Carrier 23XRV manual Vent and drain connections, Relief valve discharge pipe sizing, ASME stamping

Application data (cont)

Vent and drain connections

Nozzle-in-head waterboxes have vent and drain connec- tions on covers. Marine waterboxes have vent and drain connections on waterbox shells.

Provide high points of the chiller piping system with vents and the low points with drains. If shutoff valves are provid- ed in the main liquid pipes near the unit, a minimal amount of system liquid is lost when the heat exchangers are drained. This reduces the time required for drainage and saves on the cost of re-treating the system liquid.

It is recommended that pressure gages be provided at points of entering and leaving liquid to measure pressure drop through the heat exchanger. Gages may be installed as shown in Pressure Gage Location table. Pressure gages installed at the vent and drain connections do not include nozzle pressure losses.

Use a reliable differential pressure gage to measure pres- sure differential when determining liquid flow. Regular gag- es of the required pressure range do not have the accuracy to provide accurate measurement of flow conditions.

PRESSURE GAGE LOCATION

NUMBER	GAGE LOCATION
OF
	(Cooler or Condenser)
PASSES
1 or 3	One gage in each waterbox
2	Two gages in waterbox with nozzles

Each heat exchanger and economizer (if equipped) is ASME ‘U’ stamped on the refrigerant side of each vessel.

Relief valve discharge pipe sizing

See page 21 for number of relief valves.

Relief valve discharge piping size should be calculated per the current version of the ASHRAE 15, latest edition, code using the tabulated C factors for each vessel shown in the table below.

23XRV RELIEF VALVE DISCHARGE PIPE SIZING

		VESSEL	RELIEF
			VALVE	FIELD
HEAT	FRAME	REQUIRED
			RATED	CONNECTION
EXCHANGER	SIZE	C FACTOR
			C FACTOR	SIZE (FPT)
		(lb air/Min)	(lb air/Min)
	30 to 32	43.4	70.8	11/4″
	35 to 37	49.5	70.8	11/4″
COOLER	40 to 42	50.4	70.8	11/4″
	45 to 47	57.4	70.8	11/4″
	50 to 52	53.7	70.8	11/4″
	55 to 57	61.1	70.8	11/4″
	30 to 32	41.4	70.8	11/4″
	35 to 37	47.1	70.8	11/4″
CONDENSER	40 to 42	47.1	70.8	11/4″
	45 to 47	53.7	70.8	11/4″
	50 to 52	51.2	70.8	11/4″
	55 to 57	58.3	70.8	11/4″

ASME stamping

All 23XRV heat exchangers are constructed in accordance with ASHRAE (American Society of Heating, Refrigerat- ing, and Air Conditioning Engineers) 15 Safety Code for Mechanical Refrigeration (latest edition). This code, in turn, requires conformance with ASME (American Society of Mechanical Engineers) Code for Unfired Pressure Ves- sels wherever applicable.

Carrier further recommends that an oxygen sensor be installed to protect personnel. Sensor should be able to sense the depletion or displacement of oxygen in the ma- chine room below 19.5% volume oxygen per ASHRAE 15, latest edition.

Design pressures

Design and test pressures for heat exchangers are listed below.

DESIGN AND TEST PRESSURES (23XRV)

	SHELL SIDE		STANDARD TUBE SIDE			OPTIONAL TUBE SIDE
PRESSURES	(Refrigerant)			(Liquid)			(Liquid)
	psig	kPa	psig		kPa	psig		kPa
Leak Test at Design Pressure*	185	1276	150		1034	300		2068
Hydrostatic	—	—	195		1344	390		2689
Proof Test*	204	1407	—		—	—		—

*Nitrogen/Helium.

HEAT EXCHANGER MATERIAL SPECIFICATIONS

ITEM	MATERIAL	SPECIFICATION
Shell	HR Steel	ASME SA516 GR 70
Tube Sheet	HR Steel	ASME SA516 GR 70
Condenser/Cooler Waterbox Cover	HR Steel	ASME SA516 GR 70, SA-36, or SA-285 GRC
Condenser/Cooler Waterbox Shell	HR Steel	ASME SA675 GR 60, SA-516 GR70, or SA-181 CL70,
		SA-36, SA-675 GR70, SAE AME 7496
Tubes	Finned Copper	ASME SB359
Discharge/Suction
Pipe	Steel	ASME SA106 GRB
Flanges	Steel	ASME SA105
LEGEND
ASME — American Society of Mechanical Engineers
HR — Hot Rolled

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