Troubleshooting Manual

The trouble shooting manual is linked below, with an easy PDF download Troubleshooting Manual Glow Worm. This manual provides a step-by-step process for fault finding in the glow worm combi boilers, as well as information on replacing parts and troubleshooting basic issues.

Attention! It is important that the warnings be followed when conducting specific troubleshooting options and that only glow worm authorized replacement parts be used on any replacement jobs. It is equally important to ensure any modifications or alterations are made by a competent individual who is either a glow worm specialist or someone equally well certified (Gas Safe Registered), as a matter of safety.

Included in this download are charts and pictures helping to depict the interior layout of each component within the glow worm products. There is also a list of electrical problems and corresponding electrical parts necessary for replacement, making it easy to order exactly what you need.

Annual service

All boilers require some modicum of maintenance at one point or another. That maintenance can range from a simple servicing task to a faultfinding electrical issue, or even a simple replacing of existing parts once they age. Contained in this troubleshooting manual are instructions on how to handle all three.Servicing your boiler is easily done at home following these simple steps.

Troubleshooting manual

Each Glow Worm Combi boiler has an on-board fault diagnostic system with LCD display. Whenever a fault occur on the boiler, the warning LED lamp/sign at the top of the user display will illuminate and the LCD display will indicate the precise area where the fault has occurred. Error message will be displayed.

Table 1. Standard error codes applicable for all Glow-warm Combi boilers

ERROR CODE FAULT DESCRIPTION
02 FF AIR FLOW SAFETY
04 FF NO IGNITION, MAX. IGNITION TIME= 7 SECONDS
05 FF OVERHEATING LOOP
06 FF HEATING THERMISTOR ON FLOW PIPE
07 FF DOMESTIC THERMISTOR ON DHW PIPE
08 FF TEMPERATURE ON STORAGE VESSEL
09 FF LOSS OF WATER PRESSURE SENSOR
12 FF USER INTERFACE
13 FF MAIN CONTROL BOARD PCB
14 FF TEMPERATURE LIMITER CONTROLLED BY HEATING THERMISTOR ON THE FLOW PIPE
15 FF STEP MOTOR FAILURE
16 FF SAFETY GAS LEAK THROUGH THESAFETY ELECTRIC VALVES
17 FF NETWORK VOLTAGE TOO LOW
20 FF COMMUNICATION FAULT
21 FF LACK OF WATER IN THE PRIMARY CIRCUIT

Table 2. Non-error code related faults applicable for all Glow-warm Combi boilers

FAULT ACTION
NO HEATING THERE IS DEMAND BY THE ROOM TEMPERATURE THERMOSTAT. CHECK ALL THE CONNECTIONS. IF FAULT PERSISTS, REPLACE MAIN CONTROL BOARD (PCB).
NO HEATING. NO DISPLAY OF RADIATOR SYMBOL. CHECK THAT CONTACT 1 IS ON 1. OR MEASURE A RESISTANCE< 10 ohms BETWEEN B5.1 AND B5.2. CHECK ROOM THERMOSTAT CONNECTIONS OR MEASURE A RESISTANCE < 50 ohms BETWEEN B3.1 AND B3.2.
WATER NOT HOT ENOUGH, OR UNEVEN FLOW FROM TAP. THERE IS A HOT WATER DEMAND. CHECK THREE WAY VALVE. CHECK THREE WAY VALVE MOTOR (SWITCHING). CHECK THE DIRECTION OF CLIP ON THREE WAY VALVE
WATER NOT HOT ENOUGH OR UNEVEN FLOW FROM TAP. NO DISPLAY OF TAP SYMBOL READ THE VALUE OF FLOW RATE DETECTOR ON CODE 07 OF INFO MENU. IT WILL READ HOT WATER OUTPUT (L/MIN.)(x10) VALID RANGE 00,,,199 NOTE: DIVIDE THE VALUE BY 10. IF = 0 THE DETECTOR IS BLOCKED OR THE MAIN CONTROL BOARD (PCB) HAS FAILED.
THE BURNER COMES ON WHEN COLD WATER IS DRAWN OFF CHECK THAT THE HOT WATER CIRCUIT HAS BEEN BLED PROPERLY (ANY AIR BUFFER MAY ACTIVATE THE FLOW RATE DETECTOR WHEN THE TAPS ARE TURNED ON).

