Mitsubishi Electric Ecodan EHSC series Installation Manual page 57

7
Service and Maintenance
No. Fault symptom
9 Water heating takes . Heat pump not working.
longer.
2. Booster heater cut-out tripped.
3. Booster heater breaker (ECB1) tripped.
4. The booster heater thermal cut-out has
tripped and cannot be reset using the manual
reset button.
5. Immersion heater cut-out has been triggered.
6. Immersion heater breaker (ECB2) tripped.
10 Temperature of DHW When DHW operation is not running, the DHW
tank water dropped. tank emits heat and the water temperature
decreases to a certain level. If water in the DHW
tank is reheated frequently because of a signifi-
cant drop in water temperature, check for the
following.
. Water leakage in the pipes that connect to
the DHW tank
2. Insulation material coming loose or off.
3. 3-way valve failure
 Hot or warm water Heat of hot water pipe is transferred to cold water
from cold tap. pipe.
2 Water leakage . Poorly sealed connections of water circuit
components
2. Water circuit components reaching the end of
life
3 Heating system does . Prohibit, schedule timer or holiday mode se-
not reach the set lected.
temperature.
2. Check settings and change as appropriate.
3. The temperature sensor is located in a room
that has a different temperature relative to
that of the rest of the house.
4. Heat pump not working.
5. Booster heater cut-out tripped.
6. Booster heater breaker (ECB1) tripped.
7. The booster heater thermal cut-out tripped
and can not be reset using the manual reset
button.
8. Incorrectly sized heat emitter.
9. 3-way valve failure
10. Battery problem (*wireless control only)
. If a mixing tank is installed, the flow rate be-
tween the mixing tank and the hydrobox is
less than that between the mixing tank and
the local system.
Possible cause
. Check heat pump – consult outdoor unit service manual.
2. Check booster heater thermostat and press reset button if safe.
3. Check the cause and reset if safe.
4. Check resistance across the thermal cut-out, if open then connection is broken
5. Check immersion heater thermostat and press reset button located on immersion
6. Check the cause and reset if safe.
.
2.
3.
Insulate/re-route pipework.
. Tighten connections as required.
2. Refer to PARTS CATALOG in the service manual for expected part lifetimes and
. Check settings and change as appropriate.
2. Check the battery power and replace if flat.
3. Relocate the temperature sensor to a more suitable room.
4. Check heat pump – consult outdoor unit service manual.
5. Check booster heater thermostat and press reset button if safe.
6. Check the cause of the trip and reset if safe.
7. Check resistance across the thermal cut-out, if open then the connection is broken and
8. Check the heat emitter surface area is adequate
9. Check plumbing/wiring to 3-way valve.
10. Check the battery power and replace it flat.
. Increase the flow rate between the mixing tank and the hydrobox decrease that
Explanation - Solution
Reset button is located on the side of booster heater, covered with white rubber
cap. See component parts diagram (section 3.) to find out its position.
and the booster heater will have to be replaced.
Contact your Mitsubishi Electric dealer.
heater boss, if safe. If the heater kept running with no water inside, this may have
resulted in failure, so replace it with a new one.
Take the following measures.
• Retighten the nuts holding the pipes onto the DHW tank.
• Replace seal materials.
• Replace the pipes.
Fix insulation.
Check plumbing/wiring to 3-way valve.
(i) Manually override 3-way valve using the main controller. (Refer to <Manual op-
eration> in section 5.7.) If the valve does not still function, go to (ii) below.
(ii) Replace 3-way valve coil. If the valve does not still function, go to (iii) below.
(iii) Replace 3-way valve. (Refer to the service manual.)
replace them as necessary.
Reset button is located on the side of booster heater, covered with white rubber
cap. (See component parts diagram section 3. for position.)
the booster heater will have to be replaced.
Contact your Mitsubishi Electric dealer.
Increase size if necessary.
between the mixing tank and the local system.
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