@muscatblue,

Hi Andy,

Welcome to the forum.  Can you give a bit more info about your system/house/usage?

• manufacturer, size
• heat loss of house 
• radiators/underfloor
• current flow temp
• room temperature
• How are you controlling the system now - thermostats? If so what sort?
• Are you using weather compensation?
• how many kWh is your ASHP is using for heating (your bills seem high for Aug-Oct)
• how much oil did you use before? 
• Is you installer MCS approved and did they do a detailed hear loss calculation?

More technical details may help later but that will do as a start.  

And how is your insulation/draught proofing? Do you really mean 1650?  

I'm sure you'll learn a lot from the forum and also make some efficiency improvements.

Kev 

Posted by: @muscatblue

Hi All,

We live in a 1650’s, 5 bed house (365m2) on the Warks/Leics border.

Both daughters are employed in the ‘Renewables Industry’ so it was a no-brainer to switch over from oil to ASHP.

However, our most recent monthly electricity bill from Bulb (😳) for mid-Oct to mid-Nov was £403 (ouch!). (£146, £143 & £122) in preceding 3 months).

In view of this latest bill, I need advice / help on how to run the system optimally.

    - How to amend the flow rate 

    - I currently isolate rooms not in daily use but

       a) Is this efficient

       b) Does it actually save any money

    - I currently turn the thermostat down overnight but again is this a false economy

I anticipate the above may be recurring themes already addressed elsewhere on the hub so apologies in advance.

Cheers,

Andy

NB. We also have an array of solar panels with FIT payments in part easing the pain of the electricity bills plus a solar i-booster.

 

 

 

Welcome to the forum.

Please have a read of the manual for your ASHP and see if it can be configured for weather compensation. If you are not certain what to look for then provide details of your system and I will have a look for you.

That’s an impressively old house!

@muscatblue, would love to see some exterior photos of the house if you're willing to share.

@derek-m 

Hi Derek,

Thanks for your interest.

We have 2 x Hitachi Yutaki RASM 6.0.

Installed by a MCS registered company based in Leicester in Jan 2020.

The system has a Weather Compensation Control function but I don't know what would be an ideal / optimal setting or how to change it on the Controller.

Any further help / advice / input would be appreciated.

Andy

@kev-m 

Hi Kev,

You may gather from my first blog that I'm a novice on the workings of ASHPs so your interest is really appreciated.

You asked for a bit more info about our system / house / usage!

Manufacturer, size : 2 x Hitachi Yutaki RASM 6.0 / Total Installed Capacity of 32.00kW / Estimated Annual Generation 41745kWh.

Heat loss of house : The MCS Certificate shows Annual Space and Water Heating Demands at 58,047 and 1,826, respectively. Also, Annual Space and Water Heating Supplied at 58,047 and 1,407, respectively.

The EPC Certificate shows Annual Space and Water Heating Demands at 44,055 and 5,524, respectively.

Radiators / underfloor : Most rooms were upgraded to larger K2 (referred to in the Handover Pack as Type 22) / There's also a convector heater in the dining room / Plus 2 x plinth heaters in the kitchen (Currently considering a wet system in this room - Can anyone recommend any competent underfloor heating contractors?).

No K3 / No underfloor.

Current flow temp : The MCS Certificate shows a Flow Temperature of 45C.

There are 2 x Hitachi Controllers in the roofspace. The digital screens show 54C for Heat on one Controller and 55C for Heat & Water on the other Controller. I don't know if the 54C for Heat is the same as the Flow Temperature? If not, how can I check this?

Room temp : As stated in my first message, I had previously isolated rooms not in use and also turned down the thermostat overnight. This led to the house being rather cold.

For the last week, I've still isolated rooms not in daily use but kept the ASHP going on a 24/7 basis at 19C / 19.5C. This has resulted in a much warmer house.

How are you controlling the system now - thermostats? : If so what sort? : On advice from the installer, I haven't touched the 2 x Hitachi Controllers in the roofspace.

Separately, I have a single Honeywell CM927 Wireless Thermostat to control the heating. I position this in the hallway at the bottom of the stairs. I adjust the temperature as required @ 0.5C at a time until the requested temperature is achieved. Also, there are TRVs on all radiators which I operate manually.

