2 hours ago Steve asked ... Gilera runner 180 vxr 2001 ignition replacement?    |    Janboy68 asked ... How can I mend my KitchenAid Artisan toaster?    |    rick asked ... How can I fix my portable Zenith DVP615 DVD player? When I p?    |    Jim asked ... How can I get my scarifier to work?    |    george crawford asked ... Citroen C3 Picasso?    |    Click here to ask your question

Where is the water switch- Vailant Ecomax 824-Fault code F25?

My Vailant Ecomax is showing a fault code of F25 (water switch - low pressure) I have checked the pressure which looks fine but I cannot identify the water switch, where is it or does it have another name?
Trevor, November 2010
Top left on the pipework going to the main heat exchanger, it's round and black with a yellow face and has two wires attached.

Carefree, November 2010