New hot water cylinder install questions

[paulradcliffe]

Hi, I am going to fit a new hot water cylinder in our airing cupboard as the old one's coil has split and causing the small tank to overflow

I have heard the cylinder connections can leak, so would like to ask how's the best way to stop them leaking/dribbling?! I was going to use PTFE tape around the threads and compounds too. Is this correct?

Secondly just to confirm to replace the cylinder, I drain the cylinder by closing the gate valve to the cylinder cold feed, open hot taps in bathroom, and drain ia the draincock near the cylinder.

To drain the primary circuit I will need to drain the whole heating system down too from the draincock near the downstairs radiator

When piping the new cylinder, as it's in a tight space, is it best to add a small pieve of pipe near the old ones before putting the new cylinder in place?

Have I missed anything out? Or is there anything I can do to make it easier?

Also when re-filling the system I'll add X100 to the small tank.


Thanks for reading my post, I will appreciate any advice or help given.

 

[muggles]

Hi, I am going to fit a new hot water cylinder in our airing cupboard as the old one's coil has split and causing the small tank to overflow

I have heard the cylinder connections can leak, so would like to ask how's the best way to stop them leaking/dribbling?! I was going to use PTFE tape around the threads and compounds too. Is this correct? Yes use PTFE and jointing paste

Secondly just to confirm to replace the cylinder, I drain the cylinder by closing the gate valve to the cylinder cold feed, open hot taps in bathroom, and drain ia the draincock near the cylinder. Yes although sometimes the draincock doesn't work, in which case you'll need to remove the connection at the top of the cylinder and siphon it out

To drain the primary circuit I will need to drain the whole heating system down too from the draincock near the downstairs radiatorNormally yes, but as you have an open vented system remember to shut off the supply to your loft tank before you start, otherwise you'll be draining forever. When you fit the new cylinder, put gate valves on the flow and return to the cylinder, and a draincock, so next time it needs changing you only need to drain the coil, and you can keep the rest of the heating system running. An auto air vent at the top of the coil is also a good idea. Remember to turn off the boiler to avoid running it with no water in it as you're having to drain the entire system

When piping the new cylinder, as it's in a tight space, is it best to add a small pieve of pipe near the old ones before putting the new cylinder in place? Do whatever you think you need to do to make it easy for yourself

Have I missed anything out? Or is there anything I can do to make it easier? Give yourself plenty of time, it will take longer than you expect. Make sure you have all the required cylinder fittings before you start. If your old cylinder is very old, you may have imperial 3/4" pipe rather than 22mm, so get some adapters before you start otherwise you'll find yourself in a sticky situation

Also when re-filling the system I'll add X100 to the small tank.


Thanks for reading my post, I will appreciate any advice or help given.

 

[holty]

When you fit the new cylinder, put gate valves on the flow and return to the cylinder, and a draincock, so next time it needs changing you only need to drain the coil, and you can keep the rest of the heating system running.

not good advice without seeing the system layout.in some circumstances, if both gate valves are shut off.it can cause serious damage.e.g vent on flow to cylinder coil, and feed off the return off the coil.as in older layouts this was the norm .i can see were muggles is coming from.but if your unsure of system layout it could cause problems. if isolaters were put in the wrong position.

 

[muggles]

Good point Holty, I forgot to add that the heads should be removed to prevent unwanted operation. We always tie tags around any valves we install, cylinder ones like this get marked engineer use only (and the heads removed of course) just to be sure

 

[Boilerman2]

Thats still not good practice though regulations state NO VALVE SHALL BE FITTED BETWEEN A BOILER AND ITS OPEN VENT

 

[muggles]

Thats still not good practice though regulations state NO VALVE SHALL BE FITTED BETWEEN A BOILER AND ITS OPEN VENT

Yeah OK, I'm digging a small hole here... OP check position of open vent and make sure the valve these guys don't want you or I to put in isn't between the boiler and the vent