Help with Unvented Immersion Heater (brand is Ariston)

johnc

Hi,

I just moved into my newly purchased flat (finally could afford to buy a flat) and have found that my Immersion heater is leaking. Well I called out the plumber and they said it's the overflow pipe thats going and its that which is leaking. Apparently the overflow pipe should not be going at all. They recommended to replace the Immersion heater because there's a problem most likely with the Immersion heater that's forcing it to use the overflow pipe - and get a new one (I told them this one was probably about 10 years old).

I'm wanting to get a second opinion before dishing out yet more money on my new flat. Do I really have to get the Immersion heater replaced and is this the best thing to do rather than replace just the element or something? I have tried reducing the temperature but that doesnt seem to work as occasionally it stops the overflow pipe but when I raise it back to the level where the water is more than just lukewarm then the overflow pipe starts going again.

Its an Ariston Contract Std 125 Direct that is Unvented and only Electrically heated - Two parts of it which I assume is the Economy 7 and topup tank.

Be great to get some help as I have no idea whether I really have to replace the whole immersion heater or what?

Thanks in advance!

southcoastrgi

if the overflow that is leaking is attached to the tundish (see pic below) & the cylinder isn't overheating then it's one of three things non of which are due to the immersion heater, either a faulty prv on the incoming multicontrol or faulty temp/pressure relief valve on the cylinder or knackered or de-pressurised expansion vessel, non of which will require a new cylinder, you need someone with the G3 unvented cert to look at it not just a normal plumber

johnc

Thanks for the reply!

Yes the overflow that is leaking is attached to the tundish. Though the cylinder does seem to be overheating and I tried to turn the temperature down but then the water was not warm enough. Every time I turn it up to something thats warm enough it would seem to overheat and the overflow pipe would be going.

So does that mean it could be the Immersion heater then?

Thanks
John.

southcoastrgi

If it's overheating then it's the immersion heater stat & needs a new one, if it drips when it overheats then the temp & pressure relief valve is the one that's operating this is set to open at 90d, no drain down regd, just a new stat inside the immersion, I imagine if it's all electric you have two immersion heaters & economy 7 ? If this is the case the bottom one is normally wired to economy 7 & the top one to the normal supply you will have to see which one is faulty, they should both be set to 60d

johnc

Really great help I have to say. You obviously know what you're talking about and its helped me in talking to plumbers today because I am telling the plumbers what you have said and I can weed out the ones that have no idea! First by asking for a G3 unvented cert which many do not have.

Well basically every time I turn the temperature up to a reasonable point that the water is warm enough from the taps, the overflow pipe starts kicking in.

Yes, all electric, there are two immersion heaters, one economy 7.

Would it be more cost efficient and electricity efficient to get a new immersion water heater. The original guy had said with a new heater you know its going to be more cost efficient, have an electronic timer (rather than the current manual one) and work completely rather than fixing this that may have more issues in the future?