Yes I do have that system set up.
Hi,when i select hw boost on there is no movement of the lever.
The make is a honeywell,guess it must be 20 years old now.
it says for head replacement use 40003916-001.Is that still avail.
Hi Toby,I will replace it and let you know.
Hi Toby,I followed your advice and all is well again thank you.
I think I will replace the central heating valve as well as it is the same model and a similar age