Mitsubishi Electric EHWT17D-MHEDW, Справочник данных

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No. Fault symptom Possible cause Explanation - Solution
13 Heating system does
not reach the target
temperature.
1. Prohibit, schedule timer or holiday mode se-
lected or demand control input (IN4) or smart
grid ready (switch-off command).
1. Check settings and change as appropriate.
2. Check settings and change as appropriate. 2. Check the battery power and replace if flat.
3. The temperature sensor is located in a room
that has a different temperature relative to
that of the rest of the house.
3. Relocate the temperature sensor to a more suitable room.
4. Heat pump not working. 4. Check heat pump.
5. Booster heater cut-out tripped. 5. Check booster heater thermostat and press reset button if safe.
Reset button is located on the side of booster heater, covered with white rub-
ber cap. (See "7.5.1 Component parts" for position.)
6. Booster heater breaker (ECB1) tripped. 6. Check the cause of the trip and reset if safe.
7. The booster heater thermal cut-out tripped
and cannot be reset using the manual reset
button.
7. Check resistance across the thermal cut-out, if open then the connection is bro-
ken and the booster heater will have to be replaced.
Contact your Mitsubishi Electric dealer.
8. Incorrectly sized heat emitter. 8. Check the heat emitter surface area is adequate
Increase size if necessary.
9. 3-way valve failure 9. Check plumbing/wiring to 3-way valve.
(i) Manually override 3-way valve using the main remote controller. (Refer to
<Manual operation> in "7.7 System setup".) If the 3-way valve does not
function, go to (ii) below.
(ii) Replace 3-way valve motor. 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 Service manual.)
10. Battery problem (wireless control only) 10. Check the battery power and replace if flat.
11. If a mixing tank is installed, the flow rate
between the mixing tank and the unit is less
than that between the mixing tank and the
local system.
11. Increase the flow rate between the mixing tank and the unit decrease that
between the mixing tank and the local system.
14 In 2-zone tempera-
ture control, only
Zone2 does not
reach the target
temperature.
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 installation manual, "7.4.3 Wiring for 2-zone temperature control".
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 unit 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 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 "7.7 System setup".) 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 Service manual.)
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.
Recharge to 1 bar if necessary.
If bladder perished replace expansion vessel with a new one.
18 Water discharges
from pressure relief
valve.
(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 could bite
foreign objects and the valve seat may be
damaged.
2. Turn the handle on the pressure relief valve several turns. If leakage persists,
replace the pressure relief valve with a new one.
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
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.
B-257
Water to Water Heat Pump (WTW)
7
Cylinder
unit/
Hydrobox/GSHP/WTW
Cylinder
unit/
Hydrobox/GSHP/WTW