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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> Combi boiler https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1288553999 Message started by petrolhead on Oct 31^st, 2010, 7:39pm

Title: Combi boiler
Post by petrolhead on Oct 31^st, 2010, 7:39pm

Hi this is my first post so please be patient.My problem is the lack of dhw,i have a Baxi 105e instant combi boiler.Last week i fitted a new limescale remover to the incoming water pipe,i also fitted a new inline filter onto the filling loop and while the system was drained put conditioner into the c/h system . After checking every thing i filled the system via the filling loop and every thing seem to be ok and the boiler started as it should,c/h worked fine but on opening the hot water tap either luke warm water or cold ran out.Today 31/10/2010 i fitted a new diaphram and things were a little better but still no constant hot water.I tried turning the d/h/w pre heat off as recomended by a plumber but the system kept switching between c/h and d/h/w about every 2-3 seconds but stopped if i put the pre-heat on slightly.Prior to draining the system last week everthing worked fine,pressure is about 1.8 bar,is there anything else to check or adjust.Any info would be greatly appreciated.Thanks

Title: Re: Combi boiler
Post by CWatters on Oct 31^st, 2010, 8:57pm

Is the limescale remover a water softner? If so try bypassing it temporarily to see if it's the pressure drop across that is causing the problem.

Title: Re: Combi boiler
Post by petrolhead on Nov 1^st, 2010, 8:57am

The lime scale inhibiter is a Salamander Sesi Electrolytic Scale Inhibitor which is fitted down stairs on the incoming water supply to treat tthe whole house and coupled using compression joints,i don't have anything to bridge the gap if i remove it but i am going to check the filter in the boiler first.The pressure within the boiler stays constant.Thanks.

Title: Re: Combi boiler
Post by CWatters on Nov 1^st, 2010, 12:47pm

I'm rather a sceptic when it comes to such devices. There are plenty of people who say they they work but most scientists/Chemists consider the explanation for how they are meant to work to be mumbo jumbo.

The only devices I've heard of that seem to have a valid scientific explanation are the magnetic devices designed to trap iron based corrosion products in CH systems....but I feel that putting corrosion inhibitor in to prevent it in the first place is better.

I suspect the one you have won't have much effect on the pressure. Did you look through it when you fitted it?

A lot of these devices claim to cause the calcium in the water to precipitate out but in a "non-sticky" form. Perhaps that precipitate has blocked the boiler filter?

If that's the case perhaps put the filter before the scale inhibitor?

Title: Re: Combi boiler
Post by petrolhead on Nov 1^st, 2010, 10:32pm

I checked the filter prior to fitting and the filter in the boiler today ,both seem ok.I have good flow and pressure to all taps and to the boiler,by the way the combi is a Baxi 105e instant,i don't know if it makes any difference.

Title: Re: Combi boiler
Post by petrolhead on Nov 10^th, 2010, 3:50pm

Thanks to everybody,after replacing the d,h,w diaphram,thermister,pressure relief valve and micro switches/loom everthing seems to be working ok.