Carrier 50VQP084-300 Operation, Coaxial Water Pressure Drop, Antifreeze Percentages by Volume

Table 17 — Coaxial Water Pressure Drop

50VQP			PRESSURE DROP (kPa)
UNIT	L/s
		–1 C		10 C	21 C	32 C
SIZE
	0.66	16.5		13.8	8.3	7.6
084	1.00	37.9		31.7	23.4	20.7
	1.32	63.4		54.4	42.7	39.3
	0.76	26.2		21.4	15.8	13.8
096	1.13	55.1		46.9	36.5	33.1
	1.51	89.6		77.2	63.4	59.3
	0.95	14.5		11.7	8.3	6.9
120	1.42	36.5		30.3	24.1	22.1
	1.89	64.8		55.8	46.2	42.7
	1.20	18.6		14.5	10.3	9.0
150	1.76	42.7		35.8	28.2	25.5
	2.39	75.8		65.5	53.1	49.6
	1.32	18.6		15.2	9.6	8.3
168	1.98	42.0		35.8	26.2	23.4
	2.65	71.7		61.3	47.5	44.1
	1.51	28.9		24.1	17.9	15.8
192	2.27	62.0		52.4	41.3	37.9
	1.89	100.6		86.8	71.0	66.1
	2.84	16.5		13.1	9.0	7.6
240	3.78	40.7		33.8	26.9	24.8
	2.39	72.3		63.4	51.7	48.2
	3.53	21.4		16.5	11.7	10.3
300	4.79	48.2		40.7	31.7	28.9
	3.78	85.4		73.7	59.9	55.8

NOTE: If air is purged from the system while using a 250 mm PVC flush tank, only a 25 to 50 mm level drop will be noticed since liquids are incompressible. If the level drops more than this, flushing should continue since air is still being compressed in the loop. If level is less than 25 to 50 mm, reverse the flow.

8.Repeat this procedure until all air is purged.

9.Restore power.

Antifreeze may be added before, during or after the flushing process. However, depending on when it is added in the process, it can be wasted. Refer to the Antifreeze sec- tion for more detail.

Loop static pressure will fluctuate with the seasons. Pres- sures will be higher in the winter months than during the warmer months. This fluctuation is normal and should be considered when charging the system initially. Run the unit in either heating or cooling for several minutes to condition the loop to a homogenous temperature.

When complete, perform a final flush and pressurize the loop to a static pressure of 275 to 350 kPa for winter months or 100 to 140 kPa for summer months.

After pressurization, be sure to remove the plug from the end of the loop pump motor(s) to allow trapped air to be discharged and to ensure the motor housing has been flood- ed. Be sure the loop flow center provides adequate flow through the unit by checking pressure drop across the heat exchanger.

Antifreeze — In areas where entering loop temperatures drop below 4.4 C or where piping will be routed through ar- eas 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) Calculate the total volume of fluid in the piping sys- tem. See Table 18. Use the percentage by volume in

Table 19 to determine the amount of antifreeze to use. Anti- freeze concentration should be checked from a well mixed sample using a hydrometer to measure specific gravity. .

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.

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.

Table 18 — 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 19 — 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

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.

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.

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