Which type of hot water cylinder?

[Over The Hill]

Hot water cylinder has sprung a leak (seem to last about 12 years) and fairly useless lasting longer as they fill up with scale around here (this one is about a third full of scale).

Anyway, for about £220 I can get a new copper one or a new stainless steel one.

Only seemed to have copper last time I bought one. What do I go for?

Also, with a big lump of stainless steel in the system, am I passing or creating corrosion elsewhere that I would not get with copper? System is all copper with metal and iron radiators old style with header tank.

Thanks

 

[TissoT]

Where is the leak coming from !

 

[sight-pin]

Seeing as it's open vent, i'd stick to copper, tbh i didn't know you could get stainless for an open vent system.
The best system to have imo is a sealed system boiler with a mains pressure cylinder (megaflo) used to be tops but not sure now days.

Edit: What about installing an anti scale device on into the main tank?

 

[slowmotion]

If you have an open vented system with a pumped primary, I would go for a copper cylinder with a fast recovery (oversized) coil. Recovery times can be as low as 15 minutes. This means that the cylinder itself can be much smaller (therefore cheaper) and also the heat losses will be reduced too. BTW, remember to choose a Grade that will cope with your static head (vertical distance from the base of the cylinder to the water level in your cold water tank. I think Grade Three is good for 10 metres.

 

[cosmicbike]

Stick with copper. My mains pressure cylinder is stainless, and has a pair of sacrificial anodes which are checked annually and replaced when 'worn'.

 

[Over The Hill]

Where is the leak coming from !

Thanks for responses.

The leak is coming through the copper sheet near the immersion heater. Heater is broken so I was replacing that and had to ding it a bit to get it off. Copper is not deformed at all but is leaking.

Water here is very hard and the scale build up is bits that have formed on the heating element and then dropped off into the tank.

I had never seen stainless steel tanks before so was not sure if they were a good idea or not.

But consensus seems to be to stick with copper.

I do put stuff in the heating system but that is running mostly on the same water going round while the hot tank is new water all the time. I will see how the pipes are looking while I am there. Screwfix do a grade 3 tank that takes a 10m head but mine is probably more like 2m.

I put the system in 25 years ago and have replaced the cylinder once before so I guess it is not bad going really.

My job for the morning.

 

[Gravity Aided]

Water heaters will last longer if you change the sacrificial anode.
http://www.plumbingsupply.com/anoderods.html

 

[Over The Hill]

UPDATE
New one is in and all working (OK one small leak).

It was quite a job, cupboard is rather tight and has the loo in front of it. Old tank was so full of scale I could not lift it out so I cut a hole in it and scooped out three builders buckets of scale. Generally it is forming on the emersion heater or the coil and then dropping off into the tank.

My conclusion is that the tank, emersion heater and scale build up are all lasting about the same length of time (found date on old tank) 14 years, so not worth getting any one of the three to last longer.

I also replaced the hot out pipe that had got badly scaled up but only for the first foot, after that it is OK. and even got some stuff to put in the central heating system.

Thanks for your advice and feedback.