@iantelescope

While having the solar PV system installed, I would suggest that you also consider having a power diverter, such as an iBoost, EDDI or similar, to divert the excess solar generation to the immersion heater.

We have had a 4kWp solar PV system for over 10 years and on average it has reduced our electricity import by approximately 50% year on year, though we don't have an A2W heat pump running in the Winter months, so you may not achieve a 50% reduction.

The thing to remember about solar PV generation is that it varies literally second by second, which is why a power diverter can be highly useful.

A typical immersion heater is rated at 3kW, so if your solar PV system is only generating an excess of say 1kW, then heating DHW directly using the immersion heater would still be drawing 2kW from the grid. A system with a power diverter only diverts the 1kW excess to the immersion heater and does not draw any power from the grid. While it may take 3 times as long to heat the hot water cylinder, it draws no energy from the grid, so is totally free.

 @derek-m

Age Heat Pumps and Solar ?

...Many thanks for the  iBoost, EDDI  recommendation , derek. Another thing I did not know!

The "installers" who recommended the "Thermino " and the  simplification of the  Heat Pump with the removal of the Heat ex-changer, Buffer ,  Second motor and thermostat have

,predictably, now disappeared , no further contact or  E-mails.

What a cynical , self serving ,industry!

I suspect that they are looking at my correspondence with yourself @jamesPa, @derek--m and @johnmo  !

Many thanks for your advice ............

I am trying, and failing,  to find a trustworthy plumber to remove the unnecessary Heat Pump additions.

If you can, I would suggest having a solar PV system installed along with a power diverter.

With regard to your heat pump system it may be advantageous to keep the system as is for the time being,  and try various methods of optimisation (with guidance from forum members). If by next year you find that the system is still not performing adequately then certain system modifications can be considered.

The objective being to provide you with a reasonably reliable and efficient system at minimum cost.

@derek-m 

Plumber problems?

Again, many thanks derek.

My problems with plumbers , "installers" and "salesmen" simply multiply,

with  local Plumbers saying that they are "not qualified " , or registered with the Heat Pump manufacturers, and cannot , or will not,  help.!

Again , as you say, I may have to continue with my  current set up, or contemplate a large Do it yourself task.

The company recommending the "Thermino" as a replacement for my 200 l Hot water tank along with the removal of most of the unnecessary heat pump  additions  in my kitchen , still has not responded, surprise!

Solar:

Installing  Solar panels , specifically installing  batteries is presenting it's own problems, with one installer insisting, for safety and insurance reasons, that the Solar batteries be installed outside in my garden ,

whilst , the remaining three installers are recommending (cynically demanding) a loft installation.

I mistakenly,  thought that Solar was simpler to install , than Heat Pumps!

@iantelescope

I don't think that you mentioned batteries in your previous post.

While a good idea, they do involve a more detailed install than solar PV alone.

@iantelescope 

Reading your latest posts and having also followed this thread for two years, my strong recommendation, thinking mostly about your sanity, is not to embark on another project until the heat pump system is fixed.  The only exception I would make is if the only way you can get the heat pump fixed is by accepting the bundled thermio, but my concern about this offer (apart from the fact you are saying he has now disappeared) is that he is really trying to sell you a thermio not fix the heat pump.  Nevertheless if he were to write down the scope of work so you could post it for comment, I would personally consider him if there is no other option.

The problem you face is that many won't touch this because they fear ending up giving a warranty to a system that they didn't design.  I don't think there is any guarantee that this can be overcome, it depends on whether there are any reasonable traders in your area.

However your best bet imho is to draw a system diagram and write a scope of work then ask local plumbers to quote.  (Others may have another idea of the best way to get traders interested, but this is what I would do.)  I would probably also pay a visit to the local pub and ask for recommendations for flexibly minded good plumbers.  I would issue the sow to several plumbers asking for quotes.

You may get no quotes, or you may be pleasantly surprised that, because you are telling them what to do and thus taking responsibility rather than asking for advice, someone bites.

I am sure that the collective wisdom on this forum can peer review anything you write, and doing it this way gives you at least a chance of getting what you need.

