginning the cleaning. These shafts have a tendency to rust in place and can raise a good number of 4 letter words from even the most experienced professionals during attempts to remove the motor. If you choose to tackle this task sandpaper for the shaft and a good water displacement oil are key to freeing the shaft- do not in any case use a hammer to pound the shaft; you will be finding yourself replacing a not-so-cheap motor.

Replacing worn parts:
I am not going to go into a schedule for this as the system needs are very broad. If the inconvenience of a minor part breaking at 5:30 on a friday afternoon just before a diner party is intolerable for you, I would highly suggest having a service tech come out to replace any minor parts (transformers, contactors, relays, etc) they deem necessary in the units 5th year of service and every other year after this.

The average life of a central system in my region is about 15 years, with the range being about 10-30 years excluding anomalies. I'll say with high confidence that most equipment can serve you for around 20-25 years if properly maintained, and around 10-15 years if completely neglected. Considering the average PM call is around $200.00 (or 3 hrs for the average homeowner) and system changeout around $7,000, it is certainly a wise investment in either your time or money to perform this simple maintenance annually.

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what is hvac


Hi, Hvac that i know is (Heating, Ventilating, and Air Conditioning) refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. Refrigeration is sometimes added to the field's abbreviation as HVAC&R or HVACR, or ventilating is dropped as in HACR (such as the designation of HACR-rated circuit breakers).

HVAC is important in the design of medium to large industrial and office buildings such as skyscrapers and in marine environments such as aquariums, where safe and healthy building conditions are regulated with temperature and humidity, as well as "fresh air" from outdoors.

Heating, ventilating, and air conditioning is based on inventions and discoveries made by Nikolay Lvov, Michael Faraday, Willis Carrier, Reuben Trane, James Joule, William Rankine, Sadi Carnot, and many others.

The invention of the components of HVAC systems went hand-in-hand with the industrial revolution, and new methods of modernization, higher efficiency, and system control are constantly introduced by companies and inventors all over the world. The three central functions of heating, ventilating, and air-conditioning are interrelated, providing thermal comfort, acceptable indoor air quality, within reasonable installation, operation, and maintenance costs. HVAC systems can provide ventilation, reduce air infiltration, and maintain pressure relationships between spaces. How air is delivered to, and removed from spaces is known as room air distribution.[1]

In modern buildings the design, installation, and control systems of these functions are integrated into one or more HVAC systems. For very small buildings, contractors normally "size" and select HVAC systems and equipment. For larger buildings, building services designers and engineers, such as mechanical, architectural, or building services engineers analyze, design, and specify the HVAC systems, and specialty mechanical contractors build and commission them. Building permits and code-compliance inspections of the installations are normally required for all sizes of buildings.[citation needed]

The HVAC industry is a worldwide enterprise, with career opportunities including operation and maintenance, system design and construction, equipment manufacturing and sales, and in education and research. The HVAC industry had been historically regulated by the manufacturers of HVAC equipment, but Regulating and Standards organizations such as HARDI, ASHRAE, SMACNA, ACCA, Uniform Mechanical Code, International Mechanical Code, and AMCA have been established to support the industry and encourage high standards and achievement.


Hope is the one your talking about.

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Feb 14, 2011 | Cell Phones

2 Answers

I have a 2007 rabbit, 2 door with 22K miles. What, if any, maintenance is required other than the annual oil change?


Well, I'm a bit of a ****** for preventative maintenance, mostly because I'm lazy and just want my equipment to work forever. So, here are some things that will be helpful: Around every 10-15k miles, it is best to change out the fluid in the rear differential. That's also a real good time to change manual transmission fluid. 50k is a good time for automatic transmission fluids. 50k is also a pretty good time to drain out your old coolant, and pour some new coolant in. Probably every 500 miles is a good time to take a look at how much brake fluid you have, and how much power steering fluid you have. Every month, no matter how cold/hot, run your heater for 5 minutes, then your A/C unit for five minutes to keep the seals stable. Every now and again, take a peak under your vehicle's frame, check EVERYWHERE for rust. You don't want rust sneaking up on ya'. Look often, and change every 30K miles or so, your brakes, make sure they are in best possible shape. Also, press on your bumper, and let loose. If you're starting to have stability problems (Maybe at 100K miles or so), it is time to check those shock absorbers. There's plenty of stuff to check, but it's mostly preventative. Might get a Chilton-Hayes style manual for your vehicle.

Oct 31, 2010 | 2007 Volkswagen Rabbit

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my older air2 failed, the interior parts corroded


IF the used reg works, at $40 you're likely money ahead. Has the used DualAir you have in mind been looked after lately?

Remember, life support equipment should be WELL maintained and serviced annually by an authorized repair person. What's your live or the life of you buddy worth? Servicing your Air2 would be in the neighborhood of $50, depending on how rotten how many of your corroded parts are. Last I knew, if you buy a Scubapro reg and have it serviced *annually*, as is prudent, the parts are free.

Nov 11, 2009 | Alert Scuba-pro Air 2 Regulator Octo Dive ...

2 Answers

Repair on Datacard sp35 locate in Houston Texas


Do you have found a repairer for your datacard ?

Feb 27, 2008 | Datacard SP35 Printer

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