Hi. This has a problem delivering hot water with heating off. It has a cam operated by a pushrod from the water valve. Observing the cam, it only moves about 2mm, not enough to make the dhw micro switch, and probably not enough to change the position of the servo valve. So the question is why? Is it likely to have a seized pushrod, or is the diaphram in the water valve? 25 years old, still works fine apart from this recent issue.
Thanks
Thanks