Potterton Netaheat 10-16

[Ed123]

Hello

I've been in the new place a couple of months - when I moved in the heating switched on when requested but now only the hot water works

I replaced the Horstmann 425 control unit with a Horstmann H27 XL because the 425 was not switching the water and heating off when it was supposed to. I haven't made any other changes to the setup.

Is the problem to do with the controller? The new controller had a jumper setting which it said to remove if using a gravity system - but I don't know enough about heating systems to know whether mine is one. Could this be the problem?

Any suggestions most welcome!

Ed

 

[ChrisR]

WHat motorised valve(s) have you got?

 

[Ed123]

Where will I find that? I am a heating newbie I'm afraid!

 

[gas4you]

How many pipes come off the boiler, 2 or 4?

Any valves should probably be in airing cupboard.

 

[Ed123]

4 pipes come off the boiler

there is a red Grundfos "valve" is this the motorised valve?

 

[kevplumb]

there is a red Grundfos "valve" is this the motorised valve?

that's the pump

4 pipes = gravity system

 

[gas4you]

If you have 4 pipes then 2 will be 22mm and 2 are 28mm? This is a gravity system. The red Grundfos 'valve' will be the pump that circulates then water around your radiators. This will be wired to your room thermostat usually. You will not be able to have heating without hot water unless there is another motorised valve near the hot water cylinder (silver looking metal box thing) and a thermostat on the h/w cylinder.

 

[Ed123]

Newbie alert!

There is a little silver Honeywell box just off the storage tank.

If the system is gravity then I just need to remove the jumper setting from the control unit?

 

[gas4you]

Yes thats it. This Honeywell box will control the temp of the hot water if there is a thermostat on the cylinder, if not it will just turn hot water on and off so you can have just heating without hot water on.

Set your timer to gravity and see if it improves things.