IF YOUR BOILER HAS A PROBLEM AND YOU HAVE NO HOT WATER THEN THE
FAULT COULD BE ANYONE OF THE FOLLOWING PROBLEMS, WE HAVE LISTED THE MOST OBVIOUS
FAULTS FOR COMBINATION BOILERS AND ALSO
FOR CONVENTIONAL BOILERS WITH SEPARATE HOT WATER CYLINDERS. PLEASE NOTE THAT THE
LIST WILL NOT COVER EVERY BOILER, BUT WILL GIVE A GOOD INDICATION TO MOST
PROBLEMS, THIS INFORMATION WILL BE UPDATED REGULARLY AND IS BASED UPON 25 YEARS
OF EXPERIENCE IN DEALING WITH BOILER FAULTS AND KNOWN PROBLEMS.
REGULAR CONVENTIONAL BOILERS WITH A SEPARATE HOT WATER CYLINDER
IF THE HEATING IS WORKING BUT THE HOT WATER IS NOT, THEN
THE FAULT IS EITHER THAT THE MOTORISED VALVE IS NOT WORKING, THIS WILL EITHER BE
A 3 PORT VALVE , OR YOU MAY HAVE 2 X 2 PORT VALVES, THIS VALVE OPENS WHEN THERE
IS A DEMAND FROM THE PROGRAMMER, WHICH SENDS A SIGNAL TO THE HOT WATER
THERMOSTAT , THE HOT WATER THERMOSTAT THEN SENDS A SIGNAL TO THE VALVE. CHECK
IF YOU ARE GETTING 240 VOLTS FROM THE
PROGRAMMER, IF NOT THEN THE PROGRAMMER IS FAULTY, IF YOU ARE CHECK THAT THE HOT
WATER CYLINDER STAT IS GIVING 240 VOLTS TO THE MOTORISED VALVE, VIA THE WIRING
BOX. IF NOT THEN THE STAT IS FAULTY. IF YOU ARE GETTING 240 VOLTS THEN THE
MOTORISED VALVE IS PROBABLY FAULTY. THESE VALVES OFTEN NEED REPLACING , SOME
PEOPLE JUST CHANGE THE MOTOR, BUT THIS IS A WASTE OF TIME, AS NORMALLY THE PART
THAT MOVES INSIDE THE VALVE BECOMES STIFF AND CREATES EXCESS LOADS ON THE MOTOR,
WHICH IN TURN CAUSES THE MOTOR TO FAIL. REPLACEMENT OF THE ENTIRE VALVE IS THE
BEST OPTION AND THIS MEANS A COMPLETE DRAIN DOWN OF THE SYSTEM. IF YOU ARE NOT A
QUALIFIED ENGINEER THEN IT IS BEST LEFT TO THE EXPERTS.
IF ALL OF THE ABOVE IS OK AND SEEMS TO WORK THEN IT COULD BE
THAT THERE IS A BLOCKAGE IN THE PIPEWORK CONNECTED TO THE CYLINDER COIL
FLOW/RETURN PIPEWORK, WHICH IS STOPPING THE HEAT GETTING TO THE CYLINDER. MOST
BLOCKAGES ARE CAUSED BY IRON OXIDE SLUDGE AND WILL NEED TO BE POWER FLUSHED TO
BE REMOVED, THIS REQUIRES A POWER FLUSHING MACHINE SUCH AS THE ONE WE USE
WHICH IS A KAMCO AND CAN TAKE A FULL DAY TO CLEAR.
COMBINATION BOILER HOT WATER PROBLEMS.
THE MOST OBVIOUS FAULT WITH COMBINATION BOILERS WHEN THERE IS
HEATING BUT NO HOT WATER IS
THAT THE DIVERTER VALVE IS NOT WORKING. WHEN YOU OPEN THE TAP, PRESSURE IS
APPLIED TO A DIAPHRAGM
IN THE DIVERTER VALVE, THIS PUSHES OUT A PIN, THE PIN ACTIVATES A MICRO SWITCH
AND THE BOILER FIRES UP.
IF YOU KNOW WHERE TO LOOK IT IS NORMALLY QUITE EASY TO SEE WHETHER THE PIN IS
MOVING WHEN THE HOT WATER TAP IS OPENED, IF IT IS NOT THEN THE VALVE OR
DIAPHRAGM WILL NEED REPLACING.
ANOTHER FAULT ON COMBINATION BOILERS IS THE HOT WATER THERMOSTAT OR THERMISTOR, THESE VARY FROM BOILER TO BOILER, AND THERE ARE TOO MANY TO LIST HERE, BUT THEY NEED TO BE CHECKED FOR CORRECT OPERATION.
