Boiler/iboost thermostat settings

lisyloo

Looking for some advice on thermostat settings.
We have solar iboost. The water cylinder is Megaflo CL250 (250 litres).

I vaguely remember people saying to set the thermostat on the boiler/cylinder lower than the iboost.
Can anyone advise on settings (we have hard water here but a water softener installed).

At the present time hubbie arises at 5:30, has a shower then obviously traditional heating will kick in. Sun comes up and we gain no benefit from the iboost as water is hot already.
I remember being advised to set the thermostats differently.

I haven't figured out where the controls are but I'm having the boiler serviced on Tuesday by friendly engineer who will help if I know the numbers.

Ta

zeupater

Hi

We have twin coil solar thermal setup and have very little need for backup DHW heating from ~March to ~November, then just a boost from the GCH which heats the top ~half of the cylinder as necessary. We set the GCH cylinder thermostat quite a bit lower (~20C) than the solar thermal and time this boost for sometime after sunset.

HTH
Z

JimLad

lisyloo wrote: »

Looking for some advice on thermostat settings.
We have solar iboost. The water cylinder is Megaflo CL250 (250 litres).

I vaguely remember people saying to set the thermostat on the boiler/cylinder lower than the iboost.
Can anyone advise on settings (we have hard water here but a water softener installed).

At the present time hubbie arises at 5:30, has a shower then obviously traditional heating will kick in. Sun comes up and we gain no benefit from the iboost as water is hot already.
I remember being advised to set the thermostats differently.

I haven't figured out where the controls are but I'm having the boiler serviced on Tuesday by friendly engineer who will help if I know the numbers.

Ta

Have you tried turning the Gas heating off completely? During the summer we find that the heat produced during the day is still in the tank the next morning as the cylinder is super insulated.

As Zeup says you could always add a Gas boost for the evening time to make sure its up to a minimum temperature that you know will last until the morning for your showers? That way if it comes on and the solar already has it at the temp then it wont actually do anything.

nigelpm

I'd add to the suggestion to try turning it off or set it very low - say 15C

Experiment with it - if it's not providing enough set it a few degrees higher until it's right.

lisyloo

Have you tried turning the Gas heating off completely?

Would be worried about not having hot water e.g. on very cloudy day.

or set it very low - say 15C

I have no idea how to set the controls.
There are no visible controls that I can see.
Is it normal to have temp controls visible? or do they normally need access with a screwdriver under a cover?

or set it very low - say 15C

This is very low for water.
Human body core is 37C, swimming pools are around 28-30 and they will cool the human body, so it sound very uncomfortable for a shower to me.
DH gets up at 5:30 and doesn't have time to hand around and will be pretty miserable if he has to have a cold shower.

I have currently set the gas water heating to come on at 7-7:30p.m. hoping this means there is some use for the iboost after morning shower.
Have had very low figures on the iboost.
That could be because there is no excess power which would be a good thing i.e. we're using a high % of the generated power.
Will need longer to tell really as it's not been great weather the past few days.
I was expecting to see higher figures on the iboost now there is no water heating in the morning.

JimLad

There should be a thermostat on the cylinder that you can easily see. The thermostat for the immersion heater is probably behind the cover of the immersion and turnable with a screwdriver.

We currently have one boost on the gas hot water set at 9pm for half an hour. This tops up the hot water if the solar boost has not been enough during the day to make sure we have hot showers in the morning.

zeupater

lisyloo wrote: »

Would be worried about not having hot water e.g. on very cloudy day.

I have no idea how to set the controls.
There are no visible controls that I can see.
Is it normal to have temp controls visible? or do they normally need access with a screwdriver under a cover?

This is very low for water.
Human body core is 37C, swimming pools are around 28-30 and they will cool the human body, so it sound very uncomfortable for a shower to me.
DH gets up at 5:30 and doesn't have time to hand around and will be pretty miserable if he has to have a cold shower.

I have currently set the gas water heating to come on at 7-7:30p.m. hoping this means there is some use for the iboost after morning shower.
Have had very low figures on the iboost.
That could be because there is no excess power which would be a good thing i.e. we're using a high % of the generated power.
Will need longer to tell really as it's not been great weather the past few days.
I was expecting to see higher figures on the iboost now there is no water heating in the morning.

Hi

Unless you're a very high DHW usage household 250l should be enough of a buffer for at least a couple of cloudy days so there's no real reason why you'd really need the gas water heating on timer over the summer .... it should just be a case of switching the DHW control from 'timed' to 'off' then switching it over to 'on' for a while if the water is a little chilly (but do remember to switch it off again afterwards!).

About water temperatures, well MrsZ is the best DHW thermostat in existence. I don't know exactly what her set-point is as it tends to vary by season, but it's somewhere around 40C ... below this and the GCH is manually fired-up to provide a boost (last done ~late February this year) ....

Regarding the proportional control not seeming to be performing too well ... is it a very recent addition or was it installed before the decent weather last month ? .... if it's been in for a while and has never performed well it's likely to be related to the setting or position of immersion coil in the cylinder (is it a main immersion at the bottom of the cylinder or a boost element fitted higher ?) ... if it's a new addition it could simply be a case of a recent shortage of photons relative to the size of the tank!

Another extremely relevant consideration is the type of shower head you have ... if it's something like the 'tropical rainstorm' one we used to have then you'll probably never be able to supply the majority of DHW from a renewable source, but that's more a personal preference choice ... we simply changed one shower head and fitted an in-line flow restrictor to another ...

HTH
Z

lisyloo

Regarding the proportional control

Solar was installed in Feb.
iBoost is using about 3KW per day going to the immersion (average over last month).
I fiddled with the controls on Sat (August 24th) to turn off morning water heating. My theory being that there was little for the solar to do after 5a.m water heating and only a single quick shower.

Everything is working fine, I was just expecting to see MORE kwh used on the iboost since Saturday, but there's been hardly anything,

The weather hasn't been good so it's too early to tell and generation has been very poor Sun/Mon.

There are no controls that I can see. A couple of grey boxes one which says "disconnect from mains before removing cover". I'm afraid that completely puts me off touching anything with a screwdriver when I don't know what I'm doing.

legoman62

As others have said on this board all you need to do is turn the cylinder stat down (usually it will be strapped to the side of the cylinder) and turn the immersion stat up.

I set a relatives up some months ago.
He is elderly, and needs hot water for 8.00am every day.

He has an iBoost too. I set his cylinder stat to 60 C and his immersion stat to 85 C.

I also set his gas heated hot water to come on once a day at 7.30am.

You could just turn the mains electricity off for a few minutes to adjust the immersion stat.

If you are unsure ask a competent person to do it.

Also bear in mind that 90 C water can burn you

I believe if you click the left button on the iBoost it will show you your daily, weekly. monthly and total savings:D

JimLad

legoman62 wrote: »

He has an iBoost too. I set his cylinder stat to 60 C and his immersion stat to 85 C.

I also set his gas heated hot water to come on once a day at 7.30am.

This is a good way of doing it as it guarantees hot water for your morning shower but as the immersion has been on higher the previous day the tank should usually still be quite warm so it wont need to actually use that much gas.

lisyloo

all you need to do is turn the cylinder stat down (usually it will be strapped to the side of the cylinder) and turn the immersion stat up

Thanks for the info - I just don't see these "stats" at all.
There really is nothing obvious and I've got down on my hands and knees and looked all around.
I guess they are under those grey box covers somewhere.

Yes - I know how to work the iboost and we have solaredge monitoring for the PV so I can see daily generation.
Unfortunately generation has been very poor the last few days so can't draw any conclusions about turning the heating off in the morning.