Intergas DHW cycling hot and cold

[jonny5isalive]

Hi, went to my first Intergas breakdown yesterday, having been on the website as a Platinum 5 installer for a week.
Having been a Platinum 5 installer for a year

Combi compact 36/30.
The DHW is cycling hot and cold.
Same outcome on both kitchen and bathroom mixer taps.
Burner stays on at all times.
Flow is 11 lm cold, 8 lm hot.
DHW sensor possibly playing up as got 10k @ 22C
Scale inhibitor is fitted ( magnetic one tho) which Intergas is saying are inneffective. Anyone recommend ones that work?

Install not the best as

• no bypass,
• Iso on expansion vessel.....
• Benchmark shows only ratio and not CO2 max and min as in MIs. Was well out so I set it up as per MI's.
• Heating side dirty although No Nonsense stickers for cleaner and inhibitor. TF1 very dirty, pressure sensor needed a clean to register anything. Will flush another day as is separate issue I'd have thought.

Only thing Intergas suggested was that it is a hard water area (Bristol @ 200ppm) so it is scaled up. This correlates with the reduced flow of DHW as compared to cold? Surprises me tho as is only 2 years old. And I was sold on the Intergas because of it's large bore for the heatexchanger, especially for the HW.
Was going to suggest a clean with the scale remover I have yet to make from the thread on here.


Any other suggestions or experiences with these?

Tyia

 

[lame plumber]

my first combi was a myson years back and I had a magnetic scale reducer on it. HW flow gradually reduced over a year and it was down to the fact all the scale fell off the pipework over time and collected in the u of the pipework under the boiler. When the cold feed pipework was removed fm under the boiler and rodded!! all the muck fell out and normal service resumed Only seen this once thereafter but worth a look if all else fails.

 

[jonny5isalive]

my first combi was a myson years back and I had a magnetic scale reducer on it. HW flow gradually reduced over a year and it was down to the fact all the scale fell off the pipework over time and collected in the u of the pipework under the boiler. When the cold feed pipework was removed fm under the boiler and rodded!! all the muck fell out and normal service resumed Only seen this once thereafter but worth a look if all else fails.

Makes sense.Seemed the filling loop was blocked and so may well have been bunged with scale from the boiler. I changed it at the same time as cleaning the pressure sensor and didn't bother checking it.

Perhaps I'll suggest that their pipework gets a good rodding and see what they say.

I take it you don't bother with scale inhibitors?

Seems ironic that although Bristol seems to be on the map as a hard water area I haven't really come across much need for scale inhibitors on other boilers with plate to plate hexes. Let alone these.