BRC HVAC Best Practices

The best practice guide lines contained below are the recommended and approved methods for trouble shooting and servicing all HVAC systems (R-22, R-134A, and R-410A) within the boundaries of all Blue Ridge Properties.

Company Philosophy;

Provide our customers with quality worry free heating and cooling systems. Perform quarterly and annual maintenance to our HVAC systems in order to increase the life and efficiency of them. To always troubleshoot and repair when possible and to only replace systems when no further repair can be reasonably made.

Preventative Maintenance

Purpose;

When completed properly, Preventative Maintenance (PM) not only increases the life of an AC system, it also improves unit efficiency and dramatically reduces energy costs.

Quarterly Preventative Maintenance;

This type of maintenance should consist of filter change and adding pan tab to the condensate drain pan. Coils should be inspected when filters are changed and work orders created to clean dirty ones.

Annual Preventative Maintenance;

This type of maintenance should consist of inspections and cleaning of all indoor evaporator coils. All exterior condensing coils should also be inspected and cleaned.

Routine/Annual Inspection of HVAC Systems;

Purpose;

Complete inspections of HVAC systems will assist in diagnosing distressed units and will help us better determine the path of correction and allow us to detect potential problems in the future. Having a formulated inspection process will also reduce the time taken to troubleshoot a HVAC system.

Points of Inspection; (These are in no particular order)

• Check refrigerant in superheat or sub cool, adjust as needed • Ensure all caps/covers are present with o-rings/gaskets attached (replace all missing or broken

caps/covers) • Check the system for Acid, treat as needed (This should be done when replacing any major

component or anytime a system is opened up.) • Check the system for moisture, treat as needed (This should be done when replacing any major

component or anytime a system is opened up.) • Corrosion check (on every inspection) • Check the air flow path (inspect all dampers, main and individual vent) • Check outdoor coil and straighten fins, as needed • Check indoor coil and straighten fins, as needed • Clean and check the condensate pan and drain line, add pan tabs at every filter change • Check duct work for air leaks, where accessible (plenum and main trunk line off of the air

handler.) • Check for proper indoor blower operation • Check for proper outdoor fan operation • Check that the compressor’s power leads are securely fastened (should be done before any

compressor replacement) • Check the compressor’s starting compactor • Check the compressor’s run capacitor under load • Ensure that non functional compressor are inspected/checked for thermal overload prior to

replacement • Measure the compressor current draw • Check for proper operation of the compressor • Check the operation of the resistance heaters • Check the operation of the heat pump 4-way valve • Check the operation of the crankcase heater (if applicable) • Check if the unit is properly grounded • Check if the unit is level and properly mounted • Inspect that all screws/mounting brackets are present and properly attached. (Replace/repair any

missing or broken items.) • Cycle the unit and test for proper operation • Inspect low-pressure safety cut-off switch • Inspect high-pressure safety cut-off switch • Inspect drain-pan safety cut-off switch • Check thermostat

Troubleshooting;

During the troubleshooting process of diagnosing a non functional HVAC system an accurate measurement of system Freon must be obtained to properly determine whether the system is charged correctly. Please use the superheat or sub cool calibration methods. (A detailed description of how to determine operating head pressures for both methods will be attached.) After calculating proper operating pressures, if the result is determined that the system is low on coolant then a leak test must be performed on the entire system. All findings must be logged/recorded in your site Freon log.

Super Heat

Charging By Superheat Procedures; (Please note; that all numbers/pressures are examples and that every system is different and will require these steps in order to charge a system properly)

1. Turn system on and allow it to run for at least 15 minutes or until the pressures are stabilize.

Super Heat 1 - Outdoor Unit Pressure Reading

2. Take a pressure reading on the suction side (low pressure) line. For this example we will use 68 psig as our pressure reading.

3. Take a temperature reading at the Air Handler on the suction line at the evaporator coil. (see the picture below for exact location) You can obtain the temperature reading using an infrared digital thermometer.

