Installation manual

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3.2 Plumbing - Installation
• The system must be filled and flushed with clean fresh water to ensure the removal of all the air from the
installation. Air bleed points must be installed at the highest point in the system; in particular, the installer must
remember to install an air bleed on the heat pump pipe if it is a local high point since there is no air bleed point
on the heat pump itself. Dimplex recommend the use of a power flush and purge cart to facilitate this process.
• Flow and return isolation valves and piping must be fitted to each of the heat pump water connections on the
back of the heat pump, as shown in figure 4.
• The isolation valve on the return is also fitted with a non-return valve and a strainer (included in the Dimplex heat
pump hydraulics pack). This means that in order to clean the strainer, the system does not have to be drained.
Instead, it is possible just to close the isolation valves on the return and remove the strainer. This way, the only
water that will be lost from the system is that between the non-return valve and strainer.
• The strainer must be fitted in order to prevent contamination of the condenser heat exchanger. If an alternative
strainer is used, it must be at least 7 microns in size.
• System should be pressurised and the system pressure must be checked once valves are re-opened.
• Direct condensate drain pipe to soak away or drain.
• All piping must be properly insulated and external length kept to a minimum.
Adjusting the By-Pass Valve
The bypass valve is used to maintain a minimum flow rate and prevents faulty operation of the heat pump, as well as
allowing it to run efficiently. The bypass valve must be adjusted correctly after commissioning the heat pump.
Please ensure that the following steps are taken when adjusting the bypass valve;
1. Ensure that the bypass valve is open fully and begin running the heat pump.
2. Close all of the heating circuits that may be closed during the operation of the heating system so that the least
favourable flow rate can be achieved. This should cause all of the flow to go through the bypass valve. To check
that all of the water flow is going through the bypass valve, feel the pipe after the valve to check its temperature
(it should be getting heat from the heat pump).
3. Slowly close the valve until the water is no longer flowing through it, then turn the valve back slightly (approx. 0.5
to 1 turn) to allow some flow and prevent the heat pump from tripping.
4. Open the zone valves while the heat pump is still running, and again check the flow through the bypass valve by
feeling the pipe after the valve and checking its temperature (it should not be as hot as flow temperature). The
bypass setting should allow hot water to flow through the bypass valve when some of the heating circuits are
closed.
3.3 Electrical Information
The heat pump system consists of the heat pump, wiring centre and user interface. If a Dimplex A-Class cylinder is also
used, the wiring centre is built into the cylinder.
The user interface acts as a thermostat and is sufficient if one heating zone is present. Optional, additional temperature
probes or room thermostats are required for additional heating zones.
Figures 5 & 6 show the different possible wiring configurations for systems with and without a Dimplex A-Class cylinder.