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Potterton Kingfisher and Kingfisher 2 gas boiler (not Kingfisher MF)


If your early version Potterton Kingfisher (i.e. not the later Kingfisher MF) won’t work, it can probably still be fixed despite its age. They are a really simple, basic and reliable boiler from the 1980s with very little to go wrong but if yours won’t light, you’re very unlucky! (None of these comments apply to the Kingfisher MF by the way. The Kingfisher MF is far more complex and works in a completely different way.) If you’d like me to visit to fix your Potterton Kingfisher, get in touch. Call, text or WhatApp me on 07866 766364.




What to check if your Potterton Kingfisher stops working:


1) The pilot light. This is the No 1 fault on these. Pull the front off the boiler and look inside to see if the pilot flame is present. If no flame, this will be why it doesn’t work and it needs lighting. There are instructions on the back of the front panel you just removed. I’ll record a video of how to light one next time I work on a Kingfisher, but in the meantime here is a helpful video posted on YouTube by a chap called Christopher Mahon.


2) Check the heating is set to ON at the programmer or time switch.


3) Check the room thermostat is at a ‘high’ setting.


4) Check this white temperature control knob in the boiler is set to a high setting, and not set to OFF. In this screenshot from the video it is set to ‘4’.




4) If your pilot flame was out and you successfully re-lit it, check you remembered to turn the the black control knob the final quarter turn to the ‘flame’ position. This is easy to forget, I know this from experience :) The black control knob  can be clearly seen in the video, set to the ‘flame’ position. 


If you’ve done all the above with no joy, or if the pilot flame keeps going out, you’ll need a visit from a boiler technician. Call me if you wish on 07866 766364. I’m based in Reading, Berkshire and am happy to travel. You can also text or WhatsApp me on that number. 



Potterton Kingfisher description and history:


The Potterton Kingfisher boiler started life as a simple and basic floor standing boiler. Despite most boilers being wall-hung by the 1980s/1990s there was still a rump of demand for an old style boiler standing on the floor to connect into a vertical chimney, or have that newfangled type of flue which passes horizontally to outside through the wall. 


The Kingfisher 2 was the next model launched but was just a facelift version and virtually identical inside, and technically. Both very basic boilers. A cast iron heat exchanger is heated by a gas burner in the base of the boiler. The gas is lit by a permanent pilot light, and turned on and off to control the boiler temperature by a thermostat with a sensor inside the heat exchanger. The ‘multi-function gas valve’ supervises the pilot flame using a thermocouple, turns the gas on and off to the main burner, and regulates the gas pressure to the burner. The gas pressure is adjustable to allow the heat output of the boiler to be set to suit the heat load connected to the boiler. A really basic, ultra-reliable and easy-to-maintain boiler. Cherish yours if you have one!


When regulations preventing installation of permanent pilot light boilers came along, Potterton launched the “Kingfisher MF” in response for the same market. Still a floor standing boiler but now totally different inside, with electronic ignition and fan-powered flue, and a printed circuit board to control everything and provide flame monitoring. FAR less reliable and a major step backwards in my personal opinion, but there we are, the politicians insist we now use these marginally more fuel-efficient but hugely more complex boilers now. This suits me fine as mending them has turned into a career for me!


So we have two completely different boilers both called Kingfisher, and each has it’s own set of faults and common breakdowns. As follows:



Kingfisher and Kingfisher 2:



Thermocouple failure. 


This is the weakness in all ‘Old Skool’ boilers with a permanent pilot light. The thermocouple is the safety device that turns the gas OFF if the flame goes out. The Thermocouple tip is heated by the pilot flame, the heat creates an electric current which operates an electro-magnetic valve which keeps the gas ON. If the pilot flame goes out for any reason, the thermocouple cools, the electrical current stops and the thermo-electric valve springs closed, shutting off the gas. This also happens when the thermocouple fails, and the user is unable to make the pilot flame stay alight as there is no electrical current. A new thermocouple is needed, which is quick and easy to fit. 



Gas valve failure:


The thermoelectric valve in the gas valve is prone to failure resulting in identical symptoms to thermocouple failure above. A new gas valve is required. There are two types fitted to Kingfishers. One type is still available new and the other discontinued. If yours is the discontinued type the only option is to find a seller with some old stock or fit a second hand gas valve. Or replace the boiler, obviously.



Thermostat failure:


The temperature control knob is attached to the variable temperature thermostat spindle. This thermostat senses the temperature inside the heat exchanger and occasionally loses its calibration. A new thermostat is probably still available. Quite a rare failure though, and I haven’t needed to replace a thermostat on a Kingfisher for many years.





This is where the boiler pops and bangs as it heats up, making a noise like an electric kettle approaching boiling. The usual cause is corrosion contamination inside the heat exchanger. Not an important problem and many users elect to just live with it and ignore it. The corrosion can sometimes be removed by power flushing, or ‘boiler quietening’ chemicals can be added to the circulating water. Results are variable and no guarantees of a fix for kettling can be given. 


These are bout the only problems a basic Kingfisher suffers from. If you have one, I suggest you keep it!





Kingfisher MF: 


This boiler suffers from all the same failures as most fan-flued non-condensing boilers. Fan failure, air pressure switch failure, PCB failure, gas valve failure. I shall expand on these later and just publish this page as it is for now. 


One perverse failure to mention is that on a boiler with PCB failure, the failure is sometimes caused by a gas valve fault. Just fitting a new PCB results in the gas valve fault destroying the new PCB too, in which case both components need replacing together. Beware!





If you would like me to repair your Potterton Kingfisher, contact me on my mobile 07866 766364

Potterton Kingfisher temperature control knob, set to '4'.
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Copyright Michael Bryant 2019

Site first published 16th January 2004

Last updated 11th May 2019


Gas Safe Register 197499, CIPHE registration number 56207

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