MilesA Posted December 22, 2022 Report Share Posted December 22, 2022 11 hours ago, RobH said: That is a very good point. We are all assuming the fault is in the boiler but that may not be the case. Boilers are part of a system that usually includes a timer (programmer) and thermostats. If the boiler heats a hot water cylinder as well as radiators, there are usually one or more motorised zone valves which 'steer' where the water goes. The room and tank thermostats operate the appropriate valves and the valves in turn have switches which send power to the boiler only when the valve has reached full travel. The boiler and water circulation pump cannot operate until they receive power from the motorised valve. Do you know whether the water circulation pump is operating? If it is the zone valves (if present) are probably working OK but if the pump doesn't run either then maybe the fault is with a valve and not the boiler. Just had a valve fail on our system. We have two valves: one to direct water to the hot water tank and one to direct water to the heating system. A couple of galvanised steel boxes plumbed into the pipe work and wired in. Ours each have a small lever emerging from the top of each box so one can manually override. An easy way of checking whether the valve is working. Miles Quote Link to post Share on other sites
Charlie D Posted December 22, 2022 Report Share Posted December 22, 2022 11 hours ago, RobH said: Do you know whether the water circulation pump is operating? The circulation pump will only be needed for the radiators surely. (As far as I know it is not needed for the hot water supply.) Just by turning the hot water tap on should fire up the boiler without the need to be looking at the heating logic, so even if the zone valves were faulty, the fan would still work and the boiler would fire, and supply hot water out of the tap. (I think…) Please can you confirm that you don't get hot water when a tap is turned on. Quote Link to post Share on other sites
RobH Posted December 22, 2022 Report Share Posted December 22, 2022 (edited) 39 minutes ago, Charlie D said: The circulation pump will only be needed for the radiators surely. No - in systems with a storage tank it is required for both hot water and rads Charlie . The heat-exchanger coil in the tank is just another radiator* really. You are thinking of a Combi boiler which this isn't. (* silly name actually - they mainly heat by convection not by radiation) Edited December 22, 2022 by RobH Quote Link to post Share on other sites
BlueTR3A-5EKT Posted December 22, 2022 Report Share Posted December 22, 2022 This just points to fan or pressure switch. https://www.miketheboilerman.com/potterton-kingfisher.html Kingfisher MF: The Kingfisher MF is a totally different boiler inside, despite being a floor standing boiler looking broadly like the older Kingfisher. The MF is significantly more fuel-efficient due to having fully automatic electronic ignition, no permanent pilot light, electronic flame detection and a fan-powered flue (even the open flue versions with a vertical chimney) all operated by a central electronic control board. Being a non-condensing boiler however, the Kingfisher MF was discontinued when condensing boilers became mandatory in 2005. 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 etc. The Kingfisher MF has overheat protection so should the heat exchanger overheat, the boiler ‘locks out’. ‘Locking out’ means the boiler illuminates a red ‘lockout light’ and turns itself off, requiring the user to reset boiler by pressing the ‘Reset’ button once the boiler had cooled for a while. The ‘Lockout’ light would be better labeled “overheat” in my personal opinion, as this is what it actually means. There are three common causes of overheating in the heat exchanger, leading to locking out: 1) An external fault, nothing to do with the boiler. No bypass circuit fitted by the installer. The boiler runs the pump for a few minutes to distribute residual heat after the burners shut down, and if the heating system installer does not ensure there is a water circuit available for this water flow after shut-down, the residual heat will not be distributed and the boiler will occasionally (or regularly) lock out. 2) The pump over-run function on the boiler failing, so residual heat in the heat exchanger after boiler shut-down no longer gets distributed. 