Intermittent Hot Water

[SunnyC]

Hi all

I moved a rad (this is where the problems started!) but knackered one of the valves in the process – so ended up draining the whole system (some of it through the kitchen ceiling).



Anyway, managed to fix it – put the rad back on & represurrised the system.



I bled the air from the radiators (but have since read that I should have been more methodical – I just bled from upstairs to downstairs).



The heating has been fine but we have now noticed that the hot water is hot & then goes cold for about 5-10 seconds before getting hot again. This has just happened, and the HW was fine before. Please could you advise? Do I need to bleed the rads again? Can I bleed the HW part of the system? (is air the problem??)



Any help, much appreciated!

 

[Softus]

Boiler?

 

[SunnyC]

Alphason Combi Boiler (sorry, thought I had posted that) - will check model when home....

 

[SunnyC]

problem seems to be worse upstairs with shower (boiler is downstairs). This morning, shower water was hot for 2 mins then became tepid. Have rebled all radiators.

 

[gigz]

Turn off the boiler and bleed from downstairs first then upstairs. Your diaphram washer could be split and need replacing, this could possibly be the cause of your hot water temp fluctuating.

 

[SunnyC]

Hi - thx for the advice. Finally got BG out (under homecare). They charged me 250 for a new DHW HExchanger - as it was blocked apparently. Now, nearly 5 months later - the same thing is happening. Except this time, they say I need a powerflush too! They are "willing", after some persuasion, to replace he HE for free, if I have the powerflush (£600!). Any advice guys? Can I clean the HE? I have some Ferroquest - am thinking of using it on the system (not sure if I should - i.e. is the HE aluminium?) but with the hot water tap turned on for a few hours (to divert the flow over the DHW HE).
Will this work? ? any advice gladly appreicated.

 

[Agile]

Its unlikely to do any harm but may not clear the plate HE.

Close the rad valves and use the boiler for DHW for a few hours. Then open the rads and use the heating for a day or so before draining and refilling with inhibitor.

All I can say is that an independent firm would be likely to be a lot cheaper for that kind of work.

Tony

 

[SunnyC]

Many thanks for the super quick reply Tony. Do you know if the Ferroquest product is suitable for this boiler (think you should avoid aluminium if poss)?

Also, I am a novice, so apologies but...

1. Should I close ALL valves? thermo and lockshield?
2. When you say use for HW - do you mean just switch it to HW mode only - or actually switch and run the HW tap continuously for a while?

Best

 

[SunnyC]

Sorry - should be a Alpha Combi (CB24 I think) boiler - not an ALPHASON!! (who make speakers I think?)

 

[SunnyC]

anyone still listening?

If i take out the DH HE and try to descale it, will I have to

- drain down? (only reason I ask, is that the BG guy didnt when he replaced it)

If I try to descale/clean the primary, will I have to drain and turn off gas?

Best

 

[2face]

bg always do this, scare u with a powerflush . 600 ???? were do they arrive at this sum ..
cancel the homeserve and get a local engineer to fix it for you.
up here powerflush is generally 300

the last 1 i bought came in at 150 ish inc vat ..

it is a part regularly fitted on alpha boilers so probably a weak point