Can we install a thermostat to this mega flow?

[u587162]

We have a 150 litre megaflow about 10 years old on our commercial property. We have to use the main spur switch to heat the water each morning for a few hours when we come in at 9am and take it off around 11am.

Is it possible to install a wired or wireless thermostat so that it can be programmed to come on around 7-10am on working days only?

We had a legionella risk assessment done a while ago and we were advised to install a Tesla immersion something or another. My plumbing company who we do the service with each year for many years have simply said no and fail to reply to several of my emails since Xmas about possible solutions so I’m trying to get the full picture from others as to what I can do.

The temp setting is behind the grey screw cover in the pic and is set by the engineer as part of each service.

 

[u587162]

 

[dilalio]

It's not a thermostat you are looking for, it's an immersion timer.
The immersion heater itself has a rod thermostat built in and controls the water temp (should be 60°c).
You can leave the power (switch) on constant and let the stat control the heating... It will interrupt power when satisfied.
Water will stay hot for a good 12hrs, inside the cylinder, if no water is drawn off, but will operate to keep the water to temp as and when it's used.

Or you can get an immersion timer.
Even one with an app if you wish.

 

[Madrab]

My plumbing company who we do the service with each year for many years have simply said no

Get rid of them. if they can't offer a solution to allow you to control your unvented HW then they don't deserve you custom nor allegiance.

I also see that the top immersion element is on a plug and not connected to anything?

Both Elements should be wired, the lower element (as suggested) through a wifi enabled (or normal) timeswitch to control it being the whole cylinder heating and the top element on a quick boost timer to provide a boost or top up capability. It will require a bit of a power supply alteration so you'll need an electrician too.

 

[CountryFan]

As Rob says, that top immersion could do with being connected as this would help with future legionella risk assessments. As per both above, you need a timer, not a thermostat to control timed periods. You can get very simple to operate mechanical timers, digital timers, WiFi and possibly even app based ones.

 

[u587162]

Madrab,
That's correct the plug is not used for anything as there is no power socket near by. I stood around whilst the cyllinder was being serviced last year and the engineer explained to me that if it ever stopped working i.e. heating water I just need to run an extension lead to the plug and it would still heat. So are you suggesting that the bottom element can instead of being connected to a spur switch, the switch can be replaced on the wall with some kind of immersion timer? If so could you please send a link to some examples? What would it typically cost to do that (based in Hertfordshire). Also is there any need for the top element to be used at all in that case (other than a boost - which has never been used)? If a socket was installed on the wall, how does one decide whether to put the timer on the plug socket or replace the spur socket one instead?

dilalio,
To clarify, are you saying I dont need a thermostat because the temperature should be set to a static 50 or 60 degrees? If it was set to a timer then surely it will not reheat again during the day back to the set temperature?



Looking at the tech stats on the other image, it says 2x 2.7kw and 2x2.3kw, what are we saying exactly, that it is currently using 2.7kwh of energy if both of the elements are being used?

Thanks.

 

[Madrab]

These guys are mad mental - I would not recommend running a 3Kw immersion element through an extension cable for any length of time - A 3Kw element on a 240V supply is a 12.5A draw, I wouldn't want to pull that amount of current through an typical extension for any length of time as that would be at the limit of most extension cables for current capacity and it would probably heat up quite quickly.

The way I would want to do it is. The lower element would be on a timed controller and that would be used to switch the main element (bottom) to come on and off, say using cheaper overnight leccy, to heat the whole cylinder to > 55deg, satisfying the legionella requirements etc. The top element would be on a separate circuit and that would be on a boost timer, so it would have a 1/2hr>1hr>2hr>4hr boost button and would just be used to top up the cylinder when needed during use. Each element has it's own thermostat so it will tick on and off to maintain the set temp.

If both elements are on it will use each elements draw x2, so - (2x3) 6Kw/h @240v or (2x27) 5.4Kw/h @230V

 

[u587162]

Just coming back to this issue, the gas shop / firm that I use to service the megaflow came back with the following response "I have spoken to the Heatrae Sadia Technical team, and have they confirmed that Smart immersion heaters aren’t compatible for use with their unit. Also, I am sorry to advise, that on further research into the possibility of time control for your stored hot water I am unable to offer a solution. This is due to the risk of Legionella that may be caused."

Bit of a crap response because the whole point in me wanting a timer was to ensure the water was sufficiently hot before we came in to work and to prevent it being left on all day.

So having read all your above comments, is it definitely possible for me to have an immersion timer fitted? Would it essentially look like one of these £30/£50 devices?

Google Search

What might the installation cost be and is it purely an electrican I need and not a gas safety registered plumber?

 

[muggles]

Yes, just an electrician and one of those will be fine

 

[Madrab]

No reason you wouldn’t be able to source and fit a smart timer, so you can connect to that rather than an actual smart immersion element itself, if you see what I mean.

 

[Razor900]

Don't get a Greenbrook timer. Have replaced no end of them.

​

Horstman stuff is pretty decent.

 

[CountryFan]

Horstman stuff is pretty decent.

Aka Secure - who make the smart meters