Advice / Suggestion for best use of Iboost

Vomityspice

Our Iboost has finally been installed and i am wondering if anyone has any useful advice as to how to maximise the benefit?

To explain; currently, my Iboost on a good generation day only divert less than 1 Kwh. I suspect this is because the tank already has hot water that is at the required temperature. Current the HW is set to come on for just 1/2 and hour in the morning and again at night time. Part of the issue may be that as most days we are only using the HW for two showers in the morning, perhaps we are not using enough water to make any difference?

My thoughts are to turn off the morning heating cycle to see if the tank will stay hot enough overnight (latent heat loss) so that the reduction in temperature is offset by solar activity during the day.

Any thoughts/ views?

[Deleted User]

Vomityspice wrote: »

Our Iboost has finally been installed and i am wondering if anyone has any useful advice as to how to maximise the benefit?

To explain; currently, my Iboost on a good generation day only divert less than 1 Kwh. I suspect this is because the tank already has hot water that is at the required temperature. Current the HW is set to come on for just 1/2 and hour in the morning and again at night time. Part of the issue may be that as most days we are only using the HW for two showers in the morning, perhaps we are not using enough water to make any difference?

My thoughts are to turn off the morning heating cycle to see if the tank will stay hot enough overnight (latent heat loss) so that the reduction in temperature is offset by solar activity during the day.

Any thoughts/ views?

Two things:


1] Ensure the thermostat for the solar/iboost is set to higher than the GCH DHW. So if there is a poor days generation the boiler will top up the heat automatically and conversely do nothing if the tank is at temp..


2] Change the timer for your GCH DHW, to the evening, so you are giving the solar pv/iboost a chance to heat the tank during the day.


We found last year that the PV heated the water almost exclusively Mar to mid Nov. Could have just turned the boiler off and do an occasional manual boost.


Cheers

zeupater

Hi

Agree with JJ ... you're currently heating the water in the morning, then just topping-up heat-loss during the day. You need to reverse this by heating the DHW by solar during the day, then top-up any shortfall after sunset (if necessary). Setting the solar thermostat higher than the GCH should help a little, but that pretty much depends on the cylinder size and relative positioning of the coil, immersion and thermostats ... but take care not to set the temperature too high if you don't have a hot water thermostatic blending valve or you will introduce a scalding risk.

HTH
Z

ChopperST

I have switched off our gas boiler now.

I know our Immersun needs to divert 11 kWh to heat our 200 litre tank to 60 degrees.

When I come home from work I simply look at the display to see how much is has diverted to the tank. If its under that margin I switch on the gas boiler on an evening.

zeupater

ChopperST wrote: »

... I know our Immersun needs to divert 11 kWh to heat our 200 litre tank to 60 degrees.

When I come home from work I simply look at the display to see how much is has diverted to the tank. If its under that margin I switch on the gas boiler on an evening.

Hi

That may be the case from a completely cold tank (mains temperature) on a daily basis ... but is that really what you're doing, or is there a residual balance from the previous day ??

For example, If 1.16kWh (usually use 1kWh rule of thumb!) raises 1tonne of water by 1C, then 11kWh will raise 200l by 47C ((11/1.16)/0.2), so with mains water at (say) ~8C you'd have 55C water in the cylinder which has been raised completely from cold supply daily ....

HTH
Z

silverwhistle

Vomityspice wrote: »

To explain; currently, my Iboost on a good generation day only divert less than 1 Kwh.

Hmm, I had an iBoost installed from the beginning and definitely get more than that! Today when the sun came out [briefly!] I was diverting more (2.k at the moment of checking), and overall I often get a hot tank, even on poor days. I've hardly used the gas for ages, and JJ's experience mirrors mine. I turn on CH and water completely manually (through choice) and haven't used gas for hot water since January, I think.

There's always residual heat in the tank, and I have an airing cupboard to exploit it.

Vomityspice

I've changed the timer last night so the proof of the pudding starts now. Let's see how well that goes!

It will be interesting to know if my hours worth of HW heating is enough, or if the latent heat loss overnight means cold water (tank is foam lagged from manufacture).

As today is looking good for generation, I'll monitor how much is diverted....

ChopperST

zeupater wrote: »

Hi

That may be the case from a completely cold tank (mains temperature) on a daily basis ... but is that really what you're doing, or is there a residual balance from the previous day ??

For example, If 1.16kWh (usually use 1kWh rule of thumb!) raises 1tonne of water by 1C, then 11kWh will raise 200l by 47C ((11/1.16)/0.2), so with mains water at (say) ~8C you'd have 55C water in the cylinder which has been raised completely from cold supply daily ....

HTH
Z

Thanks for the detailed supply.

There is no maths involved in my calculation whatsoever I'll hold my hands up to that. I am solely relying on the Immersun as being accurate. I do know however that our feed to the cylinder is at 15 degrees and not 8 as this was checked recently due to a recent fault with the Immersion.

Like I say its a very loose rule of thumb that works well for our household.

Vomityspice

So, it turns out there is now a problem with the immersion heater......

On a cold tank, when I reset the Iboost, the switch diverts 2Kwh+ and then quickly drops to nothing! So either the element has gone or the thermostat is faulty! Will get out my multi meter shortly to test each part (Although I suspect the thermostat!).

Hope it's not the heating element as this will mean having to drain the tank.... (and removing it after being encrusted for the last 12 years!)

Vomityspice

Heater element at 19.7 ohms..... Definitely looking like a dodgy thermostat now!

bchambers233

I recently had panels installed along with an iBoost and it seems to be working fine. One odd thing though, i looked at the iboost the other night at about 21:00 when the inverter had switched off and bizarrely the iboost was "Heating by Solar". This cant be right as it was dark outside.

Has anyone else had similar or any suggestions