Crown Boiler PHNTM080 - Page 119

117
START
Is“ER**”presentin
upperleftcornerof
screen?
 Cons u ltfactory
Isdisplay
completely
dark?
 Looseordefectivedisplayharnesswiring
 Mismatcheddispl a y andboilercontrolsoftware
 UnauthorizedModbusapplication–interrupt
powertotheboiler.Ifnormaldisplayre‐
appears,restorefactorysettings.
 Temporaryerrorcausedbynoise–interrupt
powertotheboilerandseeiferrorclears.
 Defectivedisplay.
 Looseordefective
connectionbetweenthe
displayandterminalJ3on
boilercontrol.
 DefectiveDis play
Isboilercontrol’s
greenpowerlight
on?
Is120VACpresent
across120VLine
connectionsL&Non
HighVoltagePCB?
 Openfuseorbreakeratmain
panel.
 Looseconnectioninwiring
betweenmainpanelandboiler
Is24VACpresent
betweenJ8‐1andJ8‐2
(BlueandYellow)
terminalsonboiler
control?
 Defectiveboiler
control(R7910B)
24VACpresentacross
transformersecondary(brown
andpinkwiresatpl ugL3)?
 Blown24VfuseonlowvoltagePCB–
lookforshortcircuitin24Vwiring
beforereplacing.Replacewith
5x20mm1.6Aslowblowtypefuse.
 LooseplugP8(locatedonbacksideof
lowvoltagePCB)
 LooseplugL 3
120VACpresent
acrossblack
andwhitewires
atL2?
 LooseplugL 2
 LooseplugP3(locatedonback
sideofHighVoltagePCB)
 Defectivetransformer
–lookforshortcircuit
in24Vwiring.Confirm
installed24Vfuseis
1.6A
Y
N
Y
Y
Y
Y
Y
Y
N
N
N
N
N
N
Isboilerfan
runningathigh
speed?
N
Y
FIGURE 14.3: TROUBLESHOOTING BLANK OR UNREADABLE SCREEN