Hobart HQC200 manual Pipe Sizing Guidelines, Outdoor Condensing Units, Valve and Pressure Settings

PIPE SIZING GUIDELINES

Piping design and line sizing is the responsibility of the installer. The following table can be used as a guideline. The ‘Net Distance to Condensing Unit’ column allows 50% of the Distance for the equivalent restriction to refrigerant flow caused by elbows. We recommend the installer minimize restriction to refrigerant flow by incorporating the following features in their design: Use fewer elbows; use long radius elbows when possible; use 45° elbows instead of 90° elbows, if possible. A vertical suction riser greater than 3 to 4 feet in height should have a P trap at the base to facilitate oil return up the riser. For long vertical risers, an additional P trap is recommended for each 20 feet of riser to assure proper oil movement.

Model		Less Equivalent	Net Distance	Suction Line	Liquid Line
	Total Equivalent Length	Length Allowance
			to Condensing Unit	Size	Size
		for Elbows
	Less Than 45 Feet	15 Feet	Less Than 30 Feet	7/8"	3/8"
HQC135	From 45 to 300 Feet	100 Feet	From 30 to 200 Feet	11/8"	1/2"
	Over 300 Feet	100 Feet	Over 200 Feet	13/8"	1/2"
	Less Than 75 Feet	25 Feet	Less Than 50 Feet	11/8"	1/2"
HQC200	From 75 to 375 Feet	125 Feet	From 50 to 250 Feet	13/8"	1/2"
	Over 375 Feet	125 Feet	Over 250 Feet	15/8"	5/8"

Additional information is available from your compressor manufacturer's system design manual.

OUTDOOR CONDENSING UNITS

Outdoor condensing units are equipped with weather resistant outdoor covers, crankcase heaters and head pressure valves to control the flow of refrigerant through the condenser.

Refrigerant charging of the system in ambients above 70°F requires additional charging equal to the pounds necessary to flood the condenser under low ambient conditions, as defined in the chart below:

MODEL	CONDENSING UNIT	APPROXIMATE ADDITIONAL
	(HP)	R-404A CHARGE
HQC135	3 or 31/4	8 lbs
HQC200	5	15 lbs

Charging of the system with refrigerant in ambients below 70°F requires caution to prevent overcharging since the pressure control valve will already be partially functioning and the amount of additional charge must be determined.

VALVE AND PRESSURE SETTINGS

LOW PRESSURE CONTROL SETTING

(Refrigerant R-404A)
Low Pressure Cut-In	30 psig
Low Pressure Cut-Out	10 psig
The ideal superheat at the evaporator outlet is 8 – 10°F.

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