My fixed 36c experiment resulted in a typical three cycle per hour as per the attached at mild ambient temps up to 10c. COP was reported as 2.69 - a number starting with a 3 still alludes me. I too am favoring auto adapt, I'll have a further play with this whilst the temps are mild.
On the subject of auto adapt mode; it seems to 'work' as it has configurable parameters, in particular the 'thermo diff adjust' that overshoots and undershoots the target temp by 5c each way by default (clearly shown in your chart - LWT target looks to be 30c, overshooting to 35c, then undershooting to 25c). I wonder why this is not configurable in the other modes (curve or fixed) the same principle must apply to these modes surely..?
My fixed 36c experiment resulted in a typical three cycle per hour as per the attached at mild ambient temps up to 10c. COP was reported as 2.69 - a number starting with a 3 still alludes me. I too am favoring auto adapt, I'll have a further play with this whilst the temps are mild.
On the subject of auto adapt mode; it seems to 'work' as it has configurable parameters, in particular the 'thermo diff adjust' that overshoots and undershoots the target temp by 5c each way by default (clearly shown in your chart - LWT target looks to be 30c, overshooting to 35c, then undershooting to 25c). I wonder why this is not configurable in the other modes (curve or fixed) the same principle must apply to these modes surely..?
I have dropped my pump speed down to 1 giving around 12 l/min, my time interval is at 10mins and overshoot is default which I think is +/-5.
I have attached my Compensation Curve which as you say shows at current ambient a LWT of around 29/30C so the overshoot/undershoot seems to be complying.
My COP figures only consider Heating Mode consumption.
All looks to be working as advertised from what you note there.
I'm going to trial:-
Thermo Diff Adjust - Upper Limit = +3 (I don't want it to overshoot too far/keep max LWT down to as sensible level as possible)
Thermo Diff Adjust - Lower Limit = -9 (give it a lot of breathing space to undershoot - rads should still have some residual heat in them when the lower limit is reached - hopefully with minimal detriment energy consumption wise on the ramp up on the next cycle)
Room Temp Control - Interval = 20mins (no real logic here, 20 mins just seems 'about right' for rads)
Flow Temp Range - Minimum Temp = 32 (I think !? this setting is intended to prevent LWT dropping to lower temps where cycling will increase. My system starts 'stalling' in the lower 30's at milder temps so I'm expecting (hoping..?) this setting will keep the LWT above the danger zone as such)
My fixed 36c experiment resulted in a typical three cycle per hour as per the attached at mild ambient temps up to 10c. COP was reported as 2.69 - a number starting with a 3 still alludes me. I too am favoring auto adapt, I'll have a further play with this whilst the temps are mild.
On the subject of auto adapt mode; it seems to 'work' as it has configurable parameters, in particular the 'thermo diff adjust' that overshoots and undershoots the target temp by 5c each way by default (clearly shown in your chart - LWT target looks to be 30c, overshooting to 35c, then undershooting to 25c). I wonder why this is not configurable in the other modes (curve or fixed) the same principle must apply to these modes surely..?
I assumed the 'thermo diff adjust' applied to fixed and curve. The manual isn't very well written but I'm not sure applying a flow temp range to auto adapt makes sense as there isn't a defined value for flow for AA; it seems to just make it up. If you look at the intro it says
"Heating operation This function allows operational setting of flow temperature range from the Ecodan and also the time interval at which the FTC collects and processes data for the autoadaptation mode."
That suggests that the interval applies to AA but the rest applies whatever the mode?
I could easily be wrong though; it's not very clear.
I assumed the 'thermo diff adjust' applied to fixed and curve. The manual isn't very well written but I'm not sure applying a flow temp range to auto adapt makes sense as there isn't a defined value for flow for AA; it seems to just make it up. If you look at the intro it says
"Heating operation This function allows operational setting of flow temperature range from the Ecodan and also the time interval at which the FTC collects and processes data for the autoadaptation mode."
That suggests that the interval applies to AA but the rest applies whatever the mode?
I could easily be wrong though; it's not very clear.
