Bosch 25/32kW - Manual (Page 46)

FAULT FINDING PROBLEM CAUSE REMEDY
FAULTY BOILER
OPERATION:
Noisy operation Pump noise from air in pump or
worn pump Bleed air from pump or replace pump
Worn motor bearings Replace motor
Fan out of balance Replace fan
Boiling Faulty boiler thermostat Replace if necessary
Short circuit boiler thermostat Take out of circuit to check
Thermostat bulb not fully home in
pocket Ensure bulb is pushed fully home
No primary water circulation Check system / circulating pump
Short Cycling Burner rating incorrect Correct burner rating
Boiler thermostat differential
incorrect Replace boiler thermostat
External controls not operating
correctly Check and correct external controls
OIL SMELLS: Blocked flue, fumes on startup Check seals/gaskets
Oil soaked boiler, faulty burner
operation, numerous lockouts Rectify burner operation and lockouts
Odour in cabinet, oil leaks from
pipework, flexible hoses
connections Rectify oil leaks, replace components if
necessary
F
A
UL
T
F
IND
IN
G
& D
IA
G
R
A
M
S
FAULT FINDING
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR HEATSLAVE EXTERNAL 12/18-18/25-25/32
8 716 113 389b (09/07)
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