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Maintenance and Service

Exam revision materials for Plumbing Level 2&3 and ACS Gas Safety test

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HUB-001A-WAX Vado Thermostatic Cartridge


Hudson Reed




S960134NU Thermostatic Cartridge

Sirrus Rothwell R995 Antique Shower








Alfa Laval






Electroheat PLC





Heat Lline








Saunier Duval


Viessmann Vitodens 100 W Compact



Space Heaters




Armitage Shanks





Bathstore Thermostatic Cartridge

Servicing Guide



Thermal Store Cylinders


Underfloor Heating





Hot Water Cylinders




Gas Safety Inspection

Gas Flue Analysers

Gas Hobs



Glowworm Betacom c24 - Faulty Diverter valve - 0020064049

Glowworm Betacom c24 radiators are getting hot when hot water is running and the hot water is lukewarm

  • Remove a diverter vale motor and try to push a spindle on the divert valve
  • If spindle doesn't come back or doesn't push then replace the diverter valve
  • The replacement part number is 0020064049 
  • While replacing the diverter valve check the secondary (hot water) heat exchanger for sludge. Clean if necessary to fix the problem with lukewarm hot water.
  • Sludge in the system is the main reason for a Diverter valve to fail
  • The whole system powerflush will be advisory.
< Go Back2017-05-06

Glowworm Betacom 24 - leaking Glowworm Water Cock 22mm 0020027544

Glowworm Water Cock 22mm 0020027544 under the boiler is leaking.

2 valves on the left-hand side are central heating service valve and the over time can develop a leak.

They can not be repaired and require replacement. 

< Go Back2017-01-20

Glowworm Betacom 24c - PCB 0020061654

GLOWWORM Betacom 24C 30C

  • The radiators are getting hot when hot water is operated
  • The diverter valve faulty OR
  • Diverter motor is faulty OR
  • PCB is faulty. Check voltage on a diverter motor
    • voltage 240V AC between 1 and 2 for heating
    • voltage 240V AC between 2 and 3 fir hot water
  • Replacement part PCB 0020061654 
< Go Back2016-06-25

Glowworm Flexicom 18HX - F70 fault code. Faulty display

Glow-worm Flexicom 18hx boiler display doesn't work

  • The display shows constantly "88"
  • The display PCB needs to be replaced. The part number is 0020023826 
  • After the PCB replaced the error code F70 will appear which means incompatible software
    • To fix the issue follow next steps:
    1. Press MODE and "+" for 5 seconds to enter the installers mode
    2. choose 35 press MODE for 5 seconds
    3. choose L2 press MODE for 5 seconds
    4. choose 93 press MODE for 5 seconds
    5. choose 5 and reset the boiler (if already 5 the n choose 1 reset the boiler and do all again)
< Go Back2016-04-15

Glowworm Xtrafast - faulty timer 57245

Timer replacement part number 57245

< Go Back2016-03-25

Glowworm 35CI - Faulty timer 2000800089

Glowworm 35CI combi boiler timer doesn't work

Replace the timer

Replacement part number is 2000800089

< Go Back2016-03-25

Glowworm British Gas 330 - Fault code F5

Open vent boiler Glowworm British Gas 330 is not firing and displays erro code F5 after 10-20 seconds

  • F5 error code means overheat lockout
  • Manual reset is required
  • Open the boiler casing and press the red button on the overheat thermostat in the top left corner of a sealed chamber
  • Also:
    • get rid of the air locks in the system
    • check a circulation pump
    • clean any in-line strainers on the return pipe to the boiler
    • check and fit a by-pass valve if missing
< Go Back2015-01-30

Glowworm 38cxi - Filling Loop 2000802600 replacement

Glow Worm 38cxi combi boiler doesn't work due to low pressure. When I try to open a filling loop to let some more pressure in the water starts pouring from a non return valve right on the floor under the boiler.

  • The problem is a faulty non-return valve which is a part of the filling loop
  • The filling loop needs replacement
  • Isolate the flow and return valves and drain the boiler before replacing the filling loop
  • The replacement part is Glow Worm Filling Loop 2000802600
< Go Back2014-08-18

Glowworm 24 CXI is constantly leaking from many places

Glowworm 24 CXI combi boiler is leaking from different places under the boiler. In my case it was only one leak from a flow sensor.

