51
No.
Fault symptom
Possible cause
Explanation - Solution
14
In 2-zone tempera-
ture control, only
Zone2 does not
reach the set tem-
perature.
1.
When Zone1 and Zone2 are both in heating
mode, the hot water temperature in Zone2
does not exceed that in Zone1.
1. Normal action
No action necessary
2.
Faulty wiring of motorized mixing valve
2.
Refer to "5.3 Wiring for 2-zone temperature control" in installation manual.
3.
Faulty installation of motorized mixing valve
3. Check for correct installation. (Refer to the manual included with each mo
-
torized mixing valve.)
4.
Incorrect setting of Running time
4. Check for correct setting of Running time.
5.
Motorized mixing valve failure
5. Inspect the mixing valve. (Refer to the manual included with each motorized
mixing valve.)
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 hydrobox components
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 hydrobox.
•
Normal operation
•
No action necessary
16
The room tempera-
ture rises during DHW
operation.
3-way valve failure
Check the 3-way valve.
17 Water discharges
from pressure relief
valve.
(Primary circuit)
1. If continual – pressure relief valve may be
damaged.
1.
Turn the handle on the pressure relief valve to check for foreign objects in it.
If the problem is not still solved, 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.
Recharge to 1 bar if necessary.
If bladder perished replace expansion vessel with a new one.
18 Water discharges
from pressure relief
valve (field supplied
item).
(Sanitary circuit)
1.
If continual – field supplied pressure reducing
valve not working.
1.
Check function of pressure reducing valve and replace if necessary.
2. If continual – pressure relief valve seat may
be damaged.
2.
Turn the handle on the pressure relief valve to check for foreign objects
inside. If the problem is not still solved, replace the pressure relief valve.
3. If intermittent – expansion vessel charge may
have reduced/bladder perished.
3. Check gas-side pressure in expansion vessel.
Recharge to correct precharge pressure if necessary.
If bladder perished replace expansion vessel with a new one with appropriate
pre-charge.
4. DHW tank may have subjected to backflow.
4. Check the pressure in DHW tank. If pressure in DHW tank is similar to that in
the incoming mains, cold water supply that merges with incoming mains wa
-
ter supply could flow back to DHW tank. Investigate source of back-feed and
rectify error in pipework/fitting configuration. Adjust pressure in cold supply.
19
Noisy water circula
-
tion 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.
20 Noise during hot
water draw off
typically worse in the
morning.
1.
Loose airing cupboard pipework
1.
Install extra pipe fastening clips.
2.
Heaters switching ON/OFF
2. Normal operation
No action necessary
21 Mechanical noise
heard coming from
the hydrobox.
1.
Heaters switching ON/OFF
•
Normal operation
•
No action necessary
2.
3-way valve changing position between DHW and
heating mode
22
Water circulation
pump runs for a
short time unexpect-
edly .
Water circulation pump jam prevention mechanism
(routine) to inhibit the build-up of scale
•
Normal operation
•
No action necessary
23 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.
24 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”
→ “Auxiliary settings” → “Economy settings for
pump”).
Increase the time of “Delay” in “Economy settings for pump”.
25
The hydrobox that
was running in the
heating mode before
power failure is
running in the DHW
mode after power
recovery.
The hydrobox is designed to run in an operation
mode with a higher priority (i.e. DHW mode in this
case) at power recovery.
• Normal operation
• After the DHW max. operation time has elapsed or the DHW max. temperature
has been reached, the DHW mode switches to the other mode (ex. Heating
mode).
OCH590B
