Fault Finding - Bosch 10P Installation & Operating Instructions Manual

Problem
Appliance does not light
Pilot lights but no main burner
Smell of gas
Yellow flame
Water leak on top of water valve lid
Low burner flame, water does not
heat up.
Low water temperature
Low water flow
Shower goes hot & cold
Operates only at high water flow
Cuts off when operating
Operates only with slow light valve
loose
BISN0029

Fault Finding.

Possible Cause
No gas supply
Blocked pilot
Split/Distorted diaphragm
Luminous flame
Loose gas connection
Burner venturi blocked
Damaged O ring
Excessive pressure
Frost damage
Low inlet gas pressure
Low burner pressure
Water flow rate set too high
Low gas pressure
Thermostat faulty/out of
adjustment
Low water pressure
Blocked water valve
Blocked heat exchanger
Blocked shower rose or tap
aerator
Low flow water saver shower rose
Relief valve spring corroded
Installed incorrectly, cold supply to
hot outlet
Thermostat faulty/out of
adjustment
Wrong thermostat insert
Faulty diaphragm
Blocked passage between slow
light & venturi
Faulty slow light valve
Solution
Connect to supply
Replace pilot injector
Replace
Clean burner
Locate leak with soap solution
Clean with venturi brush
Replace O ring, grease with
#
Unisilkon L641
8709918413
Check water isolating valve
(Must be gate valve or similar)
Drain appliance or fit Exogel
#
expansion valve
H707060151
Check supply regulator and pipe
size
Check appliance regulator
Check thermostat bellows
Check thermostat insert
Set flow rate
Check pressure
Replace/Adjust thermostat
Check and adjust
Clean filter
Descale
Clean
Replace with less restrictive rose.
Check operation at other tap
Replace valve
Correct installation
Replace/Adjust thermostat
Fit correct part
Replace
Clean
Clean/Replace
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25/10/2011
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