I need to replace it (Cue for Rant: it was previously replaced in 199 - I thought these should last as long as the house! what's the matte with modern cylinders ?). It's a standard copper, indirect, vented on with 28mm pipework for the gravity-fed heating coil. The return fro the heating coil has a Drayton cyltrol mechanical valve, now wel seized up, as they all apparently do, and no longer working. So whil I'm changing the cylinder I'm thinking of adding a cylinder thermosta and a 2-port zone valve (to replace the cyltrol) e.g Honeywell L641 an V4043H. Hopefully it's a simple job to connect these to the programme and won't affect the rest of the heating system (unlike converting th whole system to fully pumped).
Various potential snags come to mind. The pipe connections to th cylinder are 1inch parallel BSP, so will need some jointing compound. The old ones seem to use some sort of translucent silicone compound. suspect PTFE tape won't be up to it. Any recommendations ?
When I fit a new (backup) immersion heater I'm a little nervous o using too much or too litte force (I suspect the old cylinder is no leaking due to the stresses caused by fitting the old i/h). Also, th immersion heater instructions say not to use any jointing compound although plumbers always seem to use loads of putty for this job. Wha should I use, and how much tightening ?
When I fit the zone valve and thermostat I want to connect to th existing Potterton EP3000 controller (user guide long gone). I assum this should do the job if I can figure out the wiring. Any hel available? Actually, the first problem will be getting the EP3000 of its backplate and getting at the connections - any advice ?
Reconnecting the heating coil will need some adjustment to the existin 28mm pipework, because the spacing between the connections is differen on the new cylinder. Although I've done a bit of soldering of 15m capillary joints in the past, I'm a little nervous of tackling 28mm. Would there be any problem if I dodge the issue and use multipl compression joints instead?
Are there any other potential pitfalls