Suction Side / Low Pressure Side / Vapor Side

Discharge Side / High Pressure Side / Liquid Side

Super Heat 2 - Indoor Unit Temperature Reading

4. Your temperature for this example is 52 degrees at the evaporator coil.

5. The next step is to convert your pressure reading of 68 psig to the temperature. Take out your Pressure Temperature Chart and locate the type of refrigerant system you are working on. (In this case it will be R-22.) Locate our pressure reading of 68 psia and look at the corresponding temperature. The temperature should be 40 degrees.

6. The last step is the calculation; Take your outdoor temperature (40 degrees) and subtract it from your indoor temperature (52 degrees) and that will give you Superheat.

Evaporator Coil Temperature 52 degrees

Pressure Gauge Converted Temperature - 40 degrees

Superheat 12 degrees

(Your Superheat should always between 12 and 15 Degrees)

Using an infrared thermometer take reading here.

Sub Cool

Charging in Sub Cool; (Please note; that all numbers/pressures are examples and that every system is different and will require these steps in order to charge a system properly)

When properly charging systems with TXV values the sub cooling is the only method available!!

Sub Cool 1 Location of TXV valve

A TXV valve is a metering device for an indoor unit. Systems with a heat pump will either have a sliding orifice or a TXV valve. If you are unsure of whether your HVAC system needs to be charged in Sub Cool please inspect your indoor unit for a TXV valve in the location posted above.

The TXV valve is located on the indoor air handler next to the evaporator coil.

Procedures;

1. Turn system on and allow it to run for at least 15 minutes or until the pressures are stabilize.

2. Install your gauges to the liquid line (high side).

3. Take a temperature of the liquid line (high side) about 4 inches from the service port and record the reading. For this exercise we will use 125 degrees.

Sub Cool 2 - Charging set-up and location for Saturation Temperature

4. Next take a pressure reading from your high side gauge. For this example we will use a reading of 250 psig. Using a pressure chart convert the liquid line (high side) pressure to the saturated temperature and record the saturated temperature. Log the temperature that is located in the R-22 column corresponding to the pressure of 250 psig. For this example the saturated temperature is 117 degrees.

Discharge Side / High Pressure Side / Liquid Side

Suction Side / Low Pressure Side / Vapor Side

Here is the location to take temperature of liquid line using an infrared thermometer.

True suction Port

Sub Cool 3 - Data Plate Located on the Exterior of HVAC Units

5. The last information needed for our calculation is on the data plate on the outdoor condensing

unit. Locate and write the recommended sub cool temperature for this HVAC unit. For this unit 11 degrees is the recommended Sub Cool.

6. Now it is time to calculate our sub cool temperature with the information we obtained above. Take our two temperatures above; the liquid line (high side) temperature of 125 degrees and subtract the saturated temperature of 117 degrees and record the difference 8 degrees. If the difference between the saturated temperature and the line temperature are within +/- 3 degrees of the recommended sub cool temperature then no action is required.

High Side Line Temperature 125 degrees

Saturated Temperature - 117 degrees

Sub Cool Temperature 8 degrees

(Since this is within 3 degrees of the recommended 11 degree temperature no action is required.)

Note: Below 3 degrees you must add Freon & if you are above the 3 degrees you must recover the Freon.

This HVAC unit shows recommended sub cool temperature of 11 degrees.

Acid Testing Freon in HVAC Units

Acid Testing 1 - QwikCheck Acid Test Kit

Purpose;

To indentify whether Freon recovered from an HVAC system can be reused or recycled. This practice should be used whenever any major component is replaced or when Freon is recovered for any reason.

Each Blue Ridge property should have two recovery tanks. One tank should be labeled “Good” (either with permanent marker or with a label that cannot be removed.) and the second tank should be labeled “Bad”.

• Any Freon that fails the acid test should be recovered in the “Bad” tank turned in for recycling when tank reaches maximum capacity.

• Any Freon that passes the acid test should be recovered into the “Good” tank and can be reused over again.

