If your boiler is under warranty and you are experiencing difficulties, please contact the distributor from where you purchased it, or Calomax directly - Tel: 0113 249 6681 / Fax: 0113 235 0358 / e-mail: service@calomax.co.uk

The pages below outline some of the more common faults that may arise from time to time and are designed to supplement your own practical experience of our products and the information found in our operation and maintenance manuals

All our boilers are made in the UK, and serviced regularly, should give many years faithful service. The biggest problem, in common with all hot water equipment, is the formation of lime-scale and general water quality. Whilst all our products (except CB & CB/S) incorporate an integral scale inhibitor, we strongly recommend the use of an additional in-line water filter to ease taste, odour and lime-scale problems where appropriate. For further information please visit our accessories page

For servicing and spare parts we recommend that you contact one of our regional service partners and/or spare parts stockists

Repairs and servicing should only be attempted by experienced and competent personnel. If you decide to service or repair your Calomax boiler yourself, please read the appropriate operation and maintenance manual to familiarise yourself with the machine before starting. Manuals can be freely downloaded from our website.

FAULT SCENARIO 1 - BOILER OVER BOILING (ALL BOILERS EXCEPT CB & CB/S)

NOTE: IF THERE ARE NO LIGHTS LIT ON THE FRONT OF BOILER BUT THE SUPPLY TO THE UNIT IS OK, THIS INDICATES THAT THE OVERHEAT STAT HAS TRIPPED. RESET STAT. CHECK FOR CAUSE OF TRIP.

• CHECK FOR SCALE BUILD UP ON THERMISTOR.

• ELEMENT FAILURE TO EARTH. BECAUSE THE ELEMENT IS FED WITH A PERMANENT LIVE, IF THE ELEMENT WINDING FAILS TO EARTH, IT WILL USE THE EARTH AS A NEUTRAL AND THEREFORE NEVER SWITCH OFF. NOTE, IF THE RED LED ON PCB IS ILLUMINATED THIS IS NOT THE FAULT. (IF AN RCD IS FITTED IT WILL DETECT THE EARTH LEAKAGE AND DISABLE THE SUPPLY TO THE BOILER)

• LEAKING THERMISTOR POCKET. IF THE POCKET IS FLAWED AND ALLOWS MOISTURE TO ENTER THE POCKET THE UNIT CAN DO ONE OF THREE THINGS, OVER BOIL, OVERFLOW OR OPERATE AT LOW TEMPERATURE . WHEN OVER BOILING REMOVE THE TWO BLUE WIRES FROM THE PCB AND FIT A DIRECT SHORT ACROSS THE TERMINALS ON THE PCB, IF THE ELEMENT NOW TURNS OFF, THIS IS PROBABLY THE FAULT. CHANGE THE ENTIRE POCKET ASSEMBLY. THE RESISTANCE OF THE THERMISTOR AT BOILING POINT IS APPROX 1K OHMS AND AT 20 DEGREES 14/15 K OHMS.

• PRINTED CIRCUIT BOARD FAULTY. AND/OR TRIAC BURNT OUT (SOLD AS A PAIR)

FAULT SCENARIO 2 - BOILER OVERFLOWING OR INDICATING IT IS OVERFILLING (ALL BOILERS EXCEPT CB & CB/S)

NOTE: INDICATED BY A 4-PULSE SIGNAL FROM THE SERVICE LIGHT OR JUST FLASHING ON KUDOS MODELS

• DEBRIS TRAPPED IN THE SEAT OF THE SOLENOID VALVE STOPPING THE VALVE FROM SEALING. EVENTUALLY WATER WILL DRIP FROM THE OVERFLOW. CLEAN THE VALVES INLET FILTER AND WORK THE BOILER. THIS WILL NORMALLY CLEAR THE DEBRIS AND THE BOILER WILL FUNCTION OK.

• SCALE ON NORMAL LEVEL SENSOR PROBE (PARTICULARLY CASCADE, COMPACT AND QUANTUM MODELS)

• IF WATER IS FLOWING FROM THE OVERFLOW (AS OPPOSED TO DRIPPING), A LEAKING THERMISTOR POCKET COULD BE THE PROBLEM. IF THIS IS THE CASE THE UNIT CAN DO ONE OF THREE THINGS, OVER BOIL, OVERFLOW OR OPERATE AT LOW TEMPERATURE. WHEN OVERFLOWING, REMOVE THE TWO BLUE WIRES FROM THE PCB. IF THE SOLENOID NOW TURNS OFF, THIS IS THE FAULT. CHANGE THE THERMISTOR AND POCKET AS A PAIR. THE RESISTANCE OF THE THERMISTOR AT BOILING POINT SHOULD BE APPROX 1K OHMS AND AT 20 DEGREES 14/15 K OHMS.

