Thanks Derek, always reliable information from you. So a hydro box is different from a split system. I’ve a split Daikin system with the fan, heat exchanger, compressor outside and controls, small pressure vessel and pump inside. The hydro box adds additional capabilities to heat hot water. 

Hi Julian,

I think yours is as Kev M described a monoblock system. This is where the pipework from the ASHP into the home uses water as the heat transfer medium. In a split system the pipework uses the refrigerant gas as the transfer medium, similar to the traditional Air Conditioning system in reverse, only instead of heating air it heats water.

So basically the compressor and evaporator are in the outside unit and the condenser is in the inside unit, hence the term split system.

@derek-m

thanks very much, the link however does not seem to work for me. Takes me to a blank daikin page. I wondered and thought it was a boiler box that heated the air source heat pump water to a higher more conventional temperate for smaller radiators and those less able to retrofit. Thanks all.

Hi Phil,

It you wish to see the catalogue then just google hydrobox. There is both a Daikin and a Mitsubishi Ecodan shown in the list.

I did not know what a hydrobox was, so I was intrigued to find out.

@derek-m
I must be thick as even reading the details still don’t understand what exactly it does, it reads like either as I described, being water temp higher and or a replacement to the hot water tank. Likely neither is correct but the manufacturers use a load of sales speech without saying essentially what it is. I was hopeful for a simple explanation for a simple mind. 

Hi Phil,

I posted a simple explanation earlier this evening, but it appears to have been swallowed by one of the other titles. Try searching Derek M and see if you can find it, if not, let me know and I will send some more info.

Hydrobox seems to a term that's used inconsistently.  I can't figure out what it is from google either; even info from manufacturers is vague.

Hi Kev,

My understanding is that in a split system, the Hydrobox is the Condenser, which would be located within the outdoor unit of a monoblock ASHP system.

It is a heat exchanger, in which the hot refrigerant gas coming from the outdoor unit, is used to heat the water in the primary circuit. The primary circuit is the water that is pumped around your radiators and through the coil in your hot water tank.

If you google the following, it should lead you to the relevant manual.

HXHD-A8

Obviously, along with the heat exchanger are the controls for the system to operate correctly.

In a monoblock system there is often a buffer tank, which some may also refer to as a hydrobox, since it is filled with water. As the name suggests it acts as a 'buffer' between the ASHP and the central heating and hot water system. My understanding is that its purpose is to add a little load, so that the ASHP is not stopping and starting frequently when the heat demand of the home is quite low.

a heat loss calculation and new EPC certification should be carried out by the installer. They should replace any pipe work that is too narrow that’s a given. 

An easy method to check how effective your heating system is at transferring heat energy around your home, would be to carry out the following test. Close the valve on one of your radiators and allow it to cool down to room temperature, then with your heating system running, open the valve and time how long it takes for the radiator to come up to temperature. You could perform this test on each radiator in turn to see how effective your system is operating.

Had the first company out to quote today. Very nice chap been in business many years.

http://www.evergreenventuresltd.co.uk

Spent a good two hours here and came with the house plans he obtained and proceeded to measure each room, window and existing radiator along with our in date EPC. Spoke about model options, felt a low temp would be best and his preference is for Daikin or Panasonic split system with hydro box and a 300l tank based on bathrooms and usage. He explained he will now work it through the MCS calculator and provide a quote. I will keep everyone posted. This will help decide if it’s a this year or next year job. 

@phil3822 nice one. Of course I’m Daikin biased 😊. 300L is huge!  One prompt would be to look at www.Mixergy.co.uk and their more rapid recovery - meaning you might need a smaller tank. Early days for us but seems to be working well. 
Challenge your man as his views why Daikin over Panasonic and vice versa. Think service contract, spares, tech support, etc as well as reliability, looks, planning requirements.