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Hi Everyone,
I've been struggling with this for a week or so now and after reading a few similar posts, I thought I would see if anyone could give me a little bit more advice. I apologise in advance as there is a little bit of a backstory to this.
In December our hot water started going hot/cold/hot/cold and the temperature readout on the boiler was rocketing up and down. I had Homecare cover through British Gas so after getting an engineer out they said the heat exchanger would need to be changed due to dirt in the system and I would be quoted for a powerflush, magnaclean the lot. A week or so later the engineer returned to change the heat exchanger (unfortunately I wasn't here so didn't see exactly what was done) and a note was left saying there was dirt in the system and would need a powerflush.
The British Gas experience was awful (not the first time) so I have promptly cancelled my Homecare package in favour of seeking a local plumber for a powerflush and any future repairs.
The hot water problem was resolved but we soon found that the central heating would not come on - The click would come from the receiver (Hive) but the boiler would not act on this call to heat, however I soon found that this was resolved by running the hot water which seemed to kick the boiler into providing central heating. This worked a few times but unfortunately is now working a lot less if at all...
When the boiler is in this state of providing hot water but not igniting for central heating there is a constant noise present which only changes when calling for hot water and then returns to a drone which I think is some sort of fan (tacho fan?). This is noise is present in all modes eg, Hot Water Only, Central Heating etc.. and only switches off when the boiler control is in the off position or if the "switching on the hot water" solution I mentioned earlier has worked.
I have taken it upon myself to try and resolve this issue as I have been unable to get a decent local plumber out as they all appear to booked up for a good while.
My first thought was the divertor valve actuator or valve itself. Manual operation of this valve (with the actuator off) makes no difference and for good measure I purchased a replacement actuator which has made no difference (I have since confirmed my old actuator is perfectly fine). I have also made sure there is no air in the system by bleeding all the radiators and the pressure is at its usual 1.5 bar.
I should probably add there are also no error codes or lockout conditions occuring.
My current line of thinking is that it's thermistor/ntc sensor of some kind as after a test an hour ago I noticed that when the boiler was powered back up and after running some hot water the temperature gauge rocketed up to around 70 which makes little sense as no water was being called and the central heating was off. My only logic behind this is that a temperature sensor is goosed making it think the boiler is crazy hot and not allowing the central heating to fire because of this although this is where I need a little as I can't find any evidence of this in the service manual...
Thanks a lot for reading this very long post and I appreciate any help anybody could give me.
UPDATE: Left the boiler off (on the controls not mains) to see if this helped. Turning it back on resulted in the droning noise coming back and the temperature flying up to 70 odd again. Turned hot water on/off a few times - Drone noise went, temperature read 51 and central heating could be ignited...
I've been struggling with this for a week or so now and after reading a few similar posts, I thought I would see if anyone could give me a little bit more advice. I apologise in advance as there is a little bit of a backstory to this.
In December our hot water started going hot/cold/hot/cold and the temperature readout on the boiler was rocketing up and down. I had Homecare cover through British Gas so after getting an engineer out they said the heat exchanger would need to be changed due to dirt in the system and I would be quoted for a powerflush, magnaclean the lot. A week or so later the engineer returned to change the heat exchanger (unfortunately I wasn't here so didn't see exactly what was done) and a note was left saying there was dirt in the system and would need a powerflush.
The British Gas experience was awful (not the first time) so I have promptly cancelled my Homecare package in favour of seeking a local plumber for a powerflush and any future repairs.
The hot water problem was resolved but we soon found that the central heating would not come on - The click would come from the receiver (Hive) but the boiler would not act on this call to heat, however I soon found that this was resolved by running the hot water which seemed to kick the boiler into providing central heating. This worked a few times but unfortunately is now working a lot less if at all...
When the boiler is in this state of providing hot water but not igniting for central heating there is a constant noise present which only changes when calling for hot water and then returns to a drone which I think is some sort of fan (tacho fan?). This is noise is present in all modes eg, Hot Water Only, Central Heating etc.. and only switches off when the boiler control is in the off position or if the "switching on the hot water" solution I mentioned earlier has worked.
I have taken it upon myself to try and resolve this issue as I have been unable to get a decent local plumber out as they all appear to booked up for a good while.
My first thought was the divertor valve actuator or valve itself. Manual operation of this valve (with the actuator off) makes no difference and for good measure I purchased a replacement actuator which has made no difference (I have since confirmed my old actuator is perfectly fine). I have also made sure there is no air in the system by bleeding all the radiators and the pressure is at its usual 1.5 bar.
I should probably add there are also no error codes or lockout conditions occuring.
My current line of thinking is that it's thermistor/ntc sensor of some kind as after a test an hour ago I noticed that when the boiler was powered back up and after running some hot water the temperature gauge rocketed up to around 70 which makes little sense as no water was being called and the central heating was off. My only logic behind this is that a temperature sensor is goosed making it think the boiler is crazy hot and not allowing the central heating to fire because of this although this is where I need a little as I can't find any evidence of this in the service manual...
Thanks a lot for reading this very long post and I appreciate any help anybody could give me.
UPDATE: Left the boiler off (on the controls not mains) to see if this helped. Turning it back on resulted in the droning noise coming back and the temperature flying up to 70 odd again. Turned hot water on/off a few times - Drone noise went, temperature read 51 and central heating could be ignited...
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