Long Standing Central Heating Issue - Anyone Advise?

[dfrbrowne]

My boiler is a Potterton Suprima 40.

Main Problem:
I seem to have no control over the temperature, thermostat in lounge seems secondary to thermostat on emersion heater.

eg: if temp dial on emersion heater is on 65 the radiators will not get hot but water will and boiler will be alight.

Temp on emersion heater has to be at max for radiators to get hot. They will not take notice of room thermostat and house will then get too warm and overheat. The water will also be scalding hot.

Even so at some times the heating and water will be on but the boiler will not be fired up and the radiators will be cold.
To get over this I have to switch it off, reset it, empty hot water out of tank and move dial on room thermostat anti- clockwise till it clicks and then clockwise till it clicks again and then switch on boiler again! I may have to do this or a combination of this several times to get it fired up again.
I must be wasting a fortune in gas bills.

Other clues to the problem may be that in summer, I switch the heating control off and just have the water to come on but even so the radiators will get hot. I have had to switch the dial on every radiator to min to prevent them heating up.

One guy said my pump needed replacing another said it was a wiring problem on the emersion heater thermostat

I am at the end of my patience now, I'm even prepared to get a new boiler!

[johnk]

It does sound as though your pump is either not working or it is airlocked and not pumping water around the system.

[buildersmate]

..... not to me it doesn't - otherwise the radiators wouldn't heat up at all!

Firstly the Suprima is a 'heat only' boiler which means it doesn't include the system components like pump and controls as part of the Potterton package. So the fault is not with the boiler, in my opinion - it is the way it has been wired up incorrectly by the installer.

Secondly, do you have a three-way valve in the circuit - often mounted near to the DWH tank? It has three copper pipes going into it with a with a central body and a motor (so a mains cable running to it). This device switches the pump such that it either sends hot water through the DHW tank, or around the CH, or both at the same time.

If you do have such a device, it appears either not to be working, or it is incorrectly wired up. Answer me that first, then I (or someone else) will suggest how to fault-find further.
It may not be possible, but we can try.
You may end up needing a decent heating technician - not necessarily a plumber, unless he installs complete CH systems. This is an electrical problem.

[Iggle Piggle]

This boiler is the 'plumbers nightmare' ! I have one and was plagued with faults, problems and constant resets.
I found the circuit board in the Potterton Suprima 40 is full of solder dry joints, which can cause all sorts of random problems, including yours.
The best way is to replace the circuit board. They can be anything from £80 to £120 but if you know a decent electrician or tv repair shop they may be able to 'reflow the joints' on the board cheaper once it is removed from the boiler ( a 5 minute job for an electrician.)
I did mine myself and have had no problems since.

[gucciman]

i think you are mixing up your terminology here. An immersion heater is an electrical element in your hot water cylinder and has nothing to do with your boiler or heating circuits at all, you should only be using your immersion heater as an emergency back up if your boiler is broken. I am guessing what you are talkiing about is actually the thermostat on the control panel of the boiler?

as for your room thermostat, firstly it should not be in the lounge as its operation can be affected by the presence of any other heating such as a gas or electric fire. secondly, is the room stat could be faulty or not actually wired up into the system, believe it or not we have come across several room stats screwed to the wall but the installers haven't actually bothered to wire them.

difficult to diagnose the fault (s) without seeing your system but as builders mate says if you have a y plan type system with a mid position valve or even another type of system with zone valves then yes i would be examining the valves for faults .

and yes the circuit boards can be a problem on these boilers, they tend to overheat and when we replace them you often see scorch marks on the boards where a component has failed.

you really need to call out a heating engineer.