3) Dirty system water. Corrosion deposits getting picked up from inside radiators etc and being carried into the heat exchanger and deposited there, where they stay for ever and prevent heat in the cast iron passing through into the water. There is one further possible reason for locking out… On the vertical flue (open flue) versions, fresh air is drawn from the room into the top of the boiler to dilute and cool the hot flue gasses rising up the chimney. Should the chimney flue get blocked, those potentially dangerous hot flue gasses can spill out through the air intake into the room containing the boiler as they can no longer pass up the chimney flue. To guard against this spillage there is a spillage thermostat (often referred to as a “TTB sensor”) mounted in the air intake which trips when spillage occurs, also putting the boiler into ‘Lockout’. So if your Kingfisher is the vertical chimney flue version and locking out, it is possible there is a fault with the flue rather than it overheating. Common faults and fixes: 1) Pilot flame failure. This boiler has a pilot light which only runs when the boiler is ON. It shuts down when there is no demand for heat. When there is demand for heat, the pilot flame lights first then about one second later the pilot lights the main burner. This misleads owners and technicians into not realising there is a separate pilot light at all. I’d go as far as to say most Kingfisher MF failures revolve around the pilot failing to light and the possible reasons for this deserve a sub-section all of their own. 1a) If the pilot flame is failing to light, a common cause is a blocked pilot injector. The burner assembly and pilot assembly are at floor level and on open flue versions terribly prone to contamination with dirt and dust, although blockage can occur on both open and balanced flue versions. The injector can sometimes be cleared with a piece of 5A fuse wire but take care, it is made from soft aluminium. Better to replace with a brand new injector. 1b) If the injector is not blocked then either there is no gas supply to the pilot or there is no spark. Or both. When neither gas nor spark are present this usually indicates flue fan failure or air pressure switch (APS) failure. (The APS detects the fan running before allowing gas and spark to the pilot.) 1c) If there is gas but no spark, either the PCB is failing to produce a spark or the ignition lead is broken. 1d) If there is a spark but no gas, check for continuity across the gas valve pilot solenoid. The value should be around 2,000 Ohms. If you get this correct value check for 175Vdc on the terminals (beware this high DC voltage is DANGEROUS). No voltage suggests PCB failure, DC voltage present suggests mechanical failure inside the gas valve. 2) If there is a pilot flame present but no progression to ignition of the main burner, then the gas valve main burner solenoid is not opening. Apply the same checks to the main burner solenoid as to the pilot in 1d) above. One perverse failure to mention is that on a boiler with PCB failure, the failure is sometimes caused by a gas valve fault. There is a ‘fusible resistor’ on the PCB that fuses when the gas valve fails meaning the gas valve failure looks to the engineer like a failed PCB. Just plugging in an expensive new PCB without replacing the gas valve solenoids for continuity first can result in the new PCB being damaged instead of the boiler starting to work. Beware! If you would like me to repair your Potterton Kingfisher, contact me on my mobile 07866 766364 Post script: Clearances and access: All boilers require good front access for servicing and repair. Boilers fitted into the corners of kitchens and surrounded with kitchen units can be a particular problem in this respect. Access from the side makes a boiler far more difficult and time-consuming to work on, if it is possible at all. The manuals for the earlier models of Kingfisher boiler state 61cm (two feet) of clear space is needed directly in front of the boiler, which in practice might be adequate, but only just. Three feet of space is far better. The manual for the MF models states 25cm (10 inches) which is quite impractical. I shall need an absolute minimum of two feet of clear floor space directly in front of any model of Kingfisher boiler to repair it, preferably three feet, and I will check this with you on the phone before accepting a booking to visit. (If I remember!) Diagram from the manual showing the MF boiler controls, including the lockout light and the reset button If you like what I write, please Buy me a coffee. Thank you kindly! Quote Link to post Share on other sites
Charlie D Posted December 22, 2022 Report Share Posted December 22, 2022 12 minutes ago, RobH said: You are thinking of a Combi boiler which this isn't. Ahhh.. Yes, that is what I was thinking. Does that not mean though that it could also be the circulation pump that is faulty? Quote Link to post Share on other sites
