Another little problem with utilities here at home. My ten year old boiler started leaking, fortunately it’s in the garage so not really the end of the world but still not a good thing. So my journey began slowly trying to work out what the issue was. Dripping water from the condense pump box was the cause. Picture of removed problem child below. However before forking out £320+ for a replacement i did some debugging to see if I could avoid that cost. Clearly you need to be a GasSafe registered person to go anywhere near your boiler, just for info this post.
So the box was leaking out the top and implied integral pump was not working. Good chat here about similar problems https://community.screwfix.com/threads/worcester-bosch-440cdi-condensate-pump-problem.257931/ I can add a little more info on my situation and some things I learnt. So I removed the pump from it’s location in the boiler to the front so I could watch it in action a little more. easily.
Good video here of how to get this far. https://www.youtube.com/watch?v=9oRVKY946z8
When the boiler powers up it appears to cycle the pump 3 to 4 times (always turn the power off when you are working on electrical appliances, especially damp boilers. ) This is great info, if it clears the water in the reservoir you know the pump works and the pipe is not blocked. Prior to this I ordered a new none return nozzle for £1 and fitted this. I think mine was on it’s way out anyway. However that didn’t fix the issue. After the initial pump outs filling the tank with water didn’t trigger a new pump out and hence my leak. Something a side here, there are two leds on the bottom of the tank. The lower one was solid green and the top was flashing green. Not clear from manual what that meant (broken , I suspect knowing what I know now!) The new unit has two solid green leds when working correctly
So pump works it must be the magnet float switch that has failed (last idea). Unfortunately this is in a sealed part of the box and from a couple of posts on the web there are no serviceable parts inside. So at this point I bought a new unit (WORCESTER 8716118488 CONDENSATION PUMP). While awaiting the new part I switched the boiler on and off every hour of use to clear the reservoir, not sure this is a great idea to keep power cycling the appliance but it does limit the amount of leaking water if you have to use the boiler. Of course you can siphon off the water manually (note this isn’t pure water but condense that I suspect will be fairly acidic, wear gloves , keep off skin ETC ETC)
Fitting of the unit is straight forward, remove the plastic cover covering the circuit / electronics. This was tricky and needed to go very slowly to carefully remove the three screws and coax the plastic cover off. Brittle plastic go slowly and use very limited force and of course check the power is off. Mains voltages in here. The grommets clip in place with very small tab either side. Small screw driver and very small force to pry out from the side. Look on the new unit to see the small tabs to give an idea.
So last tip is when you replace the new pump wiring thread the new wires over the top of the expansion tank before fitting. Opposite of removing the old one. Switch on and all should be good.
Apparently the new units are upgraded from the old ones and hopefully shouldn’t fail again, at least in the same way. It’s probably a couple pounds worth of magnetic switch at fault here which is annoying considering the cost, but time is money for most people so replace the unit and move on if doing commercially.
Little Update. Thought I would do a mini tear-down for those that might be more adventurous than me. Remove screw on bottom and pop base off. One screw and clip holding circuit board in place. Feed extra cable in to give some slack for movement.
So magnet ‘switch’ is a little more sophisticated. Appears to be a Laing board with no moving parts so perhaps initial thoughts on failing magnet reed switch is just wrong. Neat little watertight motor design I have to say. One mains lead to the relay and one to AC to DC power supply for use by board logic I suppose. Out of my depth here, but nothing serviceable to the average layman.