Horstmann Economy 7 Immersion Heating Timer

[AmyGG]

I have a Horstmann Economy 7 Immersion Heating Timer for my electric hot water tank. It hasn't been used for a long time and now the timer will not work (neither the booster or the normal 24 hour dial).

Is it easy enough to remove the cover and replace the battery (and if so, what type) or do I have to buy a new one? If a new one is required, I would be grateful for recommendations on more 'up-to-date' timers. My boiler has two elements (night rate and booster).

Also, I'm confused as to how the battery recharged. According to the installation guide, the batter is recharged as long as there is power to the box:

I don't frequently use the timer (the power button is usually set to off), I did not cut off the electricity supply. So if I were to turn the booster, the heater would still work (even though the booster timer doesn't progress through the hour). Does this count as having a constant supply of electricity to the box so that it stays recharged?

[Dave Liquorice]

I would think so, I'd expect the battery charging circuit to be connecte= d in parallel with the clock motor. The fault might be the battery but it =

could equally be the clock motor, so you could spend time and money replacing the battery and still not have a working device. Basic electronic disgnostics would help, has the battery got the correct terminal voltage, does the motor get power etc

If you don't have those skills it may be better to bite the bullet and get a new one with a digital (non-mechanical) clock they aren't particulary cheap though (approx =A350).

[AmyGG]

Both the clock and the booster clocks are not working. They used to work but I stopped using it for several months and I did not make any adjustments to the electrics during this time.

[Dave Liquorice]

Almost certainly driven from the same motor. But as installation instructions say the clock won't run until power has been applied for about 15 minutes to charge the battery it's difficult to say if the failure is due to the motor or the battery.

Either take it apart and do the basic electronics diagnosis or replace it:

=A356.95 =A356.85

For 10p I'd go for the electronic one. Constantly running mechanisms wil= l always wear out and/or break.