GCH15010
45
No.
Fault symptom
Possible cause
Explanation - Solution
15 After DHW operation
room temperature
rises slightly.
At the end of the DHW mode operation the 3-way
valve diverts hot water away from the DHW circuit
into space heating circuit.
This is done to prevent the cylinder unit compo-
nents from overheating.
The amount of hot water directed into the space
heating circuit varies according to the type of the
system and of the pipe run between the plate heat
exchanger and the cylinder unit.
Normal operation no action necessary.
16 The room tempera-
ture rises during DHW
operation.
3-way valve failure
Check the 3-way valve.
(i) Manually override 3-way valve using the main remote controller. (Refer to
<Manual operation> in 9-4). If the 3-way valve does not function, go to (ii)
below.
(ii) Replace 3-way valve coil. If the 3-way valve coil is replaced but the 3-way
valve does not function go to (iii) below.
(iii) Replace 3-way valve. (Refer to 11. DISASSEMBLY PROCEDURE.)
17 Water discharges
from pressure relief
valve.
(Primary circuit)
1. If continual – pressure relief valve could bite
foreign objects and the valve seat may be
damaged.
1. Turn the handle on the pressure relief valve several turns. If leakage persists,
replace the pressure relief valve with a new one.
2. If intermittent – expansion vessel charge may
have reduced/bladder perished.
2. Check pressure in expansion vessel.
3. Heating circuit is closed and pump is running.
2. Open the heating circuit.
Recharge to 1 bar if necessary.
If bladder perished replace expansion vessel with a new one.
18 Noisy water circulation
pump
Air in water circulation pump.
Use manual and automatic air vents to remove air from system.
Top up water if necessary to achieve 1 bar on primary circuit.
Use manual and automatic air vents to remove air from system.
Top up water if necessary to achieve 1 bar on primary circuit.
19 Noise during hot
water draw off
typically worse in the
1. Loose airing cupboard pipework.
1.
Install extra pipe fastening clips.
2.
Air in water circulation pump A.
2.
20 Mechanical noise
heard coming from
the cylinder unit.
1. Heaters switching on/off.
Normal operation no action necessary.
2.
3-way valve changing position between
DHW and heating mode.
21 Water circulation
pump runs for a short
time unexpectedly.
Water circulation pump jam prevention mechanism
(routine) to inhibit the build-up of scale.
Normal operation no action necessary.
22 Milky/Cloudy water
(Sanitary circuit)
Oxygenated water
Water from any pressurised system will release oxygen bubbles when water is
running. The bubbles will settle out.
23 Heating mode has
been on standby for
a long time (does
not start operation
smoothly.)
The time of “Delay” set in “Economy settings
for pump” is too short. (Go to “Service menu”
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pump”).
Increase the time of “Delay” in “Economy settings for pump” .
24 The cylinder unit
that was running in
the heating mode
before power failure
is running in the
DHW mode after
power recovery.
The cylinder unit is designed to run in an operation
mode with a higher priority (i.e. DHW mode in this
case) at power recovery.
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After the DHW max. operation time has elapsed or the DHW supply max.tem-
perature has been reached, the DHW mode switches to the other mode
(e.g. Heating mode).
morning.