Viessmann VITOPEND 100-W Installation And Service Instructions Manual page 33

Control unit diagnostics
8 A U tr
ON fla-
shes
ON fla- fla-
shes shes
ON fla- fla-
shes shes
ON ON
Extended fault displays
To display detailed fault causes, initially turn rotary selector "rt" fully anti-
clockwise and then fully clockwise.
8 A U tr
ON fla-
shes
ON fla-
shes
ON fla-
shes
ON fla-
shes
ON fla-
shes
(cont.)
tw LEDs Function
flash
fla- alternat- Outlet temperature sensor (gas
shes ing fired combi boiler) or cylinder
temperature sensor (gas fired
central heating boiler) lead bro-
ken
simulta- Flue gas monitoring sensor
neously shorted out
alternat- Flue gas monitoring sensor lead
ing broken
Burner control unit fault
To reset the burner switch the
control unit ON/OFF switch first
OFF and then ON again.
tw LED Function
flashes
1 time/ The temperature limiter/boil-dry
10 s protection device has responded.
To reset the burner, turn rotary se-
lector "rt" briefly fully clockwise
"E" and then back to the required
heating water temperature.
2 time/ No flame signal after safety time
10 s
3 time/ The air pressure switch does not
10 s respond
4 times/ Flame signal present after the
10 s burner run-on time
5 times/ Flame signal present before burn-
10 s er start
Troubleshooting
33