Potterton Ultra Boiler constantly heating water

[GarethMike]

We have a Potterton Ultra 15 (5 years old) which is constantly trying to heat water - there's no pull for hot water.

I've checked the pressure - sat at 1.5 psi - tried a reset but nothing. Tried the manual, which is pretty poor to be honest on trouble-shooting.

Any ideas?

 

[terryplumb]

- there's no pull for hot water.

What does the above mean ??
Do you have a programmer / timer ? Do you have motorised valve/ s ?

 

[GarethMike]

We haven't got any hot water taps on demanding hot water from the tank and then for the boiler to top up the tank.

 

[GarethMike]

All timers/program control is off. Not sure about the motorised value control

 

[terryplumb]

Take some pics to show us of around the hot water cylinder , looking for any thing that looks like a box fitted on pipework,with electric cable coming out of it.

 

[GarethMike]

Here's the tank

 

[Deleted member 267285]

Looking at your wiring, there’s at least 2 of these, and these are motorised valves. They tend to have a microswitch stick which continually calls for a demand even though there isn’t one.

 

[GarethMike]

Thanks @CBW and @terryplumb, it appears that the bottom one was not working properly - gone loose. Off for now and I'll sort a new one tomorrow.

Thanks all!!