Potterton Netheat works and heats radiators but no hot water

[Geminineil]

So.. we have a 20 year old (approx) Netaheat Potterton that comes on everyday and seems to be working okay.. the radiators get hot etc... BUT it isn't heating the hot water from the hot water taps (anywhere in the 2 bed house).

We do have an immersion heater that plugs in to I think the same hot water tank (I think it is the same one anyway) and only by using that can we get hot water.

Any suggestions as to what might be wrong and also how exactly does the potterton heat the radiators without heating the hot water in the taps?

Thanks in advance..

 

[stevetheplumber]

it will depend which system you have if you have a gravity system it will be the header tank ball valve jammed up and no water in tank
if fully pumped id say it will be a motorised valve
the water in the heating system runs through a coil in the cylinder to heat the water to your taps
neta heats were a great boiler in their day but all nearing the end of their lifes now

 

[Geminineil]

I don't think that it is a pressurised system....

 

[stevetheplumber]

preasurised is some thing different again

 

[Geminineil]

will it damage the system to keep running it if Stevetheplumber is correct?

 

[Geminineil]

we do get water from the hot water taps just that it isn't hot.... or rather doesn't get hot... when switching on the 'immersion heater (or plugging in) then the water gets hot..

 

[stevetheplumber]

probably not unless your pump runs dry

 

[stevetheplumber]

do you know where the pump is ?

 

[Geminineil]

we do have a 'header' tank in the attic (3rd floor) but I am fairly certain that is for the radiators...

1) is there another header tank for the hot water?
2) is the immersion heater a separate element within the hot water tank (ie separate to the hot water system pipes)

 

[Geminineil]

I know the cupboard where the pump is.. although I thought that was for the central heating... I guess there are 2 separate pumps?

 

[stevetheplumber]

inside the cylinder is the water that comes out of your taps within that is a coil that heating water runs through to heat the surronding water the imersion is a big version of whats in the bottom of your kettle and alsoheats the water

 

[stevetheplumber]

three story town house with the cylinder on the top floor ?

 

[Geminineil]

okay.. that is what I thought... so the two means of heating the hot water are within the same cylinder? -
is the header likely to be just above the cylinder or on the next floor above?

our Pottereton is on the ground floor - is the valve part of the boiler itself or is the valve next to the water cylinder (which is on the first floor)

 

[ecowarm]

As steve, try the smaller cistern the ball valve could be seized and tank dry, move the ball valve up and down a couple of times and let it fill up again

 

[Geminineil]

and to make clear... 2 storey house with a 3rd 'attic'
ground floor... Potterton boiler
1st floor cylinder with immersion heater lead and plug and pumps that I have seen...
2nd floor attic - radiator header tank - and not seen a 2nd tank there but there could be...

 

[ecowarm]

If its got no water in it (radiator header tank) thats your problem

 

[Geminineil]

Thanks for your advice on this.. very much appreciated.. if I could ask one final question.. how can I find out if the system is fully pumped or gravity? is there an easy way?

 

[ecowarm]

2 pipes from boiler fully pumped, 4 pipes from boiler gravity in general

 

[ecowarm]

Gravity and pumped flow and return are tee'd in above the netaheat

 

[Geminineil]

will the motorised valve be next to the boiler or next to the cylinder? (IF that is the problem)

 

[Whn1]

Most commonly next to the cylinder.

 

[jordand]

Havent read all this thread but my guess would be motorized valve, try opening manually

 

[glenno1]

Put hot water on and feel which pipes are getting hot are the pipes on the side of the cylinder getting hot

 

[Geminineil]

I do have a header tank in our attic that definitely feeds the radiators.. as I replaced radiator taps and put a 'bung' in that header tank which created a vacuum and I was able to work on radiators but does that header tank also feed the hot water pipes that go through the cylinder?


and - how do I do this? "but my guess would be motorized valve, try opening manually"

 

[jordand]

Motorized valve looks like a metal rectangular box, it has a lever on one side which can be moved over and jammed open
If in doubt youtube could be helpful