It had me confused at first. But in the FTC6 manual it quite clearly states all those settings are for room temp mode only. Also in all my tests it's had no impact when running in fixed or curve.
I assumed the 'thermo diff adjust' applied to fixed and curve. The manual isn't very well written but I'm not sure applying a flow temp range to auto adapt makes sense as there isn't a defined value for flow for AA; it seems to just make it up. If you look at the intro it says
"Heating operation This function allows operational setting of flow temperature range from the Ecodan and also the time interval at which the FTC collects and processes data for the autoadaptation mode."
That suggests that the interval applies to AA but the rest applies whatever the mode?
I could easily be wrong though; it's not very clear.
It had me confused at first. But in the FTC6 manual it quite clearly states all those settings are for room temp mode only. Also in all my tests it's had no impact when running in fixed or curve.
Yup that's clear enough. It's got me wondering what the upper and lower value actually does? It's not deviation from the set WC values because when on AA mine goes way more than 5 degrees over.
The 4:00am graph does show 2 cycles prior to hot water production. The heat demand at 4:00am will probably be slightly greater, since the external fabric of the building will have cooled. Once direct sunlight starts to hit the external areas of your home the heat demand will start to reduce, hence causing more cycling.
I remember reading that the Ecodan controller has a time setting which delays the heat pump restarting, this could be one way to extend the period between cycles, though it may cause fluctuations of the indoor air temperature.
If you have a room thermostat with a hysteresis of 1C, it may be possible to adjust the warm end setting of the WC curve to say 30C LWT at 7C outside air temperature and above. Then set the thermostat to 1C above the desired temperature. As the outside air temperature increases, and the heat demand reduces, the room temperature will start to increase until the heat pump is switched off by the thermostat, it will therefore take some time for the room temperature to fall and the thermostat to reset and restart the heat pump. This should hopefully reduce the cycling frequency.
If you have the time, you could try re-balancing your radiators, though it is not a 5 minute job.
@derekM,@gotaashp............Reporting back on previous posts, I tried Derek's ideas above but just had a constant 6 cycles an hour and a COP of about 2.3.
I have reverted back to Auto Adapt with all TRV's open except our bedroom as just can't get that balanced down at the moment and been overheating in bed.
Room Stat set at 20c most of the day, 21C evening and 19C setback overnight.
This has been giving a virtually constant hourly graph as shown attached with typically one cycle per hour and consumed 10KWh with 33kwh delivered which as a COP of 3,3 is the best I have ever recorded over the experimental exercises and one I am reasonably happy with.
I think I am going to try now on a constant set temperature of 20C and see how that performs (hopefully the weather will stall settled).
Concluding I am convinced with my system that in warm milder weather Auto Adapt is to be favoured, when we get a really cold spell I think I will try WC again when hopefully cycling may not be the issue?
Good to hear that your system operation is improving. Thanks for the update, it is always good to get feedback.
AA does appear to be the best solution in your case. I am still trying to formulate my ideas as to how the AA mode actually functions, I will no doubt post some thoughts later.
Hi everyone. It's been enlightening reading this thread as I too try to figure out how to run my ecodan efficiently. Those who give up their time to help - its really appreciated.
I also feel I am hijacking this thread somewhat but actually reading of everyone's different problems and grasping the potential solutions has been satisfying - in the end we all want to know how to get the best out of the HPs.
I acquired a property (3-bed detached bungalow (~145 sq mtr) 2 years ago and have never understood how to best set up the HP (ecodan 8.5kw). The HP provides CH only (10 rads). HW is from gas boiler. (also have 3kw solar panel system)
Energy use has been reaching almost £20/day on the recent coldest days, typically £15-£20 on the regular cold days, which has piqued my interest in understanding the HP setup better. What I have read so far has been interesting indeed. What I struggle to get a grasp of is:
1) this 'cycling' that you talk about - why is it a bad thing? i presume a cycle is when the HP kicks in to produce the desired temp & when it reaches that temp the HP stops working.
2) I keep seeing graphs? i presume these are from this 'melcloud' app? i guess i need some wireless dongle attach to my control panel somewhere to benefit from melcloud??