Search for the specific issue you are trying to troubleshoot and follow the steps below:

Combustion Chamber and Heat Exchanger

If you are facing problems with the combustion chamber and heat exchanger there are simply serving steps which can be applied to rectify the problem without calling in a professional.
The first step is to remove any loose debris from the combustion chamber. This can be done with a soft brush and any hand or other vacuum cleaner. Once this is done, carefully flush the remaining debris away with a spray bottle or other type of water spraying device. You want to ensure the water is kept far from any electrical components, but that it removes the remaining debris in the condensate trap.

image 1 ff

If you need to make additional adjustments, proceed as necessary. It is rare that the carbon dioxide levels need to be reduced, but if so, adjust carefully. Rotate the “service” potentiometer completely clockwise and re- check the maximum rate combustion. This rate should show 9.1% + 0.2 -0.5. Once you have checked this, replace the cap and refit the control cover back on the rear panel.

After that, rotate the “service” potentiometer again anti- clockwise. Hold it in this position for 5 seconds and then rotate it clockwise, or to the mid-point position. At this point the fan should be reduced and flash “12” on the screen.

Check the CO value which should read 9.1% + 0.2 – 0.5. The inner case front panel should read a slight increase for the combustion.
Natural gas should read 9.3% + 0.3 – 0.5
Propane gas should read 10.7% + 0.3 – 0.8

Condensate Drain

When you are servicing the boiler, it is not often that the condense drain needs to be removed. Instead, you can simply flush the condense drain by pouring water into your heat exchanger and watching to ensure the water flows freely from the drain. If you see that the condense drain is blocked, you can remove it (the instructions for which are included later).

Combustion Check

To complete a combustion check, you need to reassemble all parts of the boiler except for the front and inner casing panels. With that done, you should connect a CO combustion analyser to the test point. You can find the test point on the fluelbow. From there, turn on the gas service cock.
Once the power is off and your appliance is cold, you should unclip the controls fascia and hinge down the controls to find the potentiometers. These are near the rear of the user interface. Be careful not to let the fascia drop down or it can damage the wiring.
Turn the electrical supply on. Make sure the external controls are calling for heat. At this point the boiler should begin firing automatically. Let your boiler to fire for at least 60 seconds after which you should take an electrical screwdriver and rotate the “service” potentiometer completely clockwise. Doing this will allow your digital display to show the “flashing” fan speed on the fascia. Once it is in the fully clockwise position, your display should indicate the maximum fan speed. The maximum is contingent upon the boiler type (271 for 12hxi, 32 1 for 15hxi, 411 for 18hxi, 471 for 24hxi and 571 for 30hxi and 38hxi). Once this is done, check the CO value, which should read 9.1% +0.2 -0.5.
It is important to note that the inner casing panel which is fitted to the combustion readings might increase slightly. If you need to make an adjustment, do so. Any adjustments made to the gas valve need to be completed by someone who is a competent professional.
Adjust the maximum CO, ensuring the throttle is 9.1%. To do this, rotate it anti-clockwise.

 

fault finding 2 ff

Inner Casing Panel Seal Check

In order to service the inner casing panel you must check the condition of the seal and replace it as required. To replace it, remove the old seal and thoroughly clean the casing services. Once this is done, fit the new seal into the area and make sure it is the correct link for the boiler type. If it is not the correct length it will not fit.
If you are facing problems with the faults, and need to conduce fault finding, there are simply serving steps which can be applied to rectify the problem without calling in a professional.
Please note that before operating your boiler make sure that you opened a gas supply and that it is purged of air.

WARNING! Always isolate your boiler from the electrical supply prior to carrying out any electrical work. Once you have completed your work be sure to check for gas soundness.

Electrical Testing

If you have any doubt about the voltage supply to any component on the boiler you can carry out a simple electrical test.

Important. Upon completion of the faultfinding tasks required, you have to make sure that any task which required the breaking and making of electrical connections to the earth continuity, polarity, short-circuit, and resistance to earth checks is repeated with a multimeter tool.

In order to complete this electrical test you must hinge down the control box and remove the screws to unhook the rear panel. Once this is done you should refer to the fault finding charts below.

faut codes 1.jpg

fault codes 2.jpg

 

 

Replacing Parts

Important Notes
When you are replacing a part on this appliance, you should only use spare parts which you know conform to the safety and performance specifications required by the company.
Using reconditioned parts or copy parts which are not authorized by the company can result in malfunctions and further damage.
Replacing different parts should be carried out by a competent individual if not a professional. Prior to replacing any parts on the boiler, you should isolate the boiler from the mains electric supply and you should turn off the gas at the service cock located on the boiler.

