Carrier 50HQP072-120 specifications Operation, Units with Aquazone Complete C Control

or before access to all connections is limited. Test pressure may not exceed the maximum allowable pressure for the unit and all components within the water system. Carrier will not be responsible or liable for damages from water leaks due to inadequate or lack of a pressurized leak test, or damages caused by exceeding the maximum pressure rating during installation.

Antifreeze — In areas where entering loop temperatures drop below 4.4 C or where piping will be routed through areas subject to freezing, antifreeze is needed.

Alcohols and glycols are commonly used as antifreeze agents. Freeze protection should be maintained to 8.3° C below the lowest expected entering loop temperature. For example, if the lowest expected entering loop temperature is –1.1 C, the leaving loop temperature would be –5.6 to –3.9 C. Therefore, the freeze protection should be at –9.4 C (–1.1 C – 8.3 C = –9.4 C).

IMPORTANT: All alcohols should be pre-mixed and pumped from a reservoir outside of the building or intro- duced under water level to prevent alcohols from fuming.

Calculate the total volume of fluid in the piping system. See Table 12. Use the percentage by volume in Table 13 to deter- mine the amount of antifreeze to use. Antifreeze concentration should be checked from a well mixed sample using a hydrome- ter to measure specific gravity.

FREEZE PROTECTION SELECTION — The –1.1 C FP1 factory setting (water) should be used to avoid freeze damage to the unit.

Once antifreeze is selected, the JW3 jumper (FP1) should be clipped on the control to select the low temperature (antifreeze –12.2 C) set point to avoid nuisance faults.

Cooling Tower/Boiler Systems — These systems typically use a common loop maintained at 15.6 C to 32.2 C. The use of a closed circuit evaporative cooling tower with a secondary heat exchanger between the tower and the water loop is recommended. If an open type cooling tower is used continuously, chemical treatment and filtering will be necessary.

Table 12 — Approximate Fluid Volume (L)

per 30 M of Pipe

PIPE	DIAMETER (in.) [mm]		VOLUME (gal.) [L]
Copper	1	[25.4]	4.1	[15.5]
	1.25 [31.8]		6.4	[24.2]
	1.5 [38.1]		9.2	[34.8]
Rubber Hose	1	[25.4]	3.9	[14.8]
Polyethylene	3/4 IPS SDR11		2.8	[10.6]
	1	IPS SDR11	4.5	[17.0]
	11/4 IPS SDR11		8.0	[30.8]
	1/2 IPS SDR11		10.9	[41.3]
	2	IPS SDR11	18.0	[68.1]
	11/4 IPS SCH40		8.3	[31.4]
	11/2 IPS SCH40		10.9	[41.3]
	2	IPS SCH40	17.0	[64.4]

LEGEND

IPS — Internal Pipe Size

SCH — Schedule

SDR — Standard Dimensional Ratio

NOTE: Volume of heat exchanger is approximately 3.78 liters.

Table 13 — Antifreeze Percentages by Volume

	MINIMUM TEMPERATURE FOR FREEZE
ANTIFREEZE		PROTECTION (C)
	–12.2	–9.4	–6.7	–3.9
Methanol (%)	25	21	16	10
100% USP Food Grade	38	30	22	15
Propylene Glycol (%)
Ethanol (%)	29	25	20	14

Ground Coupled, Closed Loop and Plateframe Heat Exchanger Well Systems — These systems allow water temperatures from –1.1 to 43.3 C. The external loop field is divided up into 51 mm polyethylene supply and return lines. Each line has valves connected in such a way that upon system start-up, each line can be isolated for flush- ing using only the system pumps. Air separation should be located in the piping system prior to the fluid re-entering the loop field.

OPERATION

Power Up Mode — The unit will not operate until all the inputs, terminals and safety controls are checked for normal operation.

NOTE: The compressor will have a 5-minute anti-short cycle upon power up.

Units with Aquazone™ Complete C Control

STANDBY — Y and W terminals are not active in Standby mode, however the O and G terminals may be active, de- pending on the application. The compressor will be off.

COOLING — Y and O terminals are active in Cooling mode. After power up, the first call to the compressor will initiate a 5 to 80 second random start delay and a 5-minute anti-short cycle protection time delay. After both delays are complete, the compressor is energized.

NOTE: On all subsequent compressor calls the random start delay is omitted.

HEATING STAGE 1 — Terminal Y is active in heating stage 1. After power up, the first call to the compressor will initiate a 5 to 80 second random start delay and a 5-minute anti-short cycle protection time delay. After both delays are complete, the compressor is energized.

NOTE: On all subsequent compressor calls the random start delay is omitted.

HEATING STAGE 2 — To enter Stage 2 mode, terminal W is active (Y is already active). Also, the G terminal must be active or the W terminal is disregarded. The compressor re- lay will remain on and EH1 is immediately turned on. EH2 will turn on after 10 minutes of continual stage 2 demand.

NOTE: EH2 will not turn on (or if on, will turn off) if FP1 temperature is greater than 7.2 C and FP2 is greater than 43.3 C.

EMERGENCY HEAT — In emergency heat mode, termi- nal W is active while terminal Y is not. Terminal G must be active or the W terminal is disregarded. EH1 is immediately turned on. EH2 will turn on after 5 minutes of continual emergency heat demand.

Units with Aquazone Deluxe D Control

STANDBY/FAN ONLY — The compressor will be off. The Fan Enable, Fan Speed, and reversing valve (RV) relays will be on if inputs are present. If there is a Fan 1 demand, the Fan Enable will immediately turn on. If there is a Fan 2 demand, the Fan Enable and Fan Speed will immediately turn on.

NOTE: DIP switch 5 on S1 does not have an effect upon Fan 1 and Fan 2 outputs.

HEATING STAGE 1 — In Heating Stage 1 mode, the Fan Enable and Compressor relays are turned on immediately. Once the demand is removed, the relays are turned off and the control reverts to Standby mode. If there is a master/ slave or dual compressor application, all compressor relays and related functions will operate per their associated DIP switch 2 setting on S1.

HEATING STAGE 2 — In Heating Stage 2 mode, the Fan Enable and Compressor relays are remain on. The Fan Speed relay is turned on immediately and turned off

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