help, no hot water

[glayzell]

I need the help of men who can empathise. I have no hot water and a pregnant wife who is not happy about the situation!

I inherited a fandabidozy 'Ravenheat 820/20' combi when i moved to my current house nearly a year ago. I am aware that these boilers dont have a great reputation, but unfortunately i am stuck with it until i have the pennies to buy a new boiler.

I had a very similar problem with the combi in my old house and think it may be a problem with the water as well as the boiler, here is the problem:

Boiler pressure is fine, over 1 bar, heating is working fine, but no hot water, the pressure of the water leaving the taps has declined over recent weeks and i now barely have a drip. the water is hot when the heating is on though.

I am guessing there is a problem with the diverter valve and /or the the heat exchanger is scaled up (this was the problem i had in the old house- very hard water, no flow through h/e in that case because of scale as well as problem with diverter). I cant hear the microswitch click when the tap is opened, i could until a month or so ago.

should i try the h/e first, before buying a new divertor?

any thoughts???

 

[kevplumb]

sounds as if it needs a descale

 

[glayzell]

is there a way of doing that without removing the h/e?

 

[kevplumb]

only if you have the pumping machine

you may be able to hire 1

 

[croydoncorgi]

Funny that...

Had same boiler with same problem yesterday. No limefighter fitted. It also seemed to me that this design is a 'limescale disaster waiting to happen': direct-heated HW exchanger which is bound to run at above the 'critical temperature' (for depositing 'temporary' hardness) when there's no flow of hot water. ie. most of the time.

I already condemned it as 'beyond economic repair'. There were leaks and other damage elsewhere in the boiler. But maybe I shouldn't have....

Perhaps Kevin will tell us more about the effectiveness of descaling the hot water heat exchanger in-place... I take it you meant: connect a machine across the hot water feed and cold water inlet connections. Well, OK - but what about the diverter valve diaphragm??? Given that on an oldish boiler this is going to be a bit flaky, what's the descaling chemical going to do to it? And which descaler to use?

 

[kevplumb]

you can do it that way i prefer just to connect to the h/e
then dont have the problem with the valves
i usally use kilrock
agree about flaky h/e the black viallant 1s where a git for perforating
as where the s/d
which i assume is the design you refer to

 

[oilman]

.......I have no hot water and a pregnant wife...........

So who wears the trousers? Stop bleating.