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How to set the clock on a Horstmann Electronic 7 water heater

Instructions for setting the time of day on my boiler clock.

The clocks went back last night, which means changing the clock on my appliances. One of my few remaining appliances that has a clock but no Internet connection is the timer on my boiler. It’s a new boiler (I moved in June), so I’ve never had to set the clock on it before.

It turns out it selected the correct winter/summer setting itself, but it’s drifted by twenty minutes, so I decided to set it anyway.

This is the timer on my boiler:

A control panel with some white, green and blue buttons and a small, poorly-illuminated segment display reading “10:10”.
My boiler is in a utility cupboard next to my front door. When I turn on the hot water boost, I put the post-it note on the cupboard door, so I don’t leave it on when I go out.

The name on the bottom right says “Horstmann Electronic 7”, so I did the obvious thing and googled “set clock horstmann electronic 7 boiler”.

It took me several minutes to find the answer – in the user guide for the timer – so for the sake of future!me and other Googlers, here are the instructions for setting the clock. Unless you have this exact appliance, you can stop reading.

This is a diagram showing the front of the timer:

A control panel with white, green and blue buttons and a small segment display reading “03:04”.

To set the clock:

  1. Press the green “SET” button until the left-hand indicator points to “CLOCK”. The hour should start to flash.

  2. Adjust the hour with the “MINUS”/”PLUS” buttons. It wraps around for AM/PM as appropriate.

  3. Press the blue “SELECT” button to confirm the hour. The minute should now start to flash.

  4. Adjust the minute with the “MINUS/PLUS” buttons. It wraps from 60 to 0 and vice versa.

  5. Press the blue “SELECT” button a second time to confirm the minute, and to finish.