Freon is a precious resource and should not be wasted. Being able to reuse our Freon will help us to prolong the conversion to 410-A units and thus enable us to control expenses for our HVAC equipment.

Acid Testing 2 - Acid Testing location for HVAC Unit

Instructions for Acid Testing

1. Remove tester from package and remove cap from outdoor unit/condensing unit suction port.

2. Place tester over suction port and press until a short burst of Freon is admitted out.

3. Wait 5 seconds and then inspect the testing cylinder.

4. If the testing cylinder remains yellow and shows NO change in color then the Freon is not contaminated and can be recovered into the “Good” tank and reused again.

5. If the testing cylinder changes color (RED) in any portion of the yellow area then the Freon is contaminated and needs to recovered into the “Bad” tank and not used again.

6. Testers can only be used once whether they detect bad Freon or not and need to be discarded after one use.

7. Replace suction port cap.

Major Component Replacement

Procedures;

Non-Operating Compressor/ Indoor - Outdoor Coil / Reversing Valve

1. Complete a acid test by using a qwik-check 5 second acid test kit

2. If no acid is detected recover your refrigerant in a recovery tank for reuse (remember if acids are detected use a separate tank for non reusable refrigerant)

3. After all the refrigerant has been removed and it is pull down to 28.9 inches in microns

4. Remove the component you are to replacing

5. Install the new component brazing each line with 15% silver solder

6. Install a bi-flow drier filter on your liquid line going into the building ( you must install a drier filter anytime you open a system to atmospheric pressure)

7. Pressurize the system with nitrogen to the normal operating pressures @ 75lbs pressure and hold for 15 minutes to check for leaks

8. If pressures holds for the 15 minutes then release the nitrogen into the air ( do not recover the nitrogen into a recovery tank, it contaminates the Freon)

9. After all the nitrogen has been released from the system pull a vacuum to 28.9 inches in microns. Once you have reached the proscribe levels in microns and it holds pull the vacuum for an additional 15 minutes then shut off the vacuum pump and let stand for another 15 minutes to see if the pressures hold

10. If the pressures hold check the data plate on the unit to see how much refrigerant goes into the system

11. Using a scale weight in the proper amount of refrigerant (remember to use your recovered refrigerant first)

12. Turn on the system and let the pressures equalize for about 15 minutes (you may have to add additional refrigerant for 2nd & 3rd floor units or even first floor if the line set is longer than 25 foot.) Your pressures have to be above freezing this can be obtained by using your conversion chart and converting your pressures into temperatures.

13. After the HVAC system is pressurized above freezing or the low pressure cut off allow system to equalize. Then using the Super heat or Sub Cool methods (See attachment Procedures) charge your system to the proper operating pressures.

Properties with Mixed Systems (R-22 and 410-A)

BRC realizes that going forward there will be situations where a property will have various R-22 HVAC systems that will be retrofitted or converted to 410-A systems. We also realize that both R-22 and 410-A HVAC units look very similar in size and style and that there could be a possibility of mixing refrigerants by accident in the future. Below are approved practices that should be implemented on every property that has a mixture of different units. (Whether it is a single 410-A unit or a second phase that is 410-A)

Practices to prevent mixing Freon;

• All 410-A Units, equipment, and tanks need to be identified with the color pink. (The same color as the 410-A cylinders we purchase.)

• Outdoor 410-A units will now be required to have the isolation valve covers painted pink. (These are the brass valve covers located above the liquid and vapor charging ports.)

• Properties that have mixed systems should have a set of gauges for each system and the 410-A gauge set should have pink on hoses or gauges to identify them.

• Properties should be equipped with either dual recovery equipment or separate recovery machines for each Freon. (410-A equipment should be color coded with a pink stripe or dot)

• Separate recovery tanks should be purchased for 410-A, and along with the “Good” and “Bad” labeling they should have a pink spray mark (line or dot) on them.

The new 410-A practices are to be implemented immediately and will be inspected or reviewed during monthly inspections going forward.

(Note; if you are on a property that is 100% 410-A then the color coding will not apply.)