Gledhill Boilermate 3 heat exchanger - 4 in 11 years??

[eserim]

Hi

We're about to change our plate heat exchanger in our Boilermate 3 for the third time - the house was built in 2000, so about 4 per decade.

Whilst at £110 it is cheaper than replacing a furred up tank, but is this normal? We are in a slightly hard water area - not as hard as I have had in the past. Sorry, no exact samples.

There is a "factory set" mixer on the heatstore, that appears to mix some of the heated water back into the input of the heat exchanger - I'm guessing that this will affect how hot the water gets heating in the exchanger, and therefore how much scale is formed - anyone know if this is right? If so should I increase/decrease this ratio to get a better life.

When a new exchanger is working, I think this system is great, mains pressure hot water as advertized, but after a few years.....

Cheers

Eserim

 

[45yearsagasman]

The blending valve does exactly what it says on the tin, blends very hot water with cold to prevent scalding, and should not be adjusted unless you know what you are doing.The store should be at near 80 deg C. What side of the plate exchanger is "scaling up"
It may be the primary side and not the heated water side. If its the primary side then its system water and these appliances are notorious for sludging up
Ever considered fitting a scale reducer or water softener if you have hard water?

 

[eserim]

Cheers - we've always assumed it was the heated water side, not the system - any easy way to tell, apart from cutting one open?

I may look at plumbed in softeners, but the running costs may make a £110 exchanger, every three years still the cheaper option. Of course, if spares became hard to get then we may have to revistit this.

Cheers

Eserim

 

[eserim]

...thinking about it, I guess it must be the hot water side, as the pressure is reduced, from what it was when new. If it was the system side, surely the pressure would remain, but the temperature would be reduced?

Cheers

Eserim

 

[45yearsagasman]

Yes you could be right. Examining the removed heat ex will prove which side is blocked for sure.

 

[dcawkwell]

Put a limescale reducer in line.

That should stop it or make them last longer.

They only cost £20-40 pounds.

 

[simond]

One of the leading heatstore manufacturers used to recommend the Hydropath electrronic water conditioner.

Costs less than a heat exchanger; trouble is, no one can fully explain why they work, but apparently BG put a lot of money into the development and were satisfied with the result.

We haven't seen any problems on heatstores where this is fitted, but the numbers are small, so it is anecdotal rather than scientific!