BISN0047.0
26/06/2007 Page 6
Fault Finding.
Problem
Possible Cause
Solution
Appliance does not light
No gas supply
Blocked pilot
Connect to supply
Replace pilot injector
Pilot lights but no main burner
Split/Distorted diaphragm
Replace
Smell of gas
Luminous flame
Loose gas connection
Clean burner
Locate leak with soap solution
Yellow flame
Burner venturi blocked
Clean with venturi brush
Water leak on top of water valve lid
Damaged O ring
Excessive pressure
Frost damage
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
Low burner flame, water does not
heat up.
Low inlet gas pressure
Low burner pressure
Check supply regulator and pipe
size
Check appliance regulator
Check thermostat bellows
Check thermostat insert
Low water temperature
Water flow rate set too high
Low gas pressure
Thermostat faulty/out of
adjustment
Set flow rate
Check pressure
Replace/Adjust thermostat
Low water flow
Low water pressure
Blocked water valve
Blocked heat exchanger
Blocked shower rose or tap
aerator
Check and adjust
Clean filter
Descale
Clean
Shower goes hot & cold
Low flow water saver shower rose Replace with less restrictive rose.
Check operation at other tap
Operates only at high water flow
Relief valve spring corroded
Installed incorrectly, cold supply to
hot outlet
Replace valve
Correct installation
Cuts off when operating
Thermostat faulty/out of
adjustment
Wrong thermostat insert
Replace/Adjust thermostat
Fit correct part
Operates only with slow light valve
loose
Faulty diaphragm
Blocked passage between slow
light & venturi
Faulty slow light valve
Replace
Clean
Clean/Replace
