I have a Honeywell ST7100 central and hot water controller. It has worked fine for years, and still works fine if I select only hot water, or only heating.
But if I select heating and hot water then a loud rattling/vibrating noise instantly begins. Switching back to either ch or water stops the noise.
If I press against the cover of the st7100 controller the noise becomes louder or quiter depending on how I press.
Any ideas what could be wrong?
Thanks Martin
But if I select heating and hot water then a loud rattling/vibrating noise instantly begins. Switching back to either ch or water stops the noise.
If I press against the cover of the st7100 controller the noise becomes louder or quiter depending on how I press.
Any ideas what could be wrong?
Thanks Martin