  • The flow sensor had a little crack and when I replaced O-rings (part number 2000801950) it was still leaking
  • Need to replace the whole part. The part number is 2000801910 
  • You will need to isolate the cold water supply to the boiler only
< Go Back2013-10-07

Glowworm 30SXI - repair boiler loosing pressure

Glowworm 30SXI - water is constantly dripping from the discharge pipe outside the property causing damage.The system is overpressurised (3 bar) and safety valve releasing the excess pressure through the safety valve. To check the system pressure you need to turn the heating and hot water off at your programmer then boiler's display will start showing the pressure. If system pressure is around 3 bar then check that a filling loop is closed and not letting by. Then drain the boiler down (isolate flow and returns under the boiler) and check the pressure of the expansion vessel. If below 1.5 bar then pump it up to 1.5 bar with any bicycle pump. Refill the system and if water still constantly dripping from the discharge pipe even when the boiler is cold then a Safety Valve need replacement.

The part number for replacement is 0020047005 (old part number: 2000801904) and you can order it from here.

Glowworm 30SXI manual: PDF

< Go Back2013-04-13

Glowworm Ultimate 40FF

Glowworm Ultimate 40FF - boiler doesn't work and makes a buzzing sound. Last night my Gloworm Ultimate 40FF boiler has given up the ghost. It only now makes a faint humming noise when switched on which I guess is the electricity just activating the system. I only have neon lights 1 and 2 illuminated in the PCB. That leaves 3 and 4 which are not illuminated. These indicate failed airflow (light 3) and Ignition (light).
The night before when it was working. It did sound a little noisier than usual. A bit like the fan was in need of lubrication.

Check the fan isn't stuck. You need to remove the combustion chamber front, which is really a job for a corgi guy. Once removed, the seals need to be checked and once replaced it needs checking so as to ascertain a correct seal. Give the fan a nudge and if it start spinning but makes the loud noise then lubricate it if the noise hasn't gone then it's better to replace the fan.

The part number for replacement is 2000800431 and you can order it from here.

Glowworm Ultimate 40FF manual: PDF

< Go Back2013-04-07

Glowworm 30 CXI - fault F13

30 CXI - no heating and no hot water. The fault code F13 is on the display means it is a PCB connection problem. Clean and check the board and harness, if no faults then the fault is with the Relay towards the front of the board, the contacts have started to weld themselves, a gentle tap on the top and it all works. After this I replaced the 10A contact relay with a gold plated 16A rated type. Although its slightly taller and you had to cut the protective plastic cover to fit it in. Or the PCB replacement might be considered.

The part number is 4000124180 and you can order it from here.

Glowworm 30 cxi manual: PDF

< Go Back2013-04-03

Glowworm Betacom 30C - hot water is intermittent

Glowworm Betacom 30C - hot water is intermittent. Open a hot water tap and watch the boiler operation. If the boiler fires up and goes off intermittently but doesn't do the same in central heating mode then the hot water thermistor or a plate heat exchanger are faulty. Contact the manufacturer to find out how to test the thermistor and it its working OK then replace or clean the plate heat exchanger.

The part number is 0020061615 and you can order it from here.

Glowworm Betacom 30C manual: PDF

< Go Back2013-03-30

Glowworm Xtramax HE

Combination boiler Glowworm Xtramax HE with a hot water storage cylinder discharges a lot of water from the Temperature and Pressure Relief Valve (T&PRV). After I turned the power on and put a hot water demand approximately after 10 seconds when a secondary, hot water pump start working but all hot water taps are closed and water in the storage cylinder is cool the top T&PRV start discharging lots of water continuously.

  1. First check that the hot water expansion vessel which is located in the bottom right corner of the boiler is charged with air up to 3.5 bar. There is only one screw is holding it. Remove the cup from the nipple and press. If water start coming from the nipple then you need to replace the expansion vessel.
  2. If expansion vessel is OK then replace the T&PRV. The part number is 0020018589. Not many suppliers keep this in stock. It is going to be a special order which might take up to 4 working days. You can order it from here.

Boiler manual: PDF

< Go Back2013-03-14