Thanks Derek and Kev super impressed by your response.

In answer Derek we have 5 rads upstairs with Trv's 2 towel heaters without Trvs. All controlled by a wireless thermostat provided with the system. This is classed as zone 2. Down stairs the 7 thermostats in each room just call for heat for ufh, this is classed as zone 1.

Im going to increase by 1 deg, on each thermostat on zone 1 now to see how that goes.

Yes Kev M its counter intuitive to what we have known regards gas but more than willing to give it a try.

Posted by: @sand

Thanks Derek and Kev super impressed by your response.

In answer Derek we have 5 rads upstairs with Trv's 2 towel heaters without Trvs. All controlled by a wireless thermostat provided with the system. This is classed as zone 2. Down stairs the 7 thermostats in each room just call for heat for ufh, this is classed as zone 1.

Im going to increase by 1 deg, on each thermostat on zone 1 now to see how that goes.

Yes Kev M its counter intuitive to what we have known regards gas but more than willing to give it a try.

---

 

@sand

From you own personal experience I would recommend that in order to use the weather compensation correctly you should turn all your thermostats up to say 25ºC so they are calling for heat all the time.

And have all TVRs fully open.

Let the ASHP run using the curve for say 12 hours. After this time, if the downstairs temp is too low, notch the FTC controller display up, or if too high, notch it down and repeat the 12 hour test.

I have a similar setup as you, UFH downstairs which has 3 thermostats (but all on ASHP zone 1) and several rads upstairs with TRVs (on ASHP zone 2).

My thermostats are now purely there to tell me what the temp is, they do not control the ASHP.

Downstairs: office is usually 21ºC, hallway is usually 19ºC and living area/kitchen is usually 22ºC. The difference in temp is relative to the area of UFH piping in each area.

Upstairs is always around 20ºC.

It does sound scary I know, especially with the current cost of energy, but I too am a thrifty Yorkshireman and after almost a year of testing, experimenting with different heating regimes and settings, if someone is at home most of the time, this seems to be the most efficient way to run these systems.

But if you all go out to work, perhaps other settings/schedules might work better for you.

Great info Mark C, we are here most of the time. As we have only lived here 6 weeks its hard to get our heads around this. I just want it to be comfy not overly warm but i had visions of sitting in hat and coat all day if it was too expensive for hubby🙄 so trying to understand it get the best out of the system.

Hi @sand 

Actually I had forgotten that Mark also has a 2 zone system, so following his advice would probably be the easiest option for the present. My concern was how well balanced your system is and if all the thermostats and valves are actually connected to the controller.

The fundamental idea behind weather compensation, is that to maintain a reasonably constant temperature within your home, the heat energy supplied should closely match the total heat loss, and vary with changes in outside air temperature. Obviously, the heat loss compared to heat energy supply will vary from room to room, so you may find differences in temperature that possibly will need to be balanced, if they are found to be outside acceptable limits.

If like Mark, you can operate your system with no intervention from the thermostats and TRV's, but solely on weather compensation control then that would be much better.

Mark a question for you. Have you noticed how the FTC controller manages the opening and closing of the zone valves?

Posted by: @derek-m

Mark a question for you. Have you noticed how the FTC controller manages the opening and closing of the zone valves?

In a word, no!. Although on the FTC zone 1 is for UFH and zone 2 is for rads, I don't understand the relationship to the actual zoning throughout the property.

i.e. our UFH has 3 zones/thermostats which link to 6 manifold actuators. There is 1 synchron valve that controls flow to the manifold.

We then have 2 zones for radiators, each of which has it's own synchron valve.

This image shows ecodans kwh usage over last 4 wks. On 27th Dec changed settings to compensation curve, I know weather has been very mild, but very happy with results. 

Followed Dereks advice re comp curve figs. the settings are currently  -2 on the ftc. Upstairs a steady 19 and rooms downstairs 21 22 most of the time. On 24/7. I'm warm, husbands happy, thanks again for great advice.

Happy New Year.

So far so good then, it'll be intersting to see how the next couple of (colder) days go.  I've done the complete opposite as you and switched from weather compensation to constant flow on Christmas day as an experiment.  I'll post the results after the next couple of days but weather compensation is definitely winning so far.

@sand  and others.

How do you get these figures and graphs/diagrams etc?   I too have Ecodan 11.2KW ASHP.

Posted by: @morgan

@sand  and others.

How do you get these figures and graphs/diagrams etc?   I too have Ecodan 11.2KW ASHP.

Have you got meters installed that monitor usage and delivery? 
Known as MMSP Metering and Monitoring Service Package. Or access to the MelCloud app?

Posted by: @morgan

@sand  and others.

How do you get these figures and graphs/diagrams etc?   I too have Ecodan 11.2KW ASHP.

Have you got meters installed that monitor usage and delivery? 
Known as MMSP Metering and Monitoring Service Package. Or access to the MelCloud app?

I have the app, which i find clunky. I would've thought that a big brand name like Mitsubishi could come up with something a bit more advanced.

Posted by: @markc

Have you got meters installed that monitor usage and delivery? 
Known as MMSP Metering and Monitoring Service Package. Or access to the MelCloud app?

@markc

Hi Mark.  I don't have MMSP but I do have access to MELCloud.  Although that tells me I need a firmware update but won't update for some obscure reason. Also I understand the data from MELCloud isn't at all accurate.  For example the shown set temp' is 24C which is correct but it shows the actual room temp' as that or very close also which is inaccurate. The temp is set at 24C to keep the setting for weather comp' curve but the room temp is a comfortable 21/22C.   It makes me wonder if the other readings are accurate.