Central heating fault advice

[stephens]

I have a Worcester Bosch 28i RSF combi, sealed sytem fitted new December 2004 (not sure if it was flushed correctly on install.) The Auto Airvent leaked and was replaced after 9 months, then 7, after which it was cleansed for two weeks with Sentinel X400 and Fernox MB1 inhibitor added.
The vent then leaked after 12 months, 15 months and just now at 9 months!
It never loses pressure unless bled, but when on in the colder months the bathroom radiator (which is always on to prevent short cycling) gets colder at the top and is bled once per month (losing 0.1bar approx per 2 months.) I am not sure if it is the return side of the pump and has a micro air leak, no other rads need bleeding.
It smells gassy (hydrogen) even though cleansed/inhibitor 3 years ago.
Can anyone tell me the best thing to do next? If it was a bad install may I have to power flush? I am worried about a power flush causing underfloor leaks.
Also what would happen if I fitted a Aladdin Autovent to the bathroom radiator and closed the Auto Airvent on the boiler to prevent leaks whilst away on holiday etc.?
Many thanks for any advice given.

 

[bengasman]

By the sound of it, it was a bad job. The i-series is favoured by cowboy installers anyway, so the two together give you a pretty good chance that it was not cleaned upon install, and when it was finally done, it was probably not done right.
Before splashing out for a powerflush, search the forum for flushing and check the faq.
The bottom line with a flush is: get the dirt out.
Sticking a chemical in is not a magic trick; it just loosens up the dirt/limescale/rust. Once it is loose and suspended, it needs to come OUT.
Then you put inhibitor in and top it up every 3 years.

 

[stephens]

Thanks for that bengasman. The installer himself was said to be good but one of his employees may have done the job. We moved in 6 months after it was installed (house left empty.) I have read lots of the Flushing posts but most are for new installs or old sludgy sytems. Not sure where that leaves my 5 yr old system with a probable bad install. Is it the solder flux I need to get out rather than sludge?

 

[bengasman]

It does not really make much difference what is in there, or why it is dirty. It just needs to be clean.
A chemical clean is not that difficult. If you follow the advice as laid out in faq, and install a magnaclean afterwards, you have a good chance solving the problem once and for all.

 

[stephens]

Thanks again bengasman. I will follow the faq advice and fit a MagnaClean.

 

[stephens]

Sorry to be a nuisance, but one last query. As it is probably a bad install originally rather than sludge building up in the system over time, would X300 be more effective than X400 for the chemical clean? The Sentinel website says X400 for sludge/oxide and X300 for install debris/flux etc.
Thanks again for any advice.

 

[bengasman]

After 4 years, you can't really call it "install debris", chances are your system is well and truly corroded and needs at least x400