Heating needs to be on to heat hot water

[davebwithane]

Ok, I got the Mrs to have a bath, she used up all the hot water (as usual )

I then switched on the HW only. The boiler started up. It's been on for 30 mins. Contrary to what I said earlier, the rads that are open upstairs did heat up ! and there is still no hot water..

There is no noise coming from the pump at this time.

 

[StephenW]

So, if the boiler's been running for 30 minute, how far along the pipe is it hot - just as far as the pump, the T-piece, or where?
Has it always been this way? If the same pipe is feeding the CH and the HW and there is no valve in either then you would need the CH to be on to run the pump so that the heat will reach the cylinder, which in turn will mean that the radiators will heat up. In that case, you need some valves fitted I would guess.

 

[lifesagasman]

well, thats a start, now we know the basics work to a demand for HW
are the pipes into the side of the tank warm? after 30 mins they should be, with one warmer than the other

 

[lifesagasman]

sorry, overlapping posts there. sounds like you may just have an incomplete system, ie no motorised valves. a temporary fix would be to turn off the upstairs rads to divert heat to the tank. long term fix get some valves fitted

 

[davebwithane]

The rads that have heated up upstairs are look warm, the room thermostat is turned down to it's lowest level.

The water started to get hot after 1 hour 30 mins. It normally takes 30/40 mins to get hot enough.

"well, thats a start, now we know the basics work to a demand for HW
are the pipes into the side of the tank warm? after 30 mins they should be, with one warmer than the other"
Yes the inlet from the boiler is hotter than the outlet pipe ..

Not sure why the rads are on at all ? CH is off. Only HW on.

 

[davebwithane]

thanks. I'll get a plumber to check it out. Thanks for the advice. Where would the valves be required ? At the tee joint ?

 

[davebwithane]

not sure how the rads are getting hot because the pump only kicks in when the CH is on, not when the HW only is on.

 

[lifesagasman]

the rads are heating because they are taking hot water by gravity, same as the tank, as they aren't isolated by any motorised valves. when a plumber can see the pipe layout he can advise on the positions of valves. i wouldn't guess without being able to see it

 

[davebwithane]

Thanks very much for your help. Very much appreciated.

 

[lifesagasman]

you'll save a small fortune in oil once it's upgraded