Programmable cylinder thermostat

[Ziggie]

Currently have Nest system.
Would really like to be able to have a programmable cylinder thermostat that allows different temperatures at different times.

Realise I need to have 61 degrees for a couple of hours once a week. Would want low temperature (e.g. 40 degrees at lunch time for the washing up). Would want higher temp first thing to deal with showers for the family,

Any hardware available?

 

[Chuck]

Would really like to be able to have a programmable cylinder thermostat that allows different temperatures at different times.

Think again. You are proposing to modify your system so that it breeds legionella and delivers 'hot' water that is sometimes tepid and sometimes scalding, which will cause injuries to unsuspecting users.

If you want to save energy get a better insulated tank, or improve the exisiting.

 

[Millsy 82]

Have mixer taps installed and add a bit of cold when you want it cooler.

 

[gmartine]

Thermostatic taps are available for kitchens and bathrooms.

 

[chris watkins]

How big is your cylinder & how much hot water do you use in the morning?

The likelihood is you will not be using all the higher temperature water that is floating at the top top of the cylinder, when you come to heat the water again to the lower temperature it will simple be the lower section. (unless you want to have an anti-stratification pump installed to mix it all up.
A few things which may be worth taking into account.
1. As other already stated Hot water is required to be stored at no less than 55deg C but it is normally set to 60 - 65. Any more in hard water areas & the scale starts to deposit at a much faster rate.
2. Effective dish washing normally requirers hot water at around 50+ to help with the grease.
3. Water for ablutions (washing) is around 40 degC so will be a mix of hot & cold water. Your cylinder will have been sized to take account of this so if you reduce the stored hot water temperature you will effectively be reducing the amount hot water available.

There is often a reason why hardware isn't out there & there is a good reason why Plumbers have to study for a minimum of 4 year to understand how whole systems work.

 

[oz-plumber]

If you want something that will suit your requirements, look up Rinnai Hot Water.
Gas fired continuous flow water heaters.
You can even get control pads to set the desired temperatures you want.

If you want a shower at 42C, then you press 42C into the bathroom control pad and you get 42C.
If you want 55C at kitchen sink, press 55C into kitchen control pad.

We use heaps of them over here

 

[quality]

We do this all the time with heat pumps but not to sure how to do it with a Nest controller. If the water is used regular then its not sat long enough to cause any issue especially if heated to 60 + at least once a week

 

[Basher]

To answer Ziggie’s original question - yes there is such hardware on the market. Based on having a temp. sensor on the tank that talks to a programmer.

Whether it’s a good idea, or worth the expense, I won’t comment.

There doesn’t appear to be anything you can add to Nest at the moment, so it would mean changing the system to one of these below.

Owl intuition
Owl Intuition Hot Water Tank Sensor (TBTE3H) - Smart Green Shop

Honeywell Evohome Smart Hot Water Kit
Honeywell evohome Hot Water Kit ATF500DHW

I have no experience of these, and they get mixed reviews. Just sayin...

 

[Ziggie]

Thanks to all for information and help.
I am aware of dual temperature thermostats that programme 61 degrees for one hour a week and use a set temperature for the remainder. The one I know needs a pocket in the tank which mine does not have.

There is conversations on the web about scalding and legionella.

I will research all the options provided and again thanks everyone for their input

 

[OffshoreGas]

Think again. You are proposing to modify your system so that it breeds legionella and delivers 'hot' water that is sometimes tepid and sometimes scalding, which will cause injuries to unsuspecting users.

If you want to save energy get a better insulated tank, or improve the exisiting.

But other than that its a great idea?
It could be done quite easily with a conventional control system, don't think you'll have much luck with the Nest etc "Smart" controls

 

[Brambles]

Evohome will only give you a fixed temperature up to + or - 1 degree. You can adjust it, but you cannot program it within a timer or set a “legionella” facility.

 

[Ziggie]

It may be worth noting that the maximum storage temperature of water in USA is set at 50 degrees with no increase in legionnaires. The evidence on which this was based was rejected by Joint Technical Committee for Plumbing Standards but Australia has similar guidelines.

 

[OffshoreGas]

It may be worth noting that the maximum storage temperature of water in USA is set at 50 degrees with no increase in legionnaires. The evidence on which this was based was rejected by Joint Technical Committee for Plumbing Standards but Australia has similar guidelines.

HSE guidance says water should be stored at 60C or higher, that's all a judge would care about it anyone were to suffer ill effects.

 

[chris watkins]

I would still be interested in what is driving this desire to have different temperature water at different times ??

 

[OffshoreGas]

I would still be interested in what is driving this desire to have different temperature water at different times ??

Energy saving? Which would be negligible in a well insulated tank.