RobH Posted December 22, 2022 Report Share Posted December 22, 2022 (edited) If the circulation pump goes faulty the boiler quickly overheats and the overheat thermostat opens, cutting off power. Richard has already checked that thermostat and the reset switch so I guess the pump is OK. Edited December 22, 2022 by RobH Quote Link to post Share on other sites
Richmac Posted December 22, 2022 Author Report Share Posted December 22, 2022 20 hours ago, Charlie D said: OK so you CAN use a multimeter . What I am about to say is done entirely at your own risk. Make sure the power to the entire boiler is OFF. Remove the two push on connectors from the fan motor. Set your multimeter to measure AC 250 volts (Or more). Push the multimeter probes into the purple connectors from the fan. (If you are at all concerned, wrap these joints in insulation tape.) Let go of everything from your hands, but make sure you can read the meter. Switch the power back on. See what the reading on the meter says, and let us know what the reading is. Charlie. Hi Charlie no I can't use a multimeter I just put it on a random setting that when I touch the prongs together changes the reading. My logic is if it changes touching the prongs and does the same thing on the item I'm trying to test then there is a circuit. No talent involved!! I think I will be brave enough to try your suggestion and report back. Quote Link to post Share on other sites
Gordon Bayley Posted December 22, 2022 Report Share Posted December 22, 2022 Just seen this , there is a reset on the boiler front and an over heat stat on the pipework, does the pump run? have you got power to the air pressure switch? you can do most tests with a neon screwdriver (circuit tester), An electrician could fault find he does not have to be Gas Safe because he's not touching the gas or the flue. good luck, but be safe. Quote Link to post Share on other sites
roy53 Posted December 22, 2022 Report Share Posted December 22, 2022 Just had this on a BAXI. All indication was circuit board or flow. It was flow as the pump was clogged with rust. Sounded ok as running but no flow. Saftey cut out clicked in New pump all ok Quote Link to post Share on other sites
Richmac Posted December 22, 2022 Author Report Share Posted December 22, 2022 23 hours ago, Charlie D said: OK so you CAN use a multimeter . What I am about to say is done entirely at your own risk. Make sure the power to the entire boiler is OFF. Remove the two push on connectors from the fan motor. Set your multimeter to measure AC 250 volts (Or more). Push the multimeter probes into the purple connectors from the fan. (If you are at all concerned, wrap these joints in insulation tape.) Let go of everything from your hands, but make sure you can read the meter. Switch the power back on. See what the reading on the meter says, and let us know what the reading is. Charlie. Quote Link to post Share on other sites
Richmac Posted December 22, 2022 Author Report Share Posted December 22, 2022 2 hours ago, Gordon Bayley said: Just seen this , there is a reset on the boiler front and an over heat stat on the pipework, does the pump run? have you got power to the air pressure switch? you can do most tests with a neon screwdriver (circuit tester), An electrician could fault find he does not have to be Gas Safe because he's not touching the gas or the flue. good luck, but be safe. Pump runs Gordon but not sure how to test the pressure switch Quote Link to post Share on other sites
Charlie D Posted December 22, 2022 Report Share Posted December 22, 2022 Wooopy -Doooo !!! Not sure why it says 245volts instead of 230, but it does seem to show that you have power to the fan but no fan turning. As before, I await Robs answer, but it does look like a faulty fan. Charlie. Quote Link to post Share on other sites