• IF THE YELLOW LED ON THE PCB IS ILLUMINATED THE PRINTED CIRCUIT BOARD COULD BE FAULTY

• ON KUDOS MODELS EXCESSIVE WATER FLOW RATE THROUGH THE SOLENOID VALVE CAN CAUSE IT NOT TO CLOSE. IF THIS IS THE CASE, REPLACE THE SOLENOID VALVE AND/OR RESTRICT THE FLOW RATE TO THE BOILER

FAULT SCENARIO 3 - LOW OPERATING TEMPERATURE (ALL BOILERS EXCEPT CB & CB/S)

• WATER BOILS AT DIFFERENT TEMPERATURES DUE VARIATIONS IN BAROMETRIC PRESSURES. WATER CAN BOIL AT 98 DEGREES IF THE BAROMETRIC PRESSURE IS LOW. THE WATER TEMPERATURE AT THE TAP (TESTED IN THE WATER FLOW FORM THE TAP, NOT IN A CUP) SHOULD NOT BE NO HIGHER THAN 98 DEGREES CELCIUS. TUNED HIGHER THAN THIS, THE BOILER IS LIABLE TO TRIP THE THERMAL CUT-OUT WHEN BAROMETRIC PRESSURE IS HIGH.

• FAULTY THERMISTOR AND/OR THERMISTOR POCKET. IF WATER IS WELL BELOW 98 DEGREES AND THE READY LIGHT ON THE FRONT OF THE MACHINE IS A SOLID COLOUR, AS OPPOSE TO FLASHING, THIS MAY BE THE FAULT. CHANGE THE THERMISTOR AND POCKET AS A PAIR.THE RESISTANCE OF THE THERMISTOR AT BOILING POINT SHOULD BE APPROX 1K OHMS AND AT 20 DEGREES 14/15K OHMS.

• THE ELEMENT MAY HAVE FAILED AND THE UNIT IS COOLING DOWN.

• THE POTENTIOMETER MAY BE SET TOO LOW. CONTACT CALOMAX FOR FURTHER ADVICE.

FAULT SCENARIO 4 - BOILER NOT HEATING AT ALL (ALL BOILERS EXCEPT CB & CB/S)

• CHECK THE STATE OF THE WAIT/READY LIGHT ON THE FRONT OF THE BOILER. IF IT IS FLASHING THE BOILER IS BELOW FULL OPERATING TEMPERATURE AND THE ELEMENT SHOULD BE ON. CHECK THE RED 'LED' IS LIT ON THE PCB. IF IT IS, THE ELEMENT MAY HAVE FAILED. CHECK THE ELEMENT FOR CONTINUITY.

• IF THE ELEMENT IS OK, THE MAIN PRINTED CIRCUIT BOARD AND/OR TRIAC PCB MAY BE FAULTY (SUPPLIED AS A PAIR)

• NOTE: THE ELEMENT IS FED WITH A PERMANENT LIVE AND THE NEUTRAL IS SWITCHED, SO TO CHECK FOR 240V ACROSS THE ELEMENT, IT MUST BE DONE BETWEEN THE TWO ELEMENT WINDINGS.

FAULT SCENARIO 5 - BOILER NOT FILLING (ALL BOILERS EXCEPT CB & CB/S)

• KUDOS RANGE
• CHECK THE STATE OF SERVICE LIGHT ON THE FRONT OF THE BOILER. A SOLID GREEN LIGHT INDICATES THE TANK SENSOR HAS NOT DETECTED WATER FOR 30 SECONDS (NOT AVAILABLE ON EARLY KUDOS). IN THIS MODE THE UNIT WILL OPERATE IN ECONOMY i.e. BOTTOM THERMISTOR DISABLED. WHEN THE WATER SUPPLY TO THE UNIT IS RE-INSTATED, THE SERVICE LIGHT WILL EXTINGUISH AND THE BOTTOM THERMISTOR WILL BE ENABLED. IF LEFT IN THIS 'DRY' STATE FOR SOME TIME, THE SOLENOID VALVE MAY FAIL AND DAMAGE THE PCB. A GOOD SOLENOID COIL SHOULD HAVE A RESISTANCE OF APPROX 3.7K OHMS. IF IT IS SIGNIFICANTLY LOWER THAN THIS, IT IS FAULTY. REPLACE BOTH THE PCB AND SOLENOID VALVE AS A PAIR IF THIS IS SUSPECTED TO BE THE CASE.

• ALL OTHER MODELS (EXCEPT KUDOS, CB & CB/S)
• CHECK THE STATE OF SERVICE LIGHT ON THE FRONT OF THE BOILER. A SOLID GREEN LIGHT INDICATES THE UNIT HAS BEEN STARVED OF WATER FOR A LONG PERIOD OF TIME (NOT AVAILABLE ON EARLIER MODELS). IF THE SOLENOID IS 'DRY' FOR LONG PERIODS, IT COULD OVERHEAT AND FAIL. IF THE SOLENOID FAILS IN THIS MANNER IT WILL DAMAGE THE PCB. A GOOD SOLENOID COIL SHOULD HAVE A RESISTANCE OF APPROX 3.7K OHMS. IF IT IS SIGNIFICANTLY LOWER THAN THIS, IT IS FAULTY. REPLACE BOTH THE PCB AND SOLENOID VALVE AS A PAIR IF THIS IS SUSPECTED TO BE THE CASE.