Mega Flow / Santon immersion heater elements.

[rekab69]

Hi Guys,

I am getting through the above elements like no tomorrow.

Installed new 210 Solar (solar not connected ) Mega Flow, elements lasted 6x months. replaced them, next lot lasted 5x months.
Then a weld on the stainless steel PRV stub failed.

New Santon cylinder supplied under guarantee.. Santon elements lasted 2x months.

I had spoken to Mega Flow technical department about a de scaler, they did recommend any.

Also stated that a water softener would attack the stainless steel..

I found (at a price!) a no salt water softeners..

A Combimate has also been recommended..

Any ideas..?

Cheers,

Dave.

 

[picasso]

Softened water wont attack stainless steel, I would have your electrical system checked out as a cause for the elements corroding so quickly.

 

[muggles]

Are you on a normal mains water supply, or a private supply? Some private supplies are really quite corrosive.

Two things to do - get your water tested, and get your electricity tested. Something may be causing electrolytic corrosion, in which case you'll need to have additional equipotential bonding fitted.

A simple test of your water would be to obtain a piece of stainless steel, preferable a small thin sheet, dunk it in your water for a month or two and see if it changes. A better test would, of course, be a full chemical analysis.

 

[rekab69]

Thanks for your replies.

I tested the earth a couple of years back when our Aga cooked it's self, the ESSEX trip switch Errr.. didn't..!

We are on over head electric supply, PME...? rings a bell. I'll check it out tomorrow.

Water supply is mains fed..

One thing I neglected to mention is we have two hot water cylinders running at the moment, the unvented and a conventional open vented system which has had the same two elements in for the last nine years that we have lived here and so are a lot older than that..?!

Thanks.

 

[muggles]

Sounds most likely to be an earthing issue then. Time to call a sparky in...

 

[rekab69]

Sounds most likely to be an earthing issue then. Time to call a sparky in.

Hi,

Just got of the phone to my old pal George an electrician I use on my jobs, he is baffled as to how this could be due to an earth fault.

He has gone away to talk to a younger more up to date, eager to please sparky.

Can I trouble you for your thoughts behind this so I can pass it on please.

Thanks..

 

[muggles]

Old place I worked in once had a similar issue, with things corroding very quickly - they had the electricians in earth bonding all the pipework together and found the problem was significantly reduced (although, I have to say, not completely eliminated).

 

[Fluffster]

Your elements could be acting like a sacrificial anode.
Pete

 

[rekab69]

Your elements could be acting like a sacrificial anode.
Pete

Hi Pete,

That is correct, I guess as our other cylinder is copper there is a different set of metals involved.

Our stainless cylinder isn't being attacked (because it's a harder material..?) so the elements are taking the full load of corrosion.

Wonder if an anode like on a boat is the answer..?

Still trying to get my electrician to come and have a look.. better hurry up or I'll be out of elements by the time he gets here..

Thanks..

 

[Agile]

All elements used should be Incaloy and resistant to attack.

But you have not told us exactly how your elements fail.

Are they just going open circuit?

Have you monitored your mains supply voltage over a 24 hour cycle?

Tony

 

[rekab69]

Hi Tony,

The elements are scaling up with lime scale.

They are well and truly open circuit, split open & twisted in one case..

I haven't monitored the mains voltage, how often would this need to be done, in a 24h period...

Thanks for you advice..

Regards,

Dave,

 

[picasso]

This might explain why your elements are failing.

http://www.rheem.com/docs/FetchDocument.aspx?ID=aedbbc95-9a6b-4780-aa23-b0ed9abe41cd

 

[Agile]

Right scaling up.

Obviously you need a scale reducer or inhibitor.

The polyphosphate types work well as long as they crystals are kept topped up.

There are some electrical types, mostly NOT worth trying.

Magnetic ones will work if the water flow is reasonable as the effect they create only lasts a few hours.

Tony