Are you using weather compensation? : The system has a Weather Compensation Control function. I don't know how to operate it / change it on the Controller to achieve an ideal / optimal setting.

How many kWh is your ASHP using for heating : I'll get back to you on this one. Am I able to get these figures from the Hitachi Controllers? If not where?

Your bills seem high for Aug-Oct : Oops, I forgot to mention we also have a hot tub!

For J-A and A-S, the hot tub was switched on continuously albeit at an average temperature of only 32C and not the usual 39C. I estimate the GBP122 and GBP143 for these 2 months would have reduced to approx. GBP52 and GBP73 but for the hot tub (say GBP70 / month).

For S-O and O-N, the hot tub was switched off.

How much oil did you use before? : I recall the oil deliveries for the old boiler were expensive but I don't have any easy comparisons on running costs as we hadn't lived permanently in the house for very long before switching to the ASHPs. We were previously overseas for many years with the house only occupied intermittently.

Is you installer MCS approved : Yes, the system was installed by a MCS registered company based in Leicester in Jan 2020.

Did your installer do a detailed heat loss calculation? : Yes, see second RFI response above.  

How is your insulation/draught proofing? : It isn't great but it's an old house! The roofspace is mostly insulated but there is a smallish mid-section that houses the cylinder and associated paraphernalia that the EPC guy suggested should be insulated.

The external walls are solid and uninsulated. (Can anyone recommend any competent insulation contractors?)

Do you really mean 1650? : Yes! The oldest part is 1652 (Interesting fact - The Third English Civil War ended the year before at the Battle of Worcester in 1651!). It has in part a timber A-frame. The most recent part is Victorian.

Any further help / advice / input would be appreciated to expand my practical knowledge and to make some efficiency improvements.

Cheers,

Andy

Posted by: @muscatblue

@derek-m 

Hi Derek,

Thanks for your interest.

We have 2 x Hitachi Yutaki RASM 6.0.

Installed by a MCS registered company based in Leicester in Jan 2020.

The system has a Weather Compensation Control function but I don't know what would be an ideal / optimal setting or how to change it on the Controller.

Any further help / advice / input would be appreciated.

Andy

Hi Andy,

So far I have not been able to locate a detailed manual on the Internet that even mentions weather compensation, so if you could point me in the right direction that would be much appreciated.

The only mention I have found, that may possibly relate to weather compensation control, is a setting labelled 'Central/Local', which mentions three types of control, Water, Air or Full. It could be possible that Water means water flow temperature control, Air means weather compensation only, and Full means weather compensation in conjunction with indoor temperature measurement. That is an educated guess, so I may be wrong.

As far as the setting of the required parameters for weather compensation are concerned, it very much depends upon the heat demand of your home, and the total output of the heat emitters. As the ambient air temperature falls, the heat loss and hence heat demand increases. To maintain a reasonably constant indoor temperature, it is necessary to increase the heat energy supply to balance the increased heat demand. The only way to accomplish this balance is by increasing the water flow temperature. So to set the slope of the weather compensation curve is it necessary to estimate the required water flow temperature at an ambient air temperature of say -5C, and at an ambient air temperature of say 15C.

So for your system to remain in balance at varying ambient air temperatures, may require a weather compensation curve that produces a water flow temperature of 50C at an ambient air temperature of -5C and a water flow temperature of 20C when the ambient air is at 15C.

If you could provide more information about the different equipment within your home it may give me a better insight as to how your system has been designed to operate.

@derek-m it has the function -

Page 54 of this manual seems to be some kind of temperature setting - http://www.solfex.co.uk/uploads/downloads/Yutaki_M_UK_Specific_Installation_Manual.pdf

The whole manual is here https://www.manualslib.com/manual/1646787/Hitachi-Yutaki-Series.html? - I think

Hi Derek,

Further to your and Batalto's messages.

The manual I was provided with by the MCS installer is headed : Freedom Heat Pumps - Air Source Heat Pump Installation & Maintenance Manual

The front cover also displays an Hitachi ASHP.

Cheers,

Andy

@batalto 

Thanks for this Batalto.

Cheers,

Andy

@muscatblue just call freedom then. They'll be able to give you the details you need

https://www.freedomhp.co.uk/