Unless stated otherwise, you should replace the parts in the reverse order of their removal. It is important that this be carried out strategically.

After you have replaced any part you should always test the gas for sound operation and carry out any functional test for the controls as necessary.
For replacing parts on the casing panel, the inner casing panel as well as the chassis front panel have to be removed according to the instructions contained in this troubleshooting manual. It is important to remove the two screws located on the underside of the front casing and then remove the two screws on the front of the inner front panel before you lift the panel off the boiler. Once all four screws from the chassis front are removed you can pull it out at the top from any remaining slots.
Please note that when you are replacing the chassis front panel, you must make sure that the bottom fits behind the exposed lip. The side panels can be hinged sideways in order to help you replace any part. Make sure to remove the three screws which secure each side panel to the boiler , two of which are located at the front and one of which is located at the top.

Spark Electrode replacement

To replace the spark electrode you must start by removing the spark plug lead, the earth lead, and the two securing screws. Once this is donethe spark electrode should be withdrwned from its combustion chamber. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Igniter Unit replacement

To replace the igniter unit on your boiler, remove the ignition lead as well as the electrical connections carefully. Then remove the ignitor unit by first removing the two securing screws and replacing it as necessary. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Ignition Lead replacement

To replace the ignition lead you should pull the spark plug style connector off of both the spade connector and the spark electrode. Both of these are connected to the ignitor unit. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Gas Valve replacement

To replace the gas valve start by removing the electrical plug from the gas valve according to the diagram. After this carefully remove the fan, the gas valve, and the burner assembly. Before you remove the gas valve take note of its current position on the fan. After this removes the three securing screws which hold the gas valve in place. You will see that these screws secure the gas valve and the plastics for a plate to the fan.

gas valve
Once this is done remove the gas valve. Next, remove the gas supply pipe from the gas valve. When you are refitting the gas valve make sure that you exercise caution, as it can be fitted in more than one way. Once you have assembled the replacement parts be sure to test the gas for soundness. When installing the replacement part, make sure it is an approved Glow Worm replacement part.

Fan replacement

To replace the fan start by removing the electrical plug. Carefully remove the fan, gas valve, and burner assembly. Once this is done remove the gas valve as described above and any relevant parts attached to it. Following this you must unscrew the three screws holding the venturi plate to the fan. Remove the two screws which hold the fan to the gas manifold next. Check to see if the gasket is in working order and replace it if necessary.

Please note that the 30 HXI as well as the 38 HXI fan is secured by way of an extension piece which has to securing screws. If you are working on either of these models you need to check and see if the seals or the gaskets need replacing as well. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Burner replacement

To replace the burner, carefully remove the fan, gas valve, and burner assembly. Remove the four screws which hold the burner in place and complete your replacement installation as necessary. Please note that the burner requires a new gasket if it is refitted. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Front Insulation replacement

To replace the front insulation start by removing carefully the fan, gas valve, and burner assembly. Remove the burner as mentioned above, and further remove the spark electrode as mentioned above. Much the same as the burner, you will need a new gasket when refitting the front insulation. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal. Conduct any functionality or operational tests as needed.

Rear Insulation replacement

To replace the rear insulation carefully remove the fan, gas valve, and burner assembly. Remove the securing screw as well as the washer located in the center of the insulation . Remove the insulation and replace as necessary. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Viewing Window replacement

To replace the viewing window remove the circling, followed by the steel washer, and the glass. Next, remove the fiber washer and replace the viewing window in reverse order. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and
conduct any functionality or operational tests as necessary.

Heat Exchanger replacement

To replace the heat exchanger start by carefully removing the fan, gas valve, and burner assembly. Drain the boiler after this and remove the clip which secures the clear condensed pipe to the heat exchanger. Next, pull and remove the clear condense pipe from the bottom of the heat exchanger. There will be two nuts on the flow and return pipes from the heat exchanger, both of which must be removed after which the pipes can be moved from the heat exchanger.

heat exchanger

Once this is done you must unscrew the three screws that secure the heat exchanger as well as the clamps located at both bottom and the top. This will allow you to remove the heat exchanger itself.

