Technical information
58
MAINTENANCE GUIDE
MAINTENANCE GUIDE: CLAS HE
5  ANNUAL MAINTENANCE 
Plate heat exchanger
Maintenance Interval: As necessary 
How: To measure specification of DHW performance. 
By-pass & Safety valve
Maintenance Interval: Annually 
How: Visual inspection / Clean as necessary 
Central heating filter
Maintenance Interval: Annually 
How: Visual inspection / Clean as necessary 
Flow switch operation
Maintenance Interval: Annually 
How: Visual inspection / Clean as necessary 
/ Check flow rate 
Expansion vessel
Maintenance Interval: Annually 
How: Check air pressure is at 1 bar (System drained) 
Ignition & detection electrodes
Maintenance Interval: Annually 
How: Visual inspection / Clean as necessary / Distance from the 
burner / Ionisation current more than 1 µA
Burner
Maintenance Interval: Annually 
How: Visual inspection / Clean as necessary 
Fan
Maintenance Interval: Annually 
How : Visual inspection / Clean as necessary 
Primary Heat exchanger
Maintenance Interval: Annually 
How : Visual inspection / Clean as necessary 
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