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These electrodes deserve a page of their own, especially now Potterton have unhelpfully discontinued the earth electrode which needs replacing periodically.
Here again is a photo of an eroded earth electrode ready for replacement, next to a new earth electrode fitted to the pilot assembly and ready for fitting back into the boiler.
Notice the difference?
The eroded top section in the left hand photo is significant because the process by which the control board detects the pilot flame, relies on the surface area of the horizontal tongue above the spark electrode being correct. When it erodes away like in the left hand photo, flame detection becomes unreliable and the main burners in the boiler fail to light.
Until recently the fix for this has simply been to fit a new earth electrode as in the right hand photo. Now this part is discontinued, a boiler suffering from this can still be repaired with a bit of ingenuity, a drill and some stainless steel sheet I suspect. As of today (Wednesday 18/11/20) I am investigating how to do this in detail and expect to come up with a solution shortly. Broadly, I plan to cut a strip of 0.7mm thickness stainless steel from ebay to the right size, and attach it with a small stainless steel nut and bolt, to replicate the missing metal.
I’ve now completed a first attempt at repairing an earth electrode, using redundant metal cut from the base of the electrode to create a new tip, which I have attached using a screw, nut and lock washer.
Here is a photo, showing three electrodes. Top left is a ten year old worn out electrode, top right a brand new electrode, and in the front is the electrode I’ve repaired, using a hacksaw, a drill and a nut & bolt:
Notice how I’ve cut a piece of material out from the side of the repaired electrode in order to create the new ‘tongue’ on the top. You could copy what I’ve done here to repair yours if you feel competent. Here are the same three electrodes shown from a different angle:
And below, a closer view of the ‘hacksaw and drill’ repaired electrode.
Anyway, the point of all this is that I’m getting a steady trickle of calls asking if I can supply new earth electrodes. I’m afraid I can’t, so I have written this page to explain my potential work-around, crude though it is. I’ve yet to fit one of these into a Netaheat Electronic to see if it works so I offer no guarantee, but I cannot imagine it not working perfectly well. if you need a new electrode then I doubt you’ll find one, but as you have been resourceful enough to realise you need one, you are I would imagine, perfectly capable of copying this work-around.
I’ve now developed a better repair for these electrodes. I now cut and form a new piece of stainless steel into an ‘’L” shape, then spot-weld it onto the the old eroded electrode base instead of using a nut and bolt. This makes a much more professional repair. Here is a photo:
This is what I’ll use to repair your Netaheat should the fault turn out to be an eroded earth electrode.
If your boiler has broken down contact me for free help and advice by phone or text. I can arrange to visit and repair if necessary.
If you book a visit I shall wear a face covering (and gloves where practical), and observe social distancing.
Copyright Michael Bryant 2021
Site first published 11th November 2010
Last updated 25th April 2021
Gas Safe Register 197499, CIPHE registration number 56207