Mitsubishi Electric EHGT17D-YM9ED Service Manual page 16

Filling the System (Primary Circuit)
1. Check and charge expansion vessel.
2. Check all connections including factory fitted ones are tight.
3. Insulate pipework.
4. Thoroughly clean and flush, system of all debris.
5. Fill heat pump unit with potable water. Fill primary heating circuit with water and suitable anti-freeze and inhibitor as necessary. Always use a filling loop with
double check valve when filling the primary circuit to avoid back flow contamination of water supply.
When connecting metal pipes of different materials insulate the joints to prevent a corrosive reaction taking place which will damage the pipework.
6. Check for leakages. If leakage is found, retighten the nut onto the connections. Please make sure to prevent electrical part against water at draining.
7. Pressurise system to 1 bar.
8. Release all trapped air using air vents during and following heating period.
9. Top up with water as necessary. (If pressure is below 1 bar)
5
0
-5
-10
-15
-20
-25
0 10 20
Anti-freeze concentration [%]
Pre-commissioning exercises- potable/DHW circuit
Initial fill procedure:
Ensure all pipe joints and fittings are tight and secure.
Open the most distant DHW tap/outlet.
Slowly/gradually open the mains water supply to begin filling unit and DHW pipework.
Allow most distant tap to run free and release/purge residual air from installation.
Close tap/outlet to retain fully charged system.
Note: When an immersion heater is fitted, do NOT energise the heater until the DHW tank is full of water. Also do NOT energise any immersion heater if
any sterilisation chemicals remain in the DHW tank as this will cause premature failure of the heater.
Initial flush procedure:
Energise system to heat-up heat pump unit contents to a temperature of approx. 30 - 40°C.
Flush/drain the water contents to remove any residue/impurities resulting from the installation works. Use the heat pump unit drain cock to safely discharge the
warmed water to drain via a suitable hose.
On completion, close drain cock, re-fill system and resume system commissioning.
<Draining the heat pump unit and its primary heating circuit (local)>
WARNING: DRAINED WATER MAY BE VERY HOT
1. Before attempting to drain the heat pump unit isolate from the electrical supply to prevent the immersion and booster heaters burning out.
2. Isolate cold water feed to DHW tank.
3. Open a hot water tap to start draining without a vacuum.
4. Attach a hose to the DHW tank drain cocks (No. 23 on Figure 3.1 and Figure 7.2). The hose should be able to withstand heat as the draining water could be very
hot. The hose should drain to a place lower than the DHW tank bottom to encourage siphoning.
5. When the DHW tank is drained close drain cock and hot tap.
6. Attach hose to water circuit drain cocks (No. 7 on Figure 3.1). The hose should be able to withstand heat as the draining water could be very hot. The hose should
drain to a place lower than the booster heater drain cock to encourage siphoning. Open the pump valves and the strainer valves.
7. Water remains in the strainer still after the heat pump unit was drained.
Drain the strainer by removing the strainer cover.
OCH722A
30 40 50
<Figure 7.2>
23
Drain cocks
16