I have a 36"X 18" (92 X 46) hot water cylinder and the immersion heater has stopped working. Can anybody tell me the heater size (length) of the one I need to fit that cylinder please? I know I can remove and measure but with so many shops closed I want the right size heater to hand before I start.
Can I just reiterate what bhg481 said about taking great care when unscrewing old and screwing new heater - cylinders are very fragile and can easily be bent, even destroyed (been there, done it).
Given the delicacy of the cylinder and the fact that many retailers will give you a full refund on unused goods (Screwfix certainly do) I'd consider getting a new cylinder as well as the heater, particularly if you have an old cylinder and live in a hard water area.