18 Oct 2007Hi Mathew,
Are you sitting comfortably........................... Then I'll begin.
Having read about your experiences I decided to give my repair a go. The task was a bit of a marathon though. Stripping down went well enough, though I almost fell at the first hurdle. When I opened the drain taps, nothing happened. I ended up taking the white plastic centre parts of the tap out completely, and still no water. In the end, I stuck a small screwdriver in to the centre of the tap body, and cleared out much black crud, and hence the system drained. The rest of the parts came out without issue.
Putting back together was a different story all together. The diverter valve itself went in OK, but the "bent pin" clip holding in the bypass pipe just would not go in. After a number of removals of the diverter valve to check the hole was OK, and the O-ring seated properly, I eventually decided the only way to find out what was happening was to take the bypass pipe out all together. Out of the boiler housing, the pipe fitted so easily it was scary.
Now all I had to do was get the old O-ring out of the connection at the right hand side, which I thought would take ages, but in fact came out quite easily with tweezers. So I put the diverter valve back in, put the bypass pipe back in, and still the clip would not fit. In the end, I had to lift the right hand end of the bypass pipe from it's housing to allow the left hand end to be fitted first. Now it located and the pins went in first time - the right hand end also went in easily. Nowhere in the service manual is this tip documented, but really it cost me 2 hours of trying because I thought if I took the right hand end out I wouldn't be able to clean the joint and replace the O-ring without removing even more parts from the boiler.Obviously, I hadn't been able to clean out the seating faces of the hole in the pressure valve body, but the new O-ring seems to have sealed anyway.
The heat exchanger went in easily - it was the last easy part of the job.
The first attempt at putting the filling loop in place seemed to go OK, but pushing the unit rightwards to locate into the inlet valve was very stiff. The left hand end located up OK, and the water was turned on. The reason for the stiffness became apparent, the little O-ring on the right hand end had caught somehow, and broken, with the obvious result once water was applied.
So the water was turned off and what was left in the boiler drained again. The filling loop removed, O-ring replaced, and a second attempt made. This time the right hand end seemed to locate more easily. The left hand end screwed down, and the boiler filled. A few drips from the left hand end of the filling loop were stopped by tightening the screws, and all looked good. But the pressure didn't come up, and the boiler wouldn't turn on. Double flashing reds suggested no water pressure, but water had definitely flowed into the boiler, and the hot water taps would run, but obviously not heat the water. After much head scratching, and repeated turnings of the filling key - I eventually tried turning the little grey knob - water flowed into the boiler, and straight out of the left hand end of the filling loop mating surface!!! In the blind panic of having water all over the place, I dived underneath to turn off the valves again, and disloged the front panel from it's hinged down position. It fell floorwards, but I caught it before it pulled the pressure gauge pipe out, which was very fortunate.
Stripping the filling loop out again, I found the metal bracket hadn't located over the mating surface properly. Screwing the filling loop down had located it against the support bracket, but not fully against the actual mating surface on the diverter valve. This was corrected, the loop refitted, and water turned on again. This time, no immediate signs of serious leaks. A bit of drying up was required before I could turn the electrics back on, but eventually the switch was thrown.
Well, the pump would run, but still no heat. I could hear the igniter ticking, but no flames. I couldn't tell if this was because the gas wasn't being turned on, or there was no spark at the igniters. The flashing lights indicated an electrical sensor fault, and in investigating this the broken cables were found - remember I said the front panel had fallen.......
Now - I should be able to do electronics - but all the cables listed in the manual, and visible on your photos seemed to be in place. In fact it was the igniter cables that had pulled out (snapped actually!). So I had to get to the controller board and re-attach these cables, but where and to what I couldn't tell at this point.
I should probably point out that to get the controller board out, you have to remove the 3 control knobs. The manual does say "carefully", but they are very stiff. The hot water control knob came out easily enough, they are just a simple knob with about a 2.5 inch shaft. The central heating control was much tighter, but came eventually. The On/Off just didn't want to move. A heave with a pair of pliers brought it out though - but the shaft was only an inch long, and had an ominously jagged end. So, the on-off controll knob was broken, a length of it's shaft was still in the panel (so I couldn't use one of the water control ones in its place) and of course, the swich was set to the off position.
I'd really had enough of the job by this stage, so I decided to put this control knob issue off until later, and deal with the problem I had started to fix, i.e the reconnection of the electrode wires. I managed to get the controller board lifted, but the polarity of the connectors for these two wires is not listed in the manual. I took an educated guess, pressumed that polarity would not be an issue to the electrodes of the igniter probes and with heart in mouth took the soldering iron to the loose wires.
Now it really was anybody's guess if I'd soldered the igniter wires the correct way round (if they were polarised), so I could be about to send a spark to the gas with no reference to any logic. But I still couldn't try it out, because of the broken control knob. However, on close inspection, the shaft is basically round, with a flat edge to locate and key into the switch body, and there was at least a cm of shaft with the flat here - so I stuffed it in and hoped there would be enough to engage. And, low and behold there was - turning the knob did feel to be driving the switch.
Fortunately at this point, there was no-one else in the house to get blown up with me, so I threw the power on and turned the switch anyway. Still being alive, and the house still having all it's windows, I even braved turning on a tap - water flowed, and it was HOT!!!!. I set the timer up, the pump whirred, and the radiators started radiating. At this point, the cat wandered in, curled up infront of the kitchen radiator, and looked across with an "about time too" look on it's face. It soon had a "what was that for" look on it's face as my size 9 connected with an appropriate part of it's anatomy.
Hey - I now have a warm house, and a hot shower. And it's all thanks to you. I'm sure I'll forget, and eventually forgive you for making it look oh so easy.
Seriously, thankyou. I'm really happy to have been able to do this myself. I really hate paying others to do stuff I can do myself, and especially when the so called regulations say you have to use a "professional" despite the apparent knowledge and ability of some of these pros being suspect to say the least (that may sound rich coming from me but I'm not claiming to be a pro - this job was my first boiler repair). It seems that in part the primary intent of some of these regulations may well be to protect the commercial interests of the industry. Anyway, rant over and thanks again!