rads pinholing

[welly2510]

hi, i work for a local council and we have a house thats had nothing but trouble with rads for the past 3 years. The boiler was changed late 2005 and since then the system has had 12 new rads! Some have only been replaced approx 5-6 months and they pin hole again, The system has had 4 powerflushes by 3 different companies, one even took all the rads off flushed individualy and then flushed the whole system. Its allways been protected using good inhibitor, think they have been using sentinal. Its even been double dosed. The rads still keep corroding and bursting. The tenent has said hes never had any running problems, it dosnt drag in air and hardly ever needs bleeding. ive looked over the system and cant find anything that would cause it apart from the system is allways sludged up even after 4 powerflushes, i have asked the tenent if he has seen the guys testing the dump water when powerflushing to make sure all the acid has been nutralised but he couldnt remember. Just woundered if any of you could shed some light on this as the tenent is elderly and getting very frustrated. thanks

 

[justlead1]

Hi Are you dealing with a sealed system or open vented? Have you contacted the rad manufacturer? they may cut open and Analise as to the cause, electrolysis, etc. I have come across this when copper tube has been inserted in to rads as an injector(when F & R are at same end of rad) to stop short circuiting on the panel. Also when pipe work errors have been made, cross connection to DHW system ( if the F&E are at the same level as CWSC it may not be easily identified ) Good Luck

 

[welly2510]

its an open vented system, surly it couldnt be the rads at fault, we only really fit one make of rad in the houses and its the only house thats like it. cross conection between DHW and CH, even if they were at same level surly there would be signs like hot water being discoloured. also how would that make the rads burst. other plumbers have looked at the system done little bits and said there you go, but it still happens. others dont seem interested so just trying to gain any possible answers as i can.

 

[justlead1]

Hi Panel rads will not last long on an open circuit as being made from steel they corrode quickly when fresh water is constantly present. If this is not the case, it can only be some form of electrolysis or the tenant is peaing on the rads and corroding from the outside in. Please post when you find cause of fault. Good Luck