Product at a glance
This product is discontinued
Our 425 series of mechanical programmers are the simplest way to control hot water and central heating in the home.
The Tiara has all the capability and features of the 425 Diadem, but without the indicator lights. The Tiara is ideally suited for both gravity systems and fully pumped systems with either mid-position or zone valves.
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The above units use the same backplate as H3747 and only require simple wiring changes
|* C1727 backplate change and rewire required (economical option)