Instruction manual

K4, K6, K9 series chillers – Installation and Operation manual
Issue 10.33
Page 9
phase components (fans, controller and solenoid), is located to the rear of the electrical
box inside the unit. See Figure 1, page 11.
Setting the maximum permissible fluid pressure
If your chiller is fitted with a rotary vane pump, it will be fitted with a pressure control
valve as standard. This type of pump is ideal for small capacity chillers as it is very
efficient and capable of very high pressures with little or no loss of fluid flow at higher
pressures. ATC fit a pressure control valve as standard, to protect your application from
damaging over pressure. Pump types affected by the pressure control system are P5,
P8, P10 and P17. The valve simultaneously limits the maximum permissible system
pressure and the operation flow and pressure characteristics. It is important to understand
that the pressure displayed during normal operation is lower than the peak pressure in a
deadhead situation. In the event of blockage of a return line from the application, the
pressure may exceed 10 bar (150 psi). The pressure control valve is factory set to 50 psi
(1.5 bar). If your application is incapable of sustaining this pressure, the following
adjustment must be made:
1. Connect a short length of flexible hose between the inlet and outlet of the chiller.
2. Following the ‘filling procedure’ (see earlier this section) carefully fill the tank with
fluid and switch on.
3. With the chiller running, fold the flexible tubing back on itself, and secure with a
cable tie to block the fluid outlet.
4. Read the pressure displayed on the front panel.
5. Adjust the pressure using the pressure control valve (‘A’ in Figure 2, page 11) until
your known maximum system pressure shows on the front panel. NOTE - in optional
low temperature chillers, this is metallic and covered in insulating material
The maximum system pressure attainable has now been adjusted. Please be aware that the
actual running pressure will be lower than this value. If the maximum system pressure is
close to the actual pressure achieved during normal operation, only a proportion of the
pump’s output will be supplied to your application.