54
55
10-4. Self diagnosis and action
Check if Dip SW is set correctly. (Refer to Chapter 6-1.)
Error code
Title and display conditions
Possible Cause
Diagnosis and action
L
Circulation water temperature overheat
protection
<DHW/Heating/LP/FS/OS>
Error code displayed when THW1 detects a
temp. ≥ 80ºC for 10 consecutive seconds or
THW2 detects a temp. ≥ 80ºC for 10 consecutive
seconds.
DHW : Domestic hot water mode
Heating : Heating mode
LP
: Legionella prevention mode
FS
: Freeze stat
OS
: Operation stop
TH1A/B : Room temp. thermistor
TH2
: Liquid refrigerant temp. thermistor
THW1 : Flow water temp. thermistor
THW2 : Return water temp. thermistor
THW5 : Tank water temp. thermistor
THW6 :
Zone 1 flow water temperature thermistor
THW7 :
Zone 1 return water temperature thermistor
THW8 :
Zone 2 flow water temperature thermistor
THW9 :
Zone 2 return water temperature thermistor
THWB1 :
Boiler flow water temperature thermistor
THWB :
Boiler return water temperature thermistor
1
.
Insufficient system head
1
.
Refer to table in section 10-6. to determine
if system pump meets requirements.
If more head required either add an pump
of the same size or replace existing pump
with capacity model.
See 11. DISASSEMBLY PROCEDURE for
how to replace pump.
.
Reduced flow in primary water circuit
Due to 1 or more of the following;
Faulty pump, insufficient air purge,
blockedstrainer, leak in water circuit.
.
Check circulation pump (See 10-6. for how
to check).
Open purge valve to remove trapped air.
Check the strainer for blockages.
Check the primary water circuit for leaks.
Check that the flow amount is within the
recommended range.
.
Valve operation fault
.
Check valves on primary water circuit are
installed level.
4
.
2-way valve (field supply) actuator
fault
4
.
Electrically test to determine fault.
5.
3-way valve actuator fault
5
.
1) Electrically test to determine fault.
2) Operate 3-way valve manually using
the main remote controller. (Refer to
<Manual operation> in 9.).
3) Replace 3-way valve coil.
4)
Replace 3-way valve. (Refer to Procedure
6 in “11. DISASSEMBLY PROCEDURE.”
6.
Booster heater relay (BHC1, BHC,
BHCP) operating fault
6.
Electrically test the relays (BHC1, BHC,
BHCP) to determine fault.
See 10-6. for how to check.
7.
Power supply voltage increase
7.
Check the supply voltage.
8.
THW1 or THW5 has become de-
tached from its holder.
8.
Visually inspect location and reattach as
necessary.
9.
THW1 or THW fault
9.
Check resistance of thermistor against ta
-
ble in section 10-6.
Compare FTC4 detected temperature to
hand held detector.
10.
FTC4 board failure
10.
Replace board.
L4
Tank water temperature overheat protection
<DHW/Heating/LP/FS/OS>
Error code display when THW5 detects a
temp. ≥ 75ºC for 10 consecutive seconds.
1.
3-way valve actuator fault
1.
1) Electrically test to determine fault.
2) Operate 3-way valve manually using
the main remote controller. (Refer to
<Manual operation> in 9.).
3) Replace 3-way valve coil.
4) Replace 3-way valve. (Refer to Procedure
6 in “11. DISASSEMBLY PROCEDURE.”
.
Immersion heater relay (IHC) operat-
ing fault
.
Check immersion heater relay (IHC)
.
THW5 fault
.
Check resistance of thermistor against ta
-
ble in section 10-6.
Compare FTC4 detected temperature to
hand held detector.
4.
FTC4 board failure
4.
Replace board.
OCH531
Summary of Contents for ecodan EHPT20X- VM2HB
Page 89: ...89 OCH531 ...
