central heating

[ryetee]

got a funny
central heating works but not the hot water heating
got a boiler from the 70's which seems bullet proof - guess pump works as the radiators get hot but get no hot water.
if the hot water is switched on one of the pipes into the hot water tank gets red hot the tank doesn't seems to
any ideas?

 

[breezer]

i am not a plumber or heating engineer.
a couple of things to check is there any water in the tank in the loft?
have you got an electric valve on or near the hot water cylinder like this (2nd drawing)

 

[ryetee]

thanks breezer
i was looking to see if i had one of those valves as well. i haven't.
strange thing is it seems to be working now having done nothing from my end - having said that the water dosn't seem to be as hot as it used to be

 

[alexnic]

Check to see if you have a cylinder 'stat, it is normaly fixed about a 1/3 up from the bottom and fastened by a metal clip. If you do have one it's possible that it is not working properly hence the reason for no hot water or luke warm water.

 

[ryetee]

alexnic - thanks for this
i was thinking about the (thermo) stat.
I'll go and check if there is one on the hot water tank but can't remember seeing one when I was feeling the pipes and having a nose round. If there isn't one what controls the temperature of the hot water - there is a 'stat on the boiler itself but how does it work - i.e what temperature does it govern (and here you'll understand I'm no expert) is it the temperature of the (gravity fed) water returning to the the boiler, the water rising to the hot water tank, is it the ambient temperature (I'm asking this as it has suddenly got noticeably warmer) the residual water in the boiler (if there is such a thing) or what.
Any help appreciated.
The boiler by the way is a Concord RS balanced flue gas boiler whatever one of those is!

 

[MANDATE]

I think I've got this right.
You control the temperture of the water in the boiler with the boiler stat,which controls the temperture of the water in the cylinder cause it can't be hotter than the boiler(boiler stat will close boiler down)
A cyinder stat controls the temperture of the water in the cylinder,but how?
Well it could take the place of a boiler stat I suppose and close the boiler down in the same way but it usually used with a motorised valve, so the stat is saying 'I'm hot enough' so divert the water to the central heating or if that is already satisfied or not 'on' then close the boiler down(with pump)
Room stats control the temperture in the room by either switching the ciculating pump off(when there is no motorised valve) or saying 'I'm hot enough' so divert the water to the hot water or if that is already satisfied or not 'on' close the boiler down(with pump)

 

[ryetee]

mandate
i'm sorted now - header tank to cylinder was empty - ballcock stuck in place as this tank only ever mpies very slowly. filled it up and it works like a dream. thanks to everyone for their comments and suggestions