hot water cold rads

[guest101]

I am after some advice and guidance. I have an ecomax 635 hooked up to a unistor cylinder. I have a ground floor flat with 9 rads and under floor heating. System has always struggled to supply heat to last rad but has managed some warming. In trying to improve the heat from the last rad i closed down all the other rads and u/floor heating. This had some success, however i now have no heat to any of the rads. This was described as being an air lock ( vaillant engineer came to check boiler as under two years old, boiler ok). So have now bled the system several times, lots of rusty stuff but system flushing through clean now.

Each time on recharging the sytem the boiler makes an incredible amount of banging noises and will cut out with either a F23 (temp range too wide) or F24 (temp rises too fast) fault code.

Cannot get through to vaillant to ask them so thought i would offer the problem to the forum.

Any advice
Icers from Bristol

 

[ChrisR]

Lack of water (pressure) or excess of air. Make sure the aout air vent in the boiler (looks like a car tyre valve, by the pump) has a loose cap.

Then you task is "balancing" - see faq.

 

[guest101]

ChrisR

Thanks for your response, water is ok, sits between 1 and 1.5 bar. Have located AAV, the plastic cap is loose.
could the fault lie within the AAV and if so can they be stripped down and cleaned

Cheers

 

[bengasman]

If lots of dirt came out, there is a pretty good chance there is a lump of sludge stuck here and there. Start of with adding a bottle of HYPERFLUSH in the system and let it circulate. Flush it out again until clean

 

[guest101]

Thanks again for the interest and advice.

Latest update from icers in bristol is that the AAV was sticking, had pro plumber strip it down. AAV full of black greasy gunk, showed him size and quantity of collected residue from flusjing system. In his words "would expect that from a 20 year old system not a 2 year one". We had a small leak on the system last year, blown joint on old pipe work. Remember pro plumber that came to fix it used a "radweld" type additive to fix leak from inside.

New plumber diagnosed heat exchanger trashed due to residue from sealant and excessive rust accumulation from leak letting air into system, and the rapid heat recycling of the system 107C down 47C in minutes.

So am now in need of new heat exchanger before xmas.

Thanks for website and the help

Cheers