Richmac Posted December 22, 2022 Author Report Share Posted December 22, 2022 10 hours ago, BlueTR3A-5EKT said: This just points to fan or pressure switch. https://www.miketheboilerman.com/potterton-kingfisher.html Kingfisher MF: The Kingfisher MF is a totally different boiler inside, despite being a floor standing boiler looking broadly like the older Kingfisher. The MF is significantly more fuel-efficient due to having fully automatic electronic ignition, no permanent pilot light, electronic flame detection and a fan-powered flue (even the open flue versions with a vertical chimney) all operated by a central electronic control board. Being a non-condensing boiler however, the Kingfisher MF was discontinued when condensing boilers became mandatory in 2005. 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 etc. The Kingfisher MF has overheat protection so should the heat exchanger overheat, the boiler ‘locks out’. ‘Locking out’ means the boiler illuminates a red ‘lockout light’ and turns itself off, requiring the user to reset boiler by pressing the ‘Reset’ button once the boiler had cooled for a while. The ‘Lockout’ light would be better labeled “overheat” in my personal opinion, as this is what it actually means. There are three common causes of overheating in the heat exchanger, leading to locking out: 1) An external fault, nothing to do with the boiler. No bypass circuit fitted by the installer. The boiler runs the pump for a few minutes to distribute residual heat after the burners shut down, and if the heating system installer does not ensure there is a water circuit available for this water flow after shut-down, the residual heat will not be distributed and the boiler will occasionally (or regularly) lock out. 2) The pump over-run function on the boiler failing, so residual heat in the heat exchanger after boiler shut-down no longer gets distributed. 3) Dirty system water. Corrosion deposits getting picked up from inside radiators etc and being carried into the heat exchanger and deposited there, where they stay for ever and prevent heat in the cast iron passing through into the water. There is one further possible reason for locking out… On the vertical flue (open flue) versions, fresh air is drawn from the room into the top of the boiler to dilute and cool the hot flue gasses rising up the chimney. Should the chimney flue get blocked, those potentially dangerous hot flue gasses can spill out through the air intake into the room containing the boiler as they can no longer pass up the chimney flue. To guard against this spillage there is a spillage thermostat (often referred to as a “TTB sensor”) mounted in the air intake which trips when spillage occurs, also putting the boiler into ‘Lockout’. So if your Kingfisher is the vertical chimney flue version and locking out, it is possible there is a fault with the flue rather than it overheating. Common faults and fixes: 1) Pilot flame failure. This boiler has a pilot light which only runs when the boiler is ON. It shuts down when there is no demand for heat. When there is demand for heat, the pilot flame lights first then about one second later the pilot lights the main burner. This misleads owners and technicians into not realising there is a separate pilot light at all. I’d go as far as to say most Kingfisher MF failures revolve around the pilot failing to light and the possible reasons for this deserve a sub-section all of their own. 1a) If the pilot flame is failing to light, a common cause is a blocked pilot injector. The burner assembly and pilot assembly are at floor level and on open flue versions terribly prone to contamination with dirt and dust, although blockage can occur on both open and balanced flue versions. The injector can sometimes be cleared with a piece of 5A fuse wire but take care, it is made from soft aluminium. Better to replace with a brand new injector. 1b) If the injector is not blocked then either there is no gas supply to the pilot or there is no spark. Or both. When neither gas nor spark are present this usually indicates flue fan failure or air pressure switch (APS) failure. (The APS detects the fan running before allowing gas and spark to the pilot.) 1c) If there is gas but no spark, either the PCB is failing to produce a spark or the ignition lead is broken. 1d) If there is a spark but no gas, check for continuity across the gas valve pilot solenoid. The value should be around 2,000 Ohms. If you get this correct value check for 175Vdc on the terminals (beware this high DC voltage is DANGEROUS). No voltage suggests PCB failure, DC voltage present suggests mechanical failure inside the gas valve. 