Please exercise caution when doing this, as there is water in the heat exchanger. Finally, remove the clear condensed pipe connector from the bottom of the exchanger. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Flue Hood replacement

To replace this you must remove the heat exchanger as mentioned above. Once this is done in accordance with the rules mentioned above, remove the two securing screws and pull the hood down and away from the hood bracket and elbow. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

 

Heating Return Thermistor replacement

thermistor

To replace the heating return thermistor start by removing the electrical connections from the thermistor. After this, remove the retaining clip from your flow pipe. Remove your thermistor from the retaining clip. Much the same as the heating flow thermistor, the polarity of the wiring serves no importance in this process. For more information you can look to the diagram opposite the instructions. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Overheat Thermostat replacement

If you need to replace the overheat thermostat, start by removing the electrical connections from your overheat thermostat. Once this is done the move the retaining clip connecting to the flow pipe. Finally, remove the overheat stat from your retaining clip. Please note that when you are fitting your new thermostat, you need to make sure that it is located correctly onto the flat area of your pipe and that the retaining clip remains secure. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Condensate Drain replacement

If you are replacing your condensate drain, start by removing the clips which security flexible tubes to the siphon adapter. This is done by twisting the clips ever so slightly so as to disengage the clip jobs from one another. Once this is done remove the black flexible tubes from your siphon adapter. Lift off your siphon adapter. The drain downstream connection  should be with-drowned of the trap. Carefully remove the two condense traps securing screws. You should then remove the condensed trap by lifting up word and taking care not to spill any of the water. There may be water left in the unit end it needs to be removed carefully to prevent safety concerns. When your unit is lifted start removing the flexible pipe located on the outlet. Once this is done remove the located at the base of your condense trap. If there is any solid material located in the or the trap, clean it away.

Then remove the float so that you can clean it in the same fashion. You should be able to flush water through the condense trap in order to remove any remaining solid matter. Once this is done look for any debris in the outlet pipe , connected to the condensate drain. If you find any remove it and clean the outlet pipe as necessary. Once this is done reassemble and refit your condensed trap.
When you are refitting this, make sure that you achieve a watertight seal but do not apply excessive force. Finally, remove the siphon adapter from the flexible tubes and with a suitable container the heat exchanger needs to be flushed for as long as the flushing water becomes clear. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Inner Casing Sealing Panel replacement

Access to Switches, User Interface and 230v controls Interface Start by releasing the front of the controls fascia . Do this by carefully prising up the two retaining latches . Make sure that the front of the fascia does not swing down . It is loosely held in place by the electrical connections to your mains reset switch and your user interface. If you allow the front to swing down it can cause damage to these areas. Either remove the connections or make sure to support the fascia during this process.

When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Mains Reset Switch replacement

To replace the mains reset switch start by removing the switch retaining screw. Once this is done remove the switch from the housing. Finally, remove any electrical leads and replace the part as necessary. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Mains Reset Knob replacement

To replace the mains reset knob, start by removing the actuator. You can do this by springing back the retaining clips. Once this is done spring back the knob retaining clips and push the knob out of the back in accordance with the diagram pictured opposite these instructions. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

User Interface replacement

user interface

To replace the user interface start by removing the electrical plug. Once this is done remove the three screws which secure the user interface to the board. Please note that when you are replacing the user interface board you should refer to the instructions supplied with the replacement user interface board . When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Main PCB replacement

To replace the main PCB you must start by hinging down the control box. Remove the screws holding it in place and unhook the rear panel. Once this is done remove the electrical connections which connect to the PCB. Hold back the two PCB retaining clips so that you can easily withdraw the PCB. Once this is done make your replacement. When you are refitting the rear panel, make sure that the leads are not trapped. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Control Box replacement

When you are replacing the control box start by removing any relevant plugs and connectors in accordance with the wiring diagram. Once this is done remove the grommets and the leads and make sure that they do not hang loosely. After this, unthread your retaining strap. Then remove the control box by slowly drying it outward away from the retaining slots. Make your replacement as necessary. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

Fuse – Main PCB – Control Box replacement

To replace the fuse follow the steps for replacing the main PCB and control box. Please note that the fuse is located at the bottom right-hand side of the PCB. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.

230V Controls Interface replacement

To replace the controls interface start by disconnecting the electrical connection from the controls interface board. Also disconnect the electrical connection from the PCB. Once this is done remove the 230 V controls Interface retaining screw. Once this is done you can remove the controls interface board and make your replacement as necessary. When installing the replacement part, make sure it is an approved Glow Worm replacement part. After installation, replace all components in the opposite order of their removal and conduct any functionality or operational tests as necessary.