Hot water cylinder temperature

[MattChan]

I was thinking fernox DS-3

http://www.fernox.com/?cccpage=ds3&sub=6

Or is that a bad idea that will make me glow in the dark?

Chemicals are for flushing the central heating, not sanitary water.

The instructions on the Fernox site imply that it goes in the sanitary water bit of the cylinder?

Connect a funnel to a suitable length of rubber or plastic tubing. The tubing should fit into (or onto) the cylinder feed connection on the inside of the cold water storage tank and the strong acid solution then introduced via the funnel,

 

[Softus]

Blimey it's like Piccadilly Circus in here.

 

[kevplumb]

it works but you have to make sure you flush it well out afterwards

 

[MattChan]

Is there anything that could be causing the premature scaling of my cylinder?

Boiler stat set too high. Cylinder stat positioned too low.

Maybe I got the height wrong here's a pic:

Its a 117L cylinder. Boiler stat is set to 70.

 

[kevplumb]

stat is too low as softus said

 

[MattChan]

stat is too low as softus said

Okey dokey. How High should I move it to?

 

[Nixt]

[quoteThe instructions on the Fernox site imply that it goes in the sanitary water bit of the cylinder? [/quote]


It's not illegal (so long as you don't allow it to back syphon to the mains supply) but in practice pointless. Hence chemical cleansing is really for CH side. If you see the scale when a bad cylinder is cut open, lumps the size of Mars bars. Imagine trying to strain whatever solution created through the water outlets or drain offs. A new copper cylinder is not expensive and its quicker to fit that what you're proposing.

 

[Softus]

Okey dokey. How High should I move it to?

One third up the cylinder. Also, is that stat actually touching the wall of the cylinder?

 

[MattChan]

The instructions on the Fernox site imply that it goes in the sanitary water bit of the cylinder?

It's not illegal (so long as you don't allow it to back syphon to the mains supply) but in practice pointless. Hence chemical cleansing is really for CH side. If you see the scale when a bad cylinder is cut open, lumps the size of Mars bars. Imagine trying to strain whatever solution created through the water outlets or drain offs. A new copper cylinder is not expensive and its quicker to fit that what you're proposing.

Makes sense

 

[MattChan]

Just had a look at the stat on the hercal cylinder at our lasses house and thats in the same place as mine as is this one I found on tinterweb

Is the hole for the stat cut by the manufacturer or have they all been done by the same dodgy installer?

 

[Softus]

Is your stat actually touching the wall of the cylinder?

 

[MattChan]

Sorry I missed that bit...

Yes it appears that the base of the stat is touching the cylinder. I've had a thermo couple held right against the cylinder and tested the cal on the stat v cylinder external temp and its within 3 degs or so.

 

[MattChan]

Took the immersion heater out today to investigate the inside of the cylinder... Inside the walls show no signs of lime scale. The inside is copper in colour with green pitting.

The heat exchanger was covered in limescale at some point but you can see where this has fallen off in places as huge bits are lying at the bottom of the cylinder. Then right in the center of the cylinder in the base there is something covered in scale that looks like its L shaped and pointing towards one of the sides.

How long do these cylinders last? Its been in 8 years.

I'm moving my bathroom / airing cupboard around so if its due for replacement I will stick a new one in when I move it all around...

Whats recommended to replace it with? Any makes to stay clear of?

Thanks for the help

Matt

 

[Softus]

Took the immersion heater out today to investigate the inside of the cylinder... Inside the walls show no signs of lime scale. The inside is copper in colour with green pitting.

OK - it's in good nick then.

Then right in the center of the cylinder in the base there is something covered in scale that looks like its L shaped and pointing towards one of the sides.

This is known as a sacrificial anode - it corrodes instead of the cylinder.

How long do these cylinders last? Its been in 8 years.

Your in Lap of the Gods territory. I've known them go in a couple of years, and others last more than 25. If the rest of the system is maintained properly, and the boiler thermostat kept at a reasonable level, then it'll go on indefinitely.

I'm moving my bathroom / airing cupboard around so if its due for replacement I will stick a new one in when I move it all around..

Not necessarily a bad idea, if your budget can cover it.

 

[MattChan]

This is known as a sacrificial anode - it corrodes instead of the cylinder.

I thought that may be what it was! It was covered in scale and white! Are the made of aluminum?

Is it best to get all the large chunks of scale out through the immersion hole or just let them be in the bottom?