Unvented cylinder - timer usage question

[ossocafe]

We have an unvented cylinder with a Horstmann Electronic 7 timer. The cylinder only serves a wet room which is very rarely used. The rest of the house is served by a Vaillant combi boiler.

The timer on the cylinder is set to heat up water 3 times per 24 hours, which I think it is the default. With energy costs spiralling, I would like (if possible) to reduce the time the water is heated, but also avoid creating problems with legionnaires due to lower water temperature or causing any short or long term damage to the cylinder.

Can anyone advise if there is a sensible 'minimum' setting I can use? I am happy to change the settings when we have people coming to stay (which is the only time the cylinder gets used these days).

Thanks for any advice.

 

[Mottie]

I'd say turn it off if you're not using it. Perhaps put it on once a month at a higher than usual temperature to kill off any bacteria if you're worried about it.

 

[ossocafe]

Thanks for replying!

Would that be 'safe' as far as legionnaires or damage to the unit? If it is, then what would be a good amount of time/temperature for the monthly heat-up?

 

[Mottie]

I'd say if you're not getting any legionnaires already that should be fine. Maybe a tad higher than it is and just let it reach temperature and run some off to clear out the pipes if you are concerned. If it was me, I'd just leave it off and turn it on when I needed it.

We have a place in Spain that we've had for nearly fifteen years and we only turn the immersion on when we are over there. It's used no more than a couple of months in any one year. It's always off from at least October to May. So are most of the others near us. To my knowledge, no one has ever had any problem with their cylinder or legionnaires.

 

[ossocafe]

Thanks for the advice - sounds sensible