multiple replacement heat exchangers

[james75]

Hi All,

I have a problem with a Worcester Bosch Greenstar 24i boiler. It has had several heat exchangers over the last six years due to limescale build up, what happens is that the hot water supply loses pressure then it won't warm the water. The central heating continues to work ok.
A new exchanger was fitted in September last year, at the time the Worcester bosch engineer suggested fitting a limescale reducer, which was done at the same time. Since then, they have replaced the heat exchanger again in May this year, and currently it needs another one.

We are in a hard water area, but even so this seems excessive. I have spoken to neighbours who do not have this problem with their heating systems.

Any ideas what could be happening ? Worcester bosch seemingly want to just charge me £260 for a new heat exchanger each time, but I need to get to the bottom of why this is happening.

THanks.

James,

 

[Chalked]

You must be in a very hard water area. A "scale reducer" is just that, it reduces, but does not soften water. Sometimes they work well on an appliance, sometimes they don't.
as for your neighbours having no problem, maybe you use more hot water?
Best option would be fit a whole hose water softener, this will permanently stop the problem and help the rest of your plumbing too.

 

[mike76]

Water treatment on incoming main! Vulcanised water filter or something that will filter ! It might be expensive but heat exchanger wont have to be changed every six months!

 

[Ray Stafford]

Hi James75. Is this an ordinary domestic installation, or is it being used for commercial purposes - like a hairdressers or a restaurant kitchen? Its not a function of how much time passes, but how many litres of water pass through it and how hard that water is.

I have a similar problem and am in a hard water area, but it takes about 3 to 5 years for mine to scale up. If its scaling up in months on ordinary domestic usage, thats very unusual.

You might look at a Monarch Scaleout as a potential solution.

 

[Chalked]

Hi James75. Is this an ordinary domestic installation, or is it being used for commercial purposes - like a hairdressers or a restaurant kitchen? Its not a function of how much time passes, but how many litres of water pass through it and how hard that water is.

I have a similar problem and am in a hard water area, but it takes about 3 to 5 years for mine to scale up. If its scaling up in months on ordinary domestic usage, thats very unusual.

You might look at a Monarch Scaleout as a potential solution.

hi Ray
looking at the monarch scaleout. It looks like a large version of a fernox quantomat! Used to fit these years ago, but everyone forgot to replace the powder inside. Also without measuring the water usage, it's hard to tell when it's used up.
in my experience of living in a very hard water area (22 degrees!) . These products, when maintained properly seemed to just about double the time to scale up, but still scale up they did!
Weirdly, some properties would scale up fast and some never!.

 

[Roger Welton]

are you sure its limescale and not sludge on the heating side?

 

[mountainman]

I dislike Worcester's, change it for a proper boiler.

 

[Cello]

What about regular descaling options using a chemical descaler?

 

[THEJoeb]

Hi, Can you tell us the following?

general area lived? to check water board rating on hardness of water,
do you have a magnetic filter on the central heating?
has the Scale reducer been installed to serve just the boiler or multiple appliances?
when you say hot water looses pressure do you mean out the tap or on the gauge on the boiler?
do you have good cold water pressure?

I should be able to guide you to the solution if you answer these questions.

cheers

 

[Ermintrude]

Install a water softener it will remove lime scale as well as prevent it.

 

[james75]

Thanks for all the replies. To answer some of the questions raised:

This is a domestic house, three adults one child. It is in Maidenhead. The gas bills are normal, so I assume the water usage is normal.
The scale reducer that's fitted is an salamander electrolytic. It's connected before the supply to the downstairs toilet (where the boiler is), so does serve the cold water to the toilet tap too.
The house is quite small, as far as I can tell a softener is not really an option due to lack of space.
There is no magnetic filter.
The pressure is lost at the hot water tap (ie reduced flow rate). Pressure on the boiler guage and the cold water pressure are all fine. What happens is that you notice slower flow to hot taps, then you get a period where the water switches between boiling hot and stone cold, then flow rate slows further till you just get cold. Then Worcester come and replace the heat exchanger and it is ok, albeit for not very long (three months in this case).
There is other evidence of scale build up in the boiler apparently, Worcester have replaced other parts althought I'm not sure if this is just so they can charge for each call out (as if they only replace the part they replaced a few months earlier it;s covered by warrenty so no charge / commission for the engineer that comes out).

 

[plumb_know]

I had a new customer with same boiler having the same problem. I was there to replace leaking inline descaler, they had gone through about 3 exchangers in 2-3 years. I advised water softener or cheaper alternative of monarch scale out. I didn't realise how big the scaleout was until my first one a month back and very long flex's also washers supplied were fibre and leaked I swapped them for rubber ones, but apart from that customer happy with it so far and wasn't bad to install. Got some pics but can't upload them.

 

[plumb_know]

Ok one did upload.

 

[plumb_know]

Not sure how i did that, had to upload the worst one aswell.

 

[Riley]

Try a Scalemaster Softline 150 nice compact water softener. Will fit under most sinks

 

[plumb_know]

Riley, have you fitted many of them? Have customers still noticed the effects a year down the line?

thanks