Carrier 30XW150-400 A30-4845, Cooler Head Recommended Bolt Torque Sequence, a30-4708, A30-4846

14	13	17
24			5
12			7
10			18
23			2
3			4
1			21
20			9
8			11
6			22
19	16	15	A30-4845

Fig. 49 — Cooler Head Recommended

Bolt Torque Sequence

INSPECTING/CLEANING HEAT EXCHANGERS — In- spect and clean cooler tubes at the end of the first operating season. Because these tubes have internal ridges, a rotary-type tube cleaning system is necessary to fully clean the tubes. Tube condition in the cooler will determine the scheduled frequency for cleaning, and will indicate whether water treatment is adequate in the chilled water/brine circuit. Inspect the entering and leaving water thermistor wells for signs of corrosion or scale. Replace the well if corroded or remove any scale if found.

CAUTION

3.If the contacts do not close with sufficient flow, then check the wiring connection to the MBB. If the input sig- nal is not closed, then the switch needs to be replaced.

a30-4708

WIRING

Fig. 50 — Chilled Water Flow Switch

Hard scale may require chemical treatment for its preven- tion or removal. Consult a water treatment specialist for proper treatment procedures.

WATER TREATMENT — Untreated or improperly treated water may result in corrosion, scaling, erosion or algae. The services of a qualified water treatment specialist should be obtained to develop and monitor a treatment program.

CAUTION

Water must be within design flow limits, clean and treated to ensure proper machine performance and reduce the potential of tubing damage due to corrosion, scaling, and algae. Carrier assumes no responsibility for cooler damage resulting from untreated or improperly treated water.

CHILLED WATER FLOW SWITCH — A factory-installed flow switch is installed in the entering water nozzle for all ma- chines. See Fig. 50 and 51. This is a thermal-dispersion flow switch. Figure 50 shows typical installation. If nuisance trips of the sensor are occurring, follow the steps below to correct:

When power is supplied to the device, a warm-up period is initiated. The warm-up period may take up to 30 seconds. When enough flow is detected, the switch contacts will close. The switch closure does not indicate minimum flow require- ments have been met for the machine.

LWT

EWT

CLWT

OUT

IN

OUT

IN

CWFS

1.Check to confirm that all strainers are clean, valves are open and pumps are running. For the case of variable frequency drive (VFD) controlled pumps, ensure the minimum speed setting has not been changed.

2.Measure the pressure drop across the cooler (evaporator). Use the cooler pressure drop curves in Fig. 27-37 to cal- culate the flow and compare this to system requirements.

CEWT

LEGEND

CEWT — Condenser Entering Water Thermistor CLWT — Condenser Leaving Water Thermistor CWFS — Chilled Water Flow Switch

EWT — Entering Water Thermistor LWT — Leaving Water Thermistor

A30-4846

Fig. 51 — Flow Switch (Typical)

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