ANOTHER COMMON PROBLEM IS THE SECONDARY HEAT EXCHANGER, THIS CAN
BECOME SCALED UP IN HARD WATER AREAS, IF YOU LIVE IN A HARD WATER AREA YOU
SHOULD HAVE A SCALE INHIBITOR FITTED TO THE BOILER TO PREVENT THIS. THEY CAN
ALSO BLOCK UP WITH IRON OXIDE SLUDGE, WHICH WILL PREVENT THEM FROM HEATING THE
WATER UP TO THE CORRECT TEMPERATURE. TO CURE THIS THE HEAT EXCHANGER WILL EITHER
HAVE TO BE REPLACED OR REMOVED, CLEANED AND REFITTED. IF THERE IS SLUDGE IN IT
THEN YOU NEED TO ASK YOURSELF
WHERE HAS IT COME FROM? THE OBVIOUS ANSWER IS FROM THE RADIATOR SYSTEM, SO THIS
WILL ALSO NEED TO BE CLEANED OR YOU CAN INSTALL A FILTER LIKE A MAGNACLEAN OR
FERNOX TF1 ONTO THE RETURN PIPE TO
THE BOILER TO PREVENT THE SAME THING FROM HAPPENING AGAIN.
SOMETIMES IF THERE IS IRON OXIDE SLUDGE OR SCALE IN THE SYSTEM IN CAN GET INTO THE MAIN HEAT EXCHANGER, SECONDARY HEAT EXCHANGER AND OTHER PARTS OF THE BOILER, IF THIS IS THE CASE YOU MAY HAVE TO REPLACE SEVERAL PARTS OR POWERFLUSH THE BOILER AND SYSTEM. WE HAVE SEEN BOILERS WITH MULTIPLE FAULTS, WHERE THE DIVERTER VALVE IS NOT SHUTTING OFF THE CENTRAL HEATING CIRCUIT COMPLETELY AND WHEN YOU OPEN THE HOT WATER TAP SOME OF THE HEAT GOES TO THE CENTRAL HEATING INSTEAD OF THE HOT WATER CIRCUIT WHICH PREVENTS THE HOT WATER FROM REACHING THE CORRECT TEMP.
YOU MAY FIND THAT ONLY WHEN YOU HAVE REPLACED 1 PART ANOTHER FAULT SHOWS UP, SOMETIMES THIS IS NOT EVIDENT UNTIL AFTERWARDS AND WITH HINDSIGHT IT MAY BE BETTER TO REPLACE THE ENTIRE BOILER.
OTHER PROBLEMS ARE FAULTY PRINTED CIRCUIT BOARDS, WIRING AND INCORRECT/FAULTY GAS VALVES, PRESSURES.
ALL UK GAS BOILERS REQUIRE A GAS SUPPLY PRESSURE OF 20 MB FROM THE GAS METER, THE GAS METER HAS A REGULATOR FITTED THAT REDUCES THE INCOMING GAS SUPPLY TO 20 MB, AND THE REGULATOR KEEPS IT AT THIS PRESSURE DEPENDING ON DEMAND. SOMETIMES THE REGULATOR FAILS, AND THE PRESSURE DROPS QUITE LOW, THIS WILL CAUSE A DROP IN PRESSURE AT THE BURNER ON THE BOILER, WHICH WILL HAVE A ADVERSE EFFECT ON THE POWER OUTPUT FROM THE BOILER AND THEREFORE THE BOILER WILL NOT BE ABLE TO HEAT THE HOT WATER TO THE CORRECT TEMPERATURE. THIS CAN BE TESTED BY A GAS SAFE ENGINEER.
THE BOILER HAS A GAS CONTROL VALVE WHICH FURTHER REDUCES THE
PRESSURE, TO THE MAIN BURNER,
THIS PRESSURE NEEDS TO BE CHECKED TO SEE IF IT IS CORRECT, MOST CAN BE ADJUSTED,
OR IT MAY BE THAT
THE VALVE OR SOLENOID ARE FAULTY AND NEED REPLACING.
MOST CONDENSING BOILERS HAVE WHAT ARE CALLED ZERO RATE GOVERNORS AND IT IS NOT POSSIBLE TO TEST THE BURNER PRESSURE, INSTEAD YOU WILL NEED TO CHECK THE POWER RATING BY TIMING THE GAS USED OVER A FEW MINUTES TO FIND OUT THE KW RATING. AND THEN COMPARE IT TO THE DATA BADGE.
SOME NEW BOILERS POWER RATINGS ARE GOVERNED BY THE FAN SPEED, IF THE SPEED SLOWS DOWN THEN THE AMOUNT OF GAS BEING BURNT WILL REDUCE , WHICH CAN RESULT IN LOWER WATER TEMPERATURES.
PLEASE NOTE THAT YOU MUST BE GAS SAFE REGISTERED TO WORK ON ANY GAS APPLIANCES!!
IF YOU ARE NOT THEN PLEASE LEAVE IT TO THE PROFESSIONALS, WE ARE
GAS SAFE REGISTERED SO PLEASE
CALL US AND WE CAN HELP YOU.
CALL NOW 07836729376 / 020 84739098