2) If there is a pilot flame present but no progression to ignition of the main burner, then the gas valve main burner solenoid is not opening. Apply the same checks to the main burner solenoid as to the pilot in 1d) above. One perverse failure to mention is that on a boiler with PCB failure, the failure is sometimes caused by a gas valve fault. There is a ‘fusible resistor’ on the PCB that fuses when the gas valve fails meaning the gas valve failure looks to the engineer like a failed PCB. Just plugging in an expensive new PCB without replacing the gas valve solenoids for continuity first can result in the new PCB being damaged instead of the boiler starting to work. Beware! If you would like me to repair your Potterton Kingfisher, contact me on my mobile 07866 766364 Post script: Clearances and access: All boilers require good front access for servicing and repair. Boilers fitted into the corners of kitchens and surrounded with kitchen units can be a particular problem in this respect. Access from the side makes a boiler far more difficult and time-consuming to work on, if it is possible at all. The manuals for the earlier models of Kingfisher boiler state 61cm (two feet) of clear space is needed directly in front of the boiler, which in practice might be adequate, but only just. Three feet of space is far better. The manual for the MF models states 25cm (10 inches) which is quite impractical. I shall need an absolute minimum of two feet of clear floor space directly in front of any model of Kingfisher boiler to repair it, preferably three feet, and I will check this with you on the phone before accepting a booking to visit. (If I remember!) Diagram from the manual showing the MF boiler controls, including the lockout light and the reset button If you like what I write, please Buy me a coffee. Thank you kindly! I saw this thank you but my manual would suggest a PCB failure? If the guy was nearer I would have given him a call Quote Link to post Share on other sites
RobH Posted December 22, 2022 Report Share Posted December 22, 2022 (edited) Looking more and more like a duff fan motor then, since the PCB is obviously supplying the required voltage, though that is measured without a load. To be 100% sure you could try connecting the fan direct to the mains as I described above. (The pressure switch can't operate unless the fan is running so it isn't that.) For the record 245V is normal for the mains voltage - it is nominally 230V and has a tolerance of +10%, -6% so should be between 216 and 253 volts. Edited December 22, 2022 by RobH Quote Link to post Share on other sites
Richmac Posted December 22, 2022 Author Report Share Posted December 22, 2022 On 12/21/2022 at 8:23 PM, Charlie D said: OK so you CAN use a multimeter . What I am about to say is done entirely at your own risk. Make sure the power to the entire boiler is OFF. Remove the two push on connectors from the fan motor. Set your multimeter to measure AC 250 volts (Or more). Push the multimeter probes into the purple connectors from the fan. (If you are at all concerned, wrap these joints in insulation tape.) Let go of everything from your hands, but make sure you can read the meter. Switch the power back on. See what the reading on the meter says, and let us know what the reading is. Charlie. Quote Link to post Share on other sites
Richmac Posted December 22, 2022 Author Report Share Posted December 22, 2022 16 minutes ago, RobH said: Looking more and more like a duff fan motor then, since the PCB is obviously supplying the required voltage, though that is measured without a load. To be 100% sure you could try connecting the fan direct to the mains as I described above. (The pressure switch can't operate unless the fan is running so it isn't that.) For the record 245V is normal for the mains voltage - it is nominally 230V and has a tolerance of +10%, -6% so should be between 216 and 253 volts. Thanks Rob and Charlie and others for your help. I'm not comfortable plugging the fan directly to the mains so I'll do a search for a replacement fan Quote Link to post Share on other sites
Gordon Bayley Posted December 23, 2022 Report Share Posted December 23, 2022 12 hours ago, Richmac said: Yes it looks like its the fan. Quote Link to post Share on other sites
Richmac Posted December 23, 2022 Author Report Share Posted December 23, 2022 However why doesn't mkmicks trick of blowing into the pipe to trick the diaphragm into thinking the fan is turning work? Quote Link to post Share on other sites
Charlie D Posted December 23, 2022 Report Share Posted December 23, 2022 It does all seem a bit mysterious in a way. The mains voltage to the fan and the fan not turning indicates the fan is faulty. Blowing (Sucking) into the pipe should fool the logic board into thinking that the fan IS working. (Can you hear a click when you blow/suck. That does not mean the pressure switch is definitely working electric wise, just pneumatic wise.) BUT… The fan would have to turn a bit initially before the required pressure/vacuum would appear in the pipe. The fan is not turning at all, even though it seems to have power. This could indicate the logic board is a at fault by not giving power to the fan. (But we DO have power