Carrier 50KQL-1PD manual Condensate drainage, Water conditioning, Acoustical design

concealed below ground. The number of loops required de- pends on ground conditions, heating and cooling require- ments, and the depth of each hole.

Hybrid systems — In some applications, it may be bene- ficial to incorporate a cooling tower into the ground loop system to reduce the overall cost. A Hybrid System dis- cards excess heat into the air and increases the cooling performance of the ground loop.

Condensate drainage

Connect the console unit condensate drain to the building condensate drain with a flexible, non-pressure rate plastic hose. Be sure to avoid kinks in this hose to ensure an un- obstructed flow of condensate from the unit to the drain. The condensate hose’s horizontal run is usually too short to pose any drainage problems, however, make sure this line is pitched at least 1 inch for every 10 feet of run (in the direction of the flow.) Avoid low points and unpitched piping since dirt collects in these areas and may cause stop- page and overflow.

Installing a trap or drain in the field is not required unless specified by local codes. The 50KQL units are designated in a blow-thru configuration. The condensate drain pan is located on the outlet side of the blower so that the pressure in the drain pan is higher than the atmospheric pressure.

Water conditioning

In some applications, maintaining proper water quality may require higher corrosion protection for the water-to- refrigerant heat exchanger. Water quality varies from loca- tion to location and is unique for each job. Water charac- teristics such as pH value, alkalinity, hardness, and specific conductance are important when considering any WSHP application. Water typically includes impurities and hard- ness that must be removed. The required treatment de- pends on the water quality as well as system type. Water problems fall into three main categories:

1.Scale formation caused by hard water reduces the heat transfer rate and increases the water pressure drop through the heat exchanger. As water is heated, minerals and salts are precipitated from a solution and deposited on the inside surface of the pipe or tube.

2.Corrosion is caused by absorption of gases from the air coupled with water on exposed metal. Corrosion is also common in salt-water areas.

3.Organic growths, such as algae, can reduce the heat transfer rate by forming an insulating coating on the inside tube surface. Algae can also promote corrosion by pitting.

NOTE: In most commercial water loop applications, Aqua- zone™ WSHP units use copper water-to-refrigerant heat exchanger. Units can also be equipped with a Cupronickel heat exchanger for applications where water is outside the copper heat exchanger’s standard contaminant limits.

	WATER QUALITY GUIDELINES
CONDITION		ACCEPTABLE LEVEL
pH		7 to 9 range for copper. Cupronickel may be
		used in the 5 to 9 range.
Total Hardness		Calcium and magnesium carbonate should not
		exceed 20 grains per gallon (350 ppm).
Iron Oxides		Less than 1 ppm.
Iron Bacteria		No level allowable.
			Max Allowable	Coaxial
		Ammonia,	Level	Metal
			0.5 ppm	Cu
		Ammonium Hydroxide
Corrosion*
		Ammonium Chloride,	0.5 ppm	Cu
		Ammonium Nitrate
		Ammonium Sulfate	0.5 ppm	Cu
		Chlorine/Chlorides	0.5 ppm	CuNi
		Hydrogen Sulfide†	None Allowable	—
		Use Cupronickel heat exchanger when
Brackish		concentrations of calcium or sodium chloride
		are greater than 125 ppm are present.
		(Seawater is approximately 25,000 ppm.)

*If the concentration of these corrosives exceeds the maximum allowable level, then the potential for serious corrosion problems exists.

†Sulfides in the water quickly oxidize when exposed to air, requiring that no agita- tion occur as the sample is taken. Unless tested immediately at the site, the sample will require stabilization with a few drops of one Molar zinc acetate solu- tion, allowing accurate sulfide determination up to 24 hours after sampling. A low pH and high alkalinity cause system problems, even when both values are within ranges shown. The term pH refers to the acidity, basicity, or neutrality of the water supply. Below 7.0, the water is considered to be acidic. Above 7.0, water is considered to be basic. Neutral water contains a pH of 7.0.

NOTE: To convert ppm to grains per gallon, divide by 17. Hardness in mg/l is equivalent to ppm.

Acoustical design

Sound power levels represent the sound that the source, the WSHP unit, produces with no regard to attenuation be- tween the source and the space. Acoustical design goals are necessary to provide criteria for occupied spaces. These goals help ensure that people can be comfortable and com- municate effectively over the background noise of the air- conditioning system and other background noise sources.

Acoustical design goals are desirable sound pressure levels within a given conditioned space and are represented by Noise Criteria (NC) curves. Noise Criteria (NC) curve levels represent a peak over a full frequency spectrum. A high value in a low frequency band has the same effect on NC level as a lower val- ue in a high frequency band. It is important that sound levels be balanced over the entire spectrum relative to the NC curve. The lower the NC criteria curve, the more stringent the room acoustical design must be to meet the design goals.

It is important to know how to convert the unit ratings from sound power (Lw) to sound pressure (Lp). This con- version depends on the specifics of the installation’s acous- tical environment. Assessing an area’s acoustical design re- quires that you compare the sound pressure (Lp) with the NC curve for the selected area.

The resulting calculations are compared to the NC curve selected for the area to assess the acoustical design.

Some of the factors that affect conversion of sound power to sound pressure and consequent NC level include:

•Type of acoustical ceiling

•Use of metal or flex duct

•Absorption in the occupied space

•Location in the occupied space

•Open or closed layout plan

•Use of open or ducted returns

•Orientation of unit to occupant

•Use of lined or unlined duct

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