If having done this, you get no satisfactory response, you are faced with either doing the DIY job or living with the system as is.  But at least if you go down this route you will know you have given it your best shot.

I found the best way to find decent trades people, is ask other good trades people for their recommendation. They won't recommend people that are rubbish to work with.

@johnmo First find your ‘good tradespeople’😉 Toodles.

Posted by: @toodles

↑

@johnmo First find your ‘good tradespeople’😉 Toodles.

You beat me to it. Was going to say the same thing. 

@jamespa @derek-m

iBoost , legionnaires switch ?

Many thanks @jamesPa & @derek-m ......I do appreciate your help and understanding.

Heat Pump strip Down :

I am searching for a competent Plumber , who will do the Heat Pump work,............................ no easy task!.

Solar Panel :

With the Heat Pump Hot Water supply not used because of the poor efficiency and high cost, I have considered feeding the Hot water tank Electric  Immerser from roof Solar panels using the iBoost Power diverter recommended by @derek-m ( again many thanks derek  , appreciated !).

iBoost, 65 C & legionnaires

I have received modified quotes for Solar Panels with an iBoost  diverter with  attached warnings  that the iBoost will prevent the water temperature from reaching 65 C , as recommended under the legionnaires directives.

Can anyone comment on the fact that the iBoost diverter will Not reach the recommended 65 C ?

Why can't I use Legionnaires , as supplied by the Heat Pump,  and otherwise use the iBoost during the summer.?

Why cannot I switch from the iBoost to the Heat Pump control ?

@jamespa 

Heat-Ex-changer upside down ?

Is it possible that my Heat -Exchanger was installed with the temperature difference , or gradient , hot to cold, in the same direction between input and output ports?

I know, I have asked this question before ,so please accept my apologies in advance  ............. a seniority deficit!

My EAC  Heat Ex-changer has no markings other than the EEC directives .

I have been here before ...............but as Oliver Cromwell did not say to the General assembly in 1651,  I do " think it possible that I could have been  wrong", maybe the heat ex changer is fitted upside down!

Posted by: @iantelescope

↑

@jamespa @derek-m

iBoost , legionnaires switch ?

 

Many thanks @jamesPa & @derek-m ......I do appreciate your help and understanding.

 

Heat Pump strip Down :

I am searching for a competent Plumber , who will do the Heat Pump work,............................ no easy task!.

 

Solar Panel :

With the Heat Pump Hot Water supply not used because of the poor efficiency and high cost, I have considered feeding the Hot water tank Electric  Immerser from roof Solar panels using the iBoost Power diverter recommended by @derek-m ( again many thanks derek  , appreciated !).

 

iBoost, 65 C & legionnaires

I have received modified quotes for Solar Panels with an iBoost  diverter with  attached warnings  that the iBoost will prevent the water temperature from reaching 65 C , as recommended under the legionnaires directives.

Can anyone comment on the fact that the iBoost diverter will Not reach the recommended 65 C ?

Why can't I use Legionnaires , as supplied by the Heat Pump,  and otherwise use the iBoost during the summer.?

Why cannot I switch from the iBoost to the Heat Pump control ?

Our hot water cylinder is at present at a temperature of 69.3C, heated solely from solar PV generation via our Immersun power diverter.

Obviously the temperature reached within your hot water cylinder will depend upon how much water is used, and how much solar PV generation is available for water heating.

Normal practice is to carry out a legionalla cycle once every 7 to 10 days, so during the Spring through to Autumn period there should not be a problem.

As the name suggests, the iBoost may indeed have a boost function, which instructs the power diverter to go into full output mode, even if it means drawing power from the grid. (iBoost owners should be able to confirm). The temperature to which the hot water cylinder is heated will be dependent upon the setting of the thermostat incorporated within the immersion heater, not by the iBoost.

In the Winter months I would assume that the hot water cylinder is heated by the heat pump, though the legionella cycle normally involves the use of the immersion heater during the final phase. If the heat pump controller cannot control the immersion heater via the iBoost for the legionella cycle, you could always perform it manually using the iBoost.