to the fan...) You would expect that if the logic board was OK and the pressure switch was OK then blowing (Sucking) the pipe would make the boiler burst into life. I take it that does not happen. This points to either the logic board at fault, or the pressure switch at fault. BUT if there is voltage to the fan, then why does it not work? (We seem to be going around in circles a bit.) It seems a shame to get a new fan if the one you have is OK. Maybe a safer way to do Rob’s test (Putting mains directly to the fan.) would be to take it out and wire it up on a bench. (Hold the fan in a vice.) The idea of getting a local electrician to look at it and go through the flow chart tests seems a good idea, but could you find one this week? Not sure what else to suggest. Charlie. Quote Link to post Share on other sites
Charlie D Posted December 23, 2022 Report Share Posted December 23, 2022 Just another thought. (Clutching at straws.) Maybe... The fan has to operate the pressure switch within a certain number of seconds once the demand for heat is asked. If so, by the time you start blowing(sucking) the pipe it may have timed out. Quote Link to post Share on other sites
brian -r Posted December 23, 2022 Report Share Posted December 23, 2022 Following a delay in lawyers completing the purchase of our new home ,we had to rent for a while . Sods law the boiler would not light ,the landlord called British Gas and eventually an engineer turned up. His conclusion was that the fan had stuck so removed it freed it off job done, could this be a similar issue. just a thought Bri Quote Link to post Share on other sites
RobH Posted December 23, 2022 Report Share Posted December 23, 2022 1 hour ago, Richmac said: However why doesn't mkmicks trick of blowing into the pipe to trick the diaphragm into thinking the fan is turning work? What are the chances of two faults at the same time? Unlikely perhaps? Best to fix the fault you definitely know about first - the fan doesn't run even though it seems to have power. If the boiler still doesn't work when you have cured that, you can then look for a second fault but the odds are you won't have to. Quote Link to post Share on other sites
250 Posted December 23, 2022 Report Share Posted December 23, 2022 Just thought on working on old a/c plant years ago, looks like there is power to the fan motor so with the power off can you see the fan with any covers off? If so is it stuck or does it turn freely? and if it does turn and your confident enough power the unit up and lightly flick the fan in the normal rotation with a pencil or something similar does it run if so could be a capacitor fault although might not be prudent on newer boiler type fan motor. Mark. Quote Link to post Share on other sites
RobH Posted December 23, 2022 Report Share Posted December 23, 2022 15 minutes ago, 250 said: if so could be a capacitor fault It is a shaded-pole motor so has no capacitor Mark. Quote Link to post Share on other sites
Richmac Posted December 23, 2022 Author Report Share Posted December 23, 2022 Well as an update a couple of days ago I was convinced enough that the PCB at fault that I ordered a reconditioned one from ebay with an expected delivery date of 28th December. However low and behold it turned up today. Yesterday I was sufficiently convinced that the fan was at fault but decided that as I now had a replacement PCB board I would fit it anyhow and low and behold the boiler has burst back into life and I now have fully working heating system. So I want to thank all of you on here for contributing, not just for your knowledge but your posts also provided me with the motivation to continue trying. I also wanted to say that I'm sure there are some out there who were thinking I'm out of my tiny mind to be messing with something I have no knowledge of and without being Part P or Gas Safe registered. I would say I always made sure there was no power to the boiler before messing and was fully aware I may do more harm than good to my boiler. I will also fit a CO Detector, although I haven't touched any gas joints, and will get the boiler fully serviced in the new year. This was always about getting me through the holiday period but it has given me an a learning curve on how boilers work, how to use a multi-meter and a sense of achievement at having fixed something myself that I also get working on the TR So thank you all again I don't think I would have achieved it without your help so I wish you all a merry and warm Christmas Regards Richard Quote Link to post Share on other sites
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