Technical data

5.2 Heat Pump Operation

Prior to use: -

i. Turn off the power supply at the local isolator

ii. Unscrew the 4 x 5mm hex socket screws on either side of the front panel (2 each side). Remove the

front panel.

iii. Check that the ground pressure gauge reads at least 0.3 bar. If the pressure is lower than this, open

the mains cold water supply valve (fitted outside the case) fully until the gauge reads at least 1.8 bar,

at which point a “click” will be heard. Close the mains cold water supply valve fully.

iv. Check that the heating distribution system pressure gauge reads at least 0.3 bar. If the pressure is

lower than this, find the mains cold water supply valve and pressurize the system until the gauge

reads at least 1.8 bar, at which point a “click” will be heard. Close the mains cold water supply valve

fully. Reassemble the front panel taking care to ensure that the 4 x hex screws are located correctly.

A purge pump can achieve pressures of 5 bar and it is acceptable that the ground arrays are left at

this pressure.

v. Turn on the power supply at the local isolator and program the external timeclock / thermostat.

5.3 Turning the Heat Pump on for the first time.

i. Make sure the impellors in both the ground and heating distribution water pumps are free to turn

by removing the stainless steel screws (if fitted) in the centre of each water pump and inserting a

flat-bladed screwdriver to spin the impellor. Do not try to spin the impellor with the power on.

ii. Turn the 4 Amp MCB on to enable the controls and water pumps to operate. Operating this MCB

should result in a sudden sharp change in pressure on the underfloor pressure gauge and indicates

that the pump is operational. Shortly after operating this MCB, the compressor contactor should

engage. This will result in a sudden sharp change of pressure indicated on the ground array pressure

gauge and this indicates that the ground array water pump is operational. DO NOT operate the com-

pressor MCB until Vent-Axia has been contacted and flow has been confirmed around the system.

Failure to do this will cause the unit to freeze and may invalidate the warranty.

iii. The controller display will read the temperature of the water returning from the heating system. If

the error Tp is displayed, then the heat pump will not run until both heating distribution and ground

circuits are above 1.8 bar pressure.

iv. The commissioning of the heat pump will be carried out remotely (via phone) by a Vent-Axia

commissioning engineer and a heat pump commissioning certificate and checklist issued on

completion. Please contact Vent-Axia to book a commissioning call.

v. After commissioning and connection to the heating control system (with the power isolated) remove

the enable link between terminals 1 and 2.

vi. If DHW is enabled (with the power isolated) remove the enable link between the DHW terminals. (5

& 6)

Fig 29 Spinning the pump