Carrier 50RTG specifications Electrical Wiring, Water Quality Guidelines

Step 7 — Electrical Wiring

To avoid possible injury or death due to electrical shock, open the power supply disconnect switch and secure it in an open position during installation.

Use only copper conductors for field-installed electrical wiring. Unit terminals are not designed to accept other types of conductors.

All field installed wiring, including the electrical ground, MUST comply with the National Electrical Code (NEC) as well as applicable local codes. In addition, all field wiring must conform to the Class II temperature limitations described in the

AB = 452 volts

BC = 464 volts

AC = 455 volts

452 + 464 + 455

Average Voltage =

3

1371

=

3

= 457

Determine maximum deviation from average voltage:

(AB) 457 – 452 = 5 v (BC) 464 – 457 = 7 v (AC) 457 – 455 = 2 v

Maximum deviation is 7 v. Determine percent voltage imbalance.

NEC.

% Voltage Imbalance = 100 x

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Refer to unit wiring diagram Fig. 4 for a schematic of the field connections which must be made by the installing (or electrical) contractor.

Consult the unit wiring diagram located on the inside of the compressor access panel to ensure proper electrical hookup. The installing (or electrical) contractor must make the field connections when using field-supplied disconnect.

Operating voltage must be the same voltage and phase as shown in Electrical Data shown in Table 3.

Make all final electrical connections with a length of flexi- ble conduit to minimize vibration and sound transmission to the building.

SUPPLY VOLTAGE — Operating voltage to unit must be within voltage range indicated on unit nameplate.

On 3-phase units, voltages under load between phases must be balanced within 2%. Use the following formula to deter- mine the percentage voltage imbalance:

% Voltage Imbalance

max voltage deviation from average voltage

= 100 x

average voltage

Example: Supply voltage is 460-3-60.

457

= 1.53%

This amount of phase imbalance is satisfactory as it is below the maximum allowable 2%.

Operation on improper line voltage or excessive phase imbalance constitutes abuse and may cause damage to electri- cal components.

NOTE: If more than 2% voltage imbalance is present, contact local electric utility.

208-VOLT OPERATION — All 208-230 volt units are factory wired for 208 volts. The transformers may be switched to 230-volt operation (as illustrated on the wiring diagram) by switching the red (208 volt) wire with the orange (230 volt) wire at the L1 terminal.

BLOWER SELECTION — All water source heat pumps are factory set with the appropriate motor and sheave combination to achieve the desired airflow performance. Performance is selected by matching the desired performance with the appro- priate region in Tables 4-12. Per the table notes, regions desig- nated by A, B, C and D represent motor drive options.

NOTE: Factory-installed sheaves are field adjustable. Refer to Tables 4-12 for adjustment points.

	Table 2 — Water Quality Guidelines
CONDITION	ACCEPTABLE LEVEL
pH	7 to 9 range for copper. Cupro-nickel 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.
Corrosion*		Max Allowable Level	Coaxial Metal
	Ammonia, Ammonium Hydroxide	0.5 ppm	Cu
	Ammonium Chloride, Ammonium Nitrate	0.5 ppm	Cu
	Ammonium Sulfate	0.5 ppm	Cu
	Chlorine/Chlorides	0.5 ppm	CuNi
	Hydrogen Sulfide†	None Allowable	—
Brackish	Use Cupro-nickel heat exchanger when 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 agitation 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 solution, allowing accurate sulfide determination up to 24 hours after sampling. A low pH and high alkalinity cause sys- tem 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.

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