Mitsubishi EHST20C-VM2C - Page 66

66
Error code Title and display conditions Possible Cause Diagnosis and action
L9 Lowprimarycircuit(Zone2side)owrate
detectedbyowswitch
Note: “3” is displayed in “Request code: 569” in
“Runninginformation”.
1. Insufcientsystemhead 1. If more head required either add a pump of
thesamesizeorreplaceexistingpump.
2. Reducedowinprimarywatercircuit
Dueto1ormoreofthefollowing;
Faultypump,insufcientairpurge,
blockedstrainer,leakinwatercircuit
2. Checkcirculationpump(See"10-6.
CheckingComponentParts'Function"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owamountiswithinthe
recommendedrange.
3. Terminalwirehasbecomedetached
orloosewiring.
3. Visually check the IN7 terminal and
reattach if necessary.
4. Flowswitchfault 4. Electrically test to determine fault.
5. IncorrectsettingoftheSW3-3 5. ChecktheSW3-3setting.
6. FTC board failure 6. Replace board.
LC Boilercirculationwatertemperatureoverheat
protection
<DHW/Heating/LP/FS/OS>
ErrorcodedisplayedwhenTHWB1detectsa
temp.≥80ºCfor10consecutivesecondsor
THWB2detectsatemp.≥80ºCfor10consecu-
tive seconds
1. The set temperature for Boiler is too
high.
1.
Check if the set temperature for Boiler for
heatingexceedstherestriction.(Seethe
manualforthethermistors"PAC-TH011HT-E")
2. Flowrateoftheheatingcircuitfromthe
boiler may be reduced.
2. Check for
•waterleakage
•strainerblockage
•watercirculationpumpfunction.
LD Boiler temperature thermistor (THWB1, THWB2)
failure
Refer to error codes (P1/P2/L5/LD).
LE Boiler operation error
<Heating>
BoilerisrunningandTHW6detectsa
temperature<30ºCforconsecutive60minutes.
1. THW6 has become detached from its
holder.
1. Visually inspect location and reattach as
necessary.
2. IncorrectwiringbetweenFTC(OUT10)
and the boiler.
2. See the manual of the thermistors
"PAC-TH011HT-E".
3. Boiler fuel has run out or the system is
OFF.
3. Check the status of the boiler.
4. Boiler failure 4. Check the status of the boiler.
5. FTC board failure 5. Replace board.
LF Flowsensorfailure Disconnectionorlooseconnectionofow
sensor
Checkowsensorcablefordamageorloosecon-
nections.
LH Boilercirculationwaterfreezeprotection Flowrateoftheheatingcircuitfromtheboil-
er may be reduced.
Check for
•waterleakage
•strainerblockage
•watercirculationpumpfunction.
LJ
DHWoperationerror(typeofexternalplateHEX)
1.DHWtankwatertemp.thermistor
(THW5) has become detached from its
holder.
2.Flowrateofthesanitarycircuitmaybe
reduced.
1. CheckfordisconnectionofDHWtankwater
temp. thermistor (THW5).
2. Checkforwatercirculationpumpfunction.
LL SettingerrorsofDIPswitchesonFTCcontrol
board
IncorrectsettingofDIPswitches.
1. Boiler operation 1. For boiler operation, check that DIP SW1-1
is set to ON (With Boiler) and DIP SW2-6 is
settoON(WithMixingTank).
2. 2-zonetemperaturecontrol 2. For2-zonetemperaturecontrol,checkDIP
SW2-7issettoON(2-zone)andDIP
SW2-6issettoON(WithMixingTank).
P1 Indoor unit temperature thermistor (TH1) failure Refer to error codes (P1/P2/L5/LD).
P2 Indoor unit temperature thermistor (TH2) failure Refer to error codes (P1/P2/L5/LD).
P6
Anti-freezeprotectionofplateheatexchanger
<Cooling>
TheerrorcodedisplayedwhenRef.liquidtemp.
(TH2)staysat−5
ºCorlowerfor10secondsafter
compressor operates for 6 minutes.
<Cooling>
1. Reducedwaterow 1., 2. Checkwaterpiping.
•Cloggedlter
•Leakageofwater
2. Lowtemperature
•Lowload
•Inletwateristoocold.
3. Defectivewaterpump 3. Checkwaterpump.
4. Defective outdoor fan control. 4. Check outdoor fan motor.
5. Overchargeofrefrigerant
5., 6. Checkoperatingconditionofrefrigerantcircuit.
6. Defectiverefrigerantcircuit(clogs)
7. Malfunctionoflinearexpansionvalve 7. Checklinearexpansionvalve.
<Defrosting>
THW2detectsatemperature≤15ºCandTH2
detectsatemperature≤−16ºCforconsecutive10
seconds.
<Defrosting>
1. Reducedwaterow
1., 2. Checkwaterpiping.
•Cloggedlter
•Leakageofwater
2. Lowtemperature
•Lowload
•Inletwateriscold.
3. Defectivewaterpump 3. Checkwaterpump.
4. Leakageorshortageofrefrigerant 4. Correcttoproperamountofrefrigerant.
5. Malfunctionoflinearexpansionvalve 5. Checklinearexpansionvalve.
OCH570C