DIY Doctor UK DIY Forums

Hello,

I have a Potterton Suprima boiler which is about 6 years old.

I'll try and give a little information about the system :

- It has a control on the wall beneath the boiler which we use to select whether we want heating and / or hot water etc, and set the timings for these to come on / go off.

- We also have a water tank upstairs in the airing cupboard.

- We don't get instant hot water with this system.

We have had various problems with it, which have resulted in the following work being carried out :

- A New PCB board has been fitted
- A New Pump has been fitted in the cupboard upstairs
- A New Actuator has been fitted in the cupboard upstairs

1) We are now in the position where when we switch the water on, the heating also comes on ! (Not ideal in the summer)
2) If we set the heating to come on and off at a certain time, it comes on, but doesn't go off.

Can anyone shed any light on what this might be ?
Someone has suggested this may be more of an electrical fault as opposed to a plumbing fault, although I don't know.

Any advice would be appreciated.

Thank you.

Actuator on 3 port valve is at fault.

Instant hot water ? The suprima is not a combi.


There's many posts on how to check and repair actuator and 3 port valves, have a look through central heating forum.

htg

Thanks for your response, I appreciate it.

I know it's not a combi, I was just mentioning for completeness of information really.

Can I just clarify, when you say it's the actuator on 3 port valve at fault.
Someone has just put on a new actuator which is a square, white on top, grey on the bottom and it has a black switch that can go to auto or manual.

I believe this cost around £50 or so.

Is it this that is faulty, or is it something else ?
If it's something else, what would it look like ?

It is the part that you say has been changed that i would start looking at. Do you know if they checked the 3 port valve also, as fitting an actuator to a faulty valve is pointless (and expensive as the actuator may need replacing again, another £50).

Someone ? if an engineer get him back, as the system is still not working correctly.


htg

No there was no valve fitted with it, just the actuator itself.

How will I know if this new one needs replacing again ?

valve make and model would help a bit but ...

if you can take the head off some will say what position the spindle will be in to provide H/W, C/H or both so you can simply put it (in the spindle - should be able to turn it by hand, if not use a small spannr to free it up) in the H/W only position and see if the pipe that doesn't lead to the cylinder gets hot, if it does the valve internals are passing and need replacing.

if the pipe stays cold then you may have a restriction or blockage in the system causing the water to flow the wrong way (reverse circulation). the way to test this is run your radiators and make make sure you know which side gets hot first. allow it all to cool then run the h/w and see if it's that side of the other one that gets hot first.