Saunier Duval warm hot water, hot rads

[zanwan]

http://www.saunier-duval.co.uk/manuals/pdf/current_products/installation_ThemaF30e.pdf

Sorry, just had a look through manual, the heat exchanger on page 36 of the above manual looks very different from the one in the pic you sent me. Is it definately the one in pic on page 36 (described in step 17.11, page 35) that i remove?

 

[mickyg]

no thats the main heat exchanger. wrong one

look at 20.34 page 55.

 

[zanwan]

Hi Mick

Carried out the work yesterday. Removed the plate heat exchanger. Had a look, there were little black specs of dirt falling out when i flushed it through with a hose. Not loads but a small amount.

The two holes at the top, when looking thrugh them, it looked black. The bottom two holes looks clear.

I descaled it twice using Oust descaler. Fitted it, and now getting hot water! Brilliant!

One one minor problem though, i left the hot tap running and had a look at the flames on the boiler and noticed that the flame would start up, go high for about 3-5 seconds, then low for 3-5 sec, then off for 3-5 seconds. Then it would fire up again in the same sequence. I checked the hot water at the tap and noticed it went from warm, to hot, to very hot, then hot, then warm, and this cycle repeated itself.

Personally I can live with this, however I dont think its supposed to do that is it? Any idea what could be causing that?

Many thanks for the help so far! My wife now thinks i'm the bee's knees as she was constantly pestering about the lack of hot water!! Got a big roast last nght for my hard work lol

 

[Agile]

I suspect the plate still contains a considerable blockage.

But if you are now happy with the hot water you can leave it until more dirt gets into it from the system.

Your system should ideally be flushed or have a magnetic filter fitted.

Tony

 

[zanwan]

I descaled it twice and flushed it out for a while using mains pressure. The water did seem to flow pretty well, althought the botton half (inside) of the heat exchanger was still black after the deslcaing, with only few silver shiny bits appearing.

So you think it may still be blocked?

Is their any specialist powerful descacler that plumbers would use for something like this?

 

[Agile]

Can you tell me what chemicals you used to "descale" it?

Tony

 

[zanwan]

erm not sure, it was the Oust descaling solution i brought from Tesco. Identicle to this:-

http://images.google.co.uk/imgres?i...images?q=oust+all+purpose+descaler&hl=en&um=1

Please dont tell me i've just wrecked my boiler!!

 

[zanwan]

*bump*

anyone know if using oust to descale the heat exchanger will damage it?

 

[mickyg]

*bump*

anyone know if using oust to descale the heat exchanger will damage it?

very much doubt it.