@iantelescope I’m a great believer in TOU tariffs and am currently on Cosy; this provides 3 periods per day where I can charge the Powerwall and the Thermino for 11.2 pence approx. per kWh. I allow most of my solar PV to be exported at the time of production as I receive 15 pence per kWh for it. The Eddi allows me to set the times for charging the Sunamp and I mainly use grid for this at the lower rate. I sometimes use Eddi to funnel some PV energy to the Sunamp but I still have an issue with battery drain if left to its’ own devices (talking to Myenergi about this at present.) despite having CT Clamps everywhere. Regards, Toodles.

@toodles 

 Many thanks toodles, I am at this very moment considering a quote for a Thermino fed from Solar panels with "cosy" Octopus, my energy supplier.

Roof or Garden Battery Storage?

One quote demands that the Battery storage NOT be put into my loft , for Fire safety reasons, quoting fire safety insurance documents..

Where are  your batteries , Roof or Back yard/Garden?

Posted by: @iantelescope

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Where are  your batteries , Roof or Back yard/Garden

Ours is in our plant room - this is a room in the roof, which is fully insulated with ventilation, good lighting, fire alarm

Take a read here

https://nxtgenenergy.co.uk/blog/solar-industry-update-battery-installations-in-lofts/#:~:text=The%20PAS%2063100%3A2024%2C%20issued,rather%20a%20best%20practice%20guide.

Battery chemistry has a big part to play LiFePO4 are very fire resistant, other not so good. Second hand car batteries, modified for home use, would go down the garden

@johnmo 

Roof or Garden Batteries?

Many thanks johnmo.

One of the problems I have experienced during the last two years is the continuous, often heated disputes,   between opposing supporters of Glycol or Pure water , Buffer-Volumiser Tanks or 2/4 pipe mixing tanks, HEX or not .................... or here between the Roof mounted Batteries or garden Batteries!

As with all these disputes , I, initially  don't know what to think .....or do!

However, many thanks for the information .................information , Mathematics and Arithmetic will , if I can produce a model , will settle my decision.

Posted by: @iantelescope

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Buffer-Volumiser Tanks or 2/4 pipe mixing tanks, HEX

Don't add your heat exchanger into this discussion, as it is an entirely different duty from the volumiser/buffer/HEX discussion.

Your HEX is there to transfer heat to the cylinder, in a similar way to a cylinder heating coil. You always need a heat exchanger in this cylinder heating duty.

Cylinder or Thermino (Sunamp)

Your cylinder is sized for number of likely number of people living in the property and storage temperature, and reheat time to give a suitable volume of hot water at the tap.

The hotter you store water the smaller volume you need to store, so the cylinder can become smaller.

There is a guide here on sizing and reheat times etc

https://mcdonaldwaterstorage.com/hot-water-cylinder-sizes/

Advantage of the Thermino is size and space taken up. On Buildhub there is a guy (TerryE) just skipped 2x Sunamps as there were not repairable and he installed an OSO cylinder instead, similar heat losses to the Sunamp, a little bigger.

If the PV had not suggested a Sunamp would you have been happy enough with your cylinder?

Is there an issue heating your cylinder?

Posted by: @johnmo

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Don't add your heat exchanger into this discussion, as it is an entirely different duty from the volumiser/buffer/HEX discussion.

Your HEX is there to transfer heat to the cylinder, in a similar way to a cylinder heating coil. You always need a heat exchanger in this cylinder heating duty.

From my memory earlier in the thread I don't think this is true,  I thought the system was designed with primary and secondary with the two connected via an unnecessary heat exchanger.  My memory may be faulty however and it's possible there is a second hex for the tank however that's not what I remember.

This is where a system diagram comes in so we know we are talking about the same thing!

I also recollect that the PHE is associated with the heating circuit and not the hot water cylinder. Unfortunately confusion can arise when people jump into discussions without reading the previous posts, thereby offering advice that is incorrect and creating further confusion.

Posted by: @derek-m

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Unfortunately confusion can arise when people jump into discussions without reading the previous posts, thereby offering advice that is incorrect and creating further confusion.

Have unsubscribed and will keep out of your discussion. 

Posted by: @iantelescope

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One of the problems I have experienced during the last two years is the continuous, often heated disputes,   between opposing supporters of Glycol or Pure water , Buffer-Volumiser Tanks or 2/4 pipe mixing tanks, HEX or not ...........

I have followed this thread for probably 2 years and the advice offered here, from people whose only motivation is to help, has been almost 100% consistent.  

The conflict comes between this and the people whose motivation is to sell you something.

Only you can decide which to trust!

@jamespa @dererk-m @johnmo

My Heat ex changer, HEX ?

My Heat Ex changer only isolates the Radiator, Secondary water circuit from the Primary . 

It does not connect to the Hot Water tank.

Plumber found!

Following your ,  advice @jamesPa , @johmo , I will, with trepidation,  be removing the Heat Ex changer and have finally plucked up courage and found  an excellent Plumber , well trained, and experienced  in Gas boilers, but, Very skeptical about Heat Pumps.!

The plumber has agreed to help me :

1) Remove the Heat Exchanger

2) Remove the Buffer tank.

3) Remove the second motor , second expansion vessel , second PRV.

4) Replace the Oscillating Thermostat.

5) Replace the Faulty Samsung Control board. ( the Pulse Width Modulator output does not work !)

6)  Tidy up the "beautiful" James Watt plumbing ! A visiting engineer expressed admiration for the Workmanship on the James Watt Heat Pump!

These changes will be irreparable......I will not be able to return to the Current system.

The plumber will  not accept any responsibility for the work , with all responsibility falling upon me!

I sense your reservations @derek-m .......and yes I am approaching the work with trepidation!

Posted by: @johnmo

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Posted by: @derek-m

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Unfortunately confusion can arise when people jump into discussions without reading the previous posts, thereby offering advice that is incorrect and creating further confusion.

Have unsubscribed and will keep out of your discussion. 

Please continue to contribute.

All I ask is that when people offer help that they try to make certain that the advice being provided is correct for the system in question. I often ask numerous questions so that as far as possible I have a clear picture in my mind of the system under scrutiny, so that when I do offer advice it has a much higher chance of being correct.

My many years working on highly complex systems, in numerous industries, taught me to gather as much relevant information as possible before trying to draw meaningful conclusions.

Good, and good luck.

If the plumber could also balance the radiators that would be good.  It needs to be done if not already done.

Ideally fitting one (or a pair) of anti freeze valves outside would also be a good idea to insure against freezing, but as @johnmo says this is only likely if you have long power cuts so you could omit and/or do later.

I suggest you retain the disconnected buffer tank on site for a few months in case it turns out you need to add system volume later.

The thermostat must be set a couple of degrees higher than your target room temperature so that the weather compensation, not the thermostat, is the controlling element.  Almost certainly you will, after the work is done, need to adjust the WC curve (Samsung call it water law) down a few degrees.  This is important!

Any trvs on main living rooms should also be set higher than the target so that they are open.  

Doing this should give your heat pump a chance of working as it's maker intended. 

Doubtless there will still be tweaks needed but if you report back as the heating season progresses several on the forum can help.

I need to point out once more that all advice has been given in good faith with limited information about your system, so could be wrong in some respect, but most probably isn't.