Step by step installation of an air source heat pump

In September, Worcester will launch a Greensource air-to-air heat pump series to complement its Greenstore ground source heat pump series. Martyn Bridges, director of technical support and marketing for Worcester, Bosch Group, talks through the steps of installing a Greensource air-to-air heat pump.

To begin, it is important to find a suitable site to store the Greensource outdoor inverter unit. If choosing a floor siting situation, the system requires a stable base and should be sheltered from rain water and strong winds; not be exposed to muddy water (along a road for example) or in a position where the unit can be tampered with. It is also worth keeping in mind that the unit’s location should be far enough away that outgoing air and operating noise won’t annoy the homeowner or the neighbours.

A good tip to ensure a successful installation is to complete a log throughout the commissioning process; this will help remind you of all the steps that need to be completed.

Once happy with the chosen site, position the outdoor unit according to the installation instructions. The Greensource air source heat pump can be mounted onto a wall or directly onto the floor. Allow a 200mm clearance around the appliance to provide as much installation space as possible for efficient air-conditioning.

Next, install the external wall bracket. Place the mounting plate horizontally on the wall allowing 50mm clearance on both sides and mark the location for the wall plugs and the tube hole. Then drill the 6.5mm diameter and 32mm depth holes and fit the wall plugs.

Secure the mounting plate in seven places and check it is firm. Drill a 70mm diameter hole, to hold the electrical cables and refrigerant pipework, with a 5mm downward slant to the outside. Set the sleeve and the caps.

Connect the electrical cable to the indoor unit. Open the panel by about 70° and remove, and retain the screw from the indoor unit. Connect the electrical cable ensuring the markings on the indoor unit’s terminal board match those of the outdoor unit. Be careful not to confuse the terminal connections as wrong cabling may damage the internal control circuit. Fix the cable with the cord holder and replace the retained screw.

Mount the indoor unit to the wall. Pass the auxiliary pipe and the drain hose through the piping hole and hook the unit onto the mounting plate. Push the unit and apply the bottom hooking points to the mounting plate’s support. Check it is fixed in place by gently pulling the bottom of the unit.

Connect the refrigerant and drain hose pipes. Flare the end of the refrigerant pipe in order to connect. Lay the drain hose vertically to ensure a smooth drainflow with no traps. Tighten the pipes by hand for the first 3-4 turns and then use a wrench or torque spanner. Wind coating tape around the refrigerant pipes together with the drain hose and the electrical cable.

Insulate the refrigerant pipes and drain hose. The thermal insulation should cover both the gas and liquid pipes, using class O insulation 6mm or thicker.

Connect the refrigerant pipes and the electrical cable to the outdoor unit. Prepare the end of the electrical cable and remove the control box cover. Remove the cable holder and connect the cable ensuring the terminal connections are as specified. Take care to dress the cable so that the control box cover, the cord holder and cable holder are not loose to avoid overheating, fire or electric shock. Fix the electrical cable sheath with the cable holder and the screw. Place the control box cover back in the reverse order.

Prepare a dedicated power supply circuit. The appliance should be installed in accordance with national wiring regulations. Provide an earth leakage circuit breaker and fit a disconnection switch, having a contact separation of at least 3mm in all poles to the electricity power line.

Complete the installation by doing a test run. Open the panel to view the control section, then start the operation with the remote control and press ‘AUX’ for five seconds or more. You should hear a beep sound and the ‘operation’ lamp will start to flash, indicating that the system is in the cooling test run mode. To test the heating mode simply select ‘heating mode’ on the remote control.

One of the best ways to avoid call-back from a customer after installation is to talk the homeowner through the air source heat pump to cover any questions they may have on the product before you leave the property. Make sure you leave all product literature with the customer.

At Worcester we provide thorough training and a detailed commissioning check-list which ensures that everything is checked during the commissioning process. All Worcester approved installers give every customer a detailed handover explaining how the air source heat pump works. This ensures the customer is happy with their air source heat pump and understands fully how to operate it.

Spending time with the customer will most definitely save you time in the long run, as there’s a far less chance of a call-back.

Please note that it is a requirement that the installer/commissioning engineer of an air to air heat pump holds the necessary refrigerant handling qualifications.

For more information about Worcester’s air source heat pumps and training facilities contact 08705 266 241 or visit www.worcester-bosch.co.uk.