heat-timer EPU-D User Manual

Troubleshooting41
059840‐00Rev.AHeat‐TimerCorp.
Troubleshooting
Symptom PossibleCause RecommendedAction(s)
Nodisplayor
distorteddisplay.
NopowertotheEPU‐D
ControlModule,incorrect
ordefectivewiring.
VerifytheEPU‐DControlModuleisreceivingpower,allpower
wiringisingoodconditionandconnected.
TheEPU‐DControlModulerequires120Vacpowertoterminal
1and2,andearthgroundwiringtoterminal3.
TurnpowertotheEPU‐DControlModuleoffthenbackon.
See“PowerInputWiring”onpage 16.
Displayshows
sensor“Open”.
Sensordisconnected. VerifythesensorisproperlyconnectedtotheEPU‐DControl
Module.
Defectivesensor,wires,or
EPU‐DControlModule.
Disconnectthesensorinputwiresfromthecontrolandusean
Ohmmetertomeasuretheresistancebetweenthesensor
wires.RefertoTable 2onpage 43.
• Ifthereadingsareoutofrange,thesensororthewiring
maybedefective.Replacethesensor/wiring.
Connectthesensorwirestothecontrolanddisconnectthe
wiresfromthesensorterminals.Shortthewirestogether.
• Ifthedisplaystillreads“Open”,thecontrolisdefective.
ReplacetheEPU‐DControlModule.
Displayshows
sensor“Short”.
Defectivesensor,wires,or
EPU‐DControlModule.
Removethewiresfromthesensorterminals.Thedisplay
shouldread“Open”.
• Ifthedisplaystillreads“Short”,thecontrolisdefective.
ReplacetheEPU‐DControlModule.
• Ifthedisplayreads“Open”,thesensormaybedefective.
Replacethesensor/wiring.
Displayshowsan
incorrect
temperature.
DefectiveEPU‐DControl
Module,sensor,orwiring.
Removethewiresfromthesensorterminals.Thedisplay
shouldread“Open”.
• Ifthedisplaydoesnotread“Open”,thecontrolis
defective.ReplacetheEPU‐DControlModule.
UseanOhmmetertomeasuretheresistancebetweenthe
sensorwires.RefertoTable 2onpage 43.
• Ifthereadingsareoutofrange,thesensororthewiring
maybedefective.Replacethesensor/wiring.

heat-timer EPU-D Specifications

General

Brand	heat-timer
Model	EPU-D
Category	Control Panel
Language	English