3) So I have the control panel (FTC5) and the wireless controller & receiver (par-wt50r-e).how can I be sure the 2 are communicating as they should be as both rarely display the same numbers (desired/actual temp) as each other.
Current setup is that (I now know thanks to reading the previous pages) we are on AA. Target temp is usually 19/20c. Have it on timer - goes off at 21h, comes on at 06h. I have only recently made this change (used to be on 24/7) in an effort to reduce consumption (££) - maybe it has had the desired effect to some degree.
I attach some pics.
Am I right in thinking my COP for 2023 so far is 2.34? my delta t shows as 2 in this image right? it was 1 this morning but also 3 moments before taking this pic. pump speed is 5 - I may reduce? whats the grey cylinder? and the filter(?) in front of it? is the filter something that needs changing? the little box with green light under the bigger box...could that be the dongle to communicate with the melcloud app?
thanks for taking the time to read. any replies to further school me would be welcomed & appreciated.
Yup that's clear enough. It's got me wondering what the upper and lower value actually does? It's not deviation from the set WC values because when on AA mine goes way more than 5 degrees over.
In terms of the thermo diff adjust, it does appear to do what it says on the tin from my testing, I've not seen it go way over or under the Upper/Lower limit values. Attached is a test from a couple of weeks ago, also look at DaveW chart from a few posts earlier as another example, it does look to be working as advertised.
I now want to add in the Minimum Temp setting in to the mix given the description noted against the Minimum temp function (below) does appear(?) to be for addressing the cycling in higher ambient temps issue we've been discussing. I'm hoping a higher minimum limit keeps my system out of the danger zone (I feel the need to try and see).
"Minimum Temp: To minimize the loss by frequent ON and OFF in mild outdoor ambient temperature seasons."
In fact.. I'm wondering.. in a system that will happily deliver low LWT in milder ambient temps without cycling too often, whether the opposite needs to happen i.e. reduce the Minimum Temp setting from the default of 30 to say 25.
My fixed 36c experiment resulted in a typical three cycle per hour as per the attached at mild ambient temps up to 10c. COP was reported as 2.69 - a number starting with a 3 still alludes me. I too am favoring auto adapt, I'll have a further play with this whilst the temps are mild.
On the subject of auto adapt mode; it seems to 'work' as it has configurable parameters, in particular the 'thermo diff adjust' that overshoots and undershoots the target temp by 5c each way by default (clearly shown in your chart - LWT target looks to be 30c, overshooting to 35c, then undershooting to 25c). I wonder why this is not configurable in the other modes (curve or fixed) the same principle must apply to these modes surely..?
I have dropped my pump speed down to 1 giving around 12 l/min, my time interval is at 10mins and overshoot is default which I think is +/-5.
I have attached my Compensation Curve which as you say shows at current ambient a LWT of around 29/30C so the overshoot/undershoot seems to be complying.
My COP figures only consider Heating Mode consumption.
It would be interesting to see the effect of increasing the 'Time Interval' from 10 minutes to 60 minutes.
My fixed 36c experiment resulted in a typical three cycle per hour as per the attached at mild ambient temps up to 10c. COP was reported as 2.69 - a number starting with a 3 still alludes me. I too am favoring auto adapt, I'll have a further play with this whilst the temps are mild.
On the subject of auto adapt mode; it seems to 'work' as it has configurable parameters, in particular the 'thermo diff adjust' that overshoots and undershoots the target temp by 5c each way by default (clearly shown in your chart - LWT target looks to be 30c, overshooting to 35c, then undershooting to 25c). I wonder why this is not configurable in the other modes (curve or fixed) the same principle must apply to these modes surely..?
I assumed the 'thermo diff adjust' applied to fixed and curve. The manual isn't very well written but I'm not sure applying a flow temp range to auto adapt makes sense as there isn't a defined value for flow for AA; it seems to just make it up. If you look at the intro it says
"Heating operation This function allows operational setting of flow temperature range from the Ecodan and also the time interval at which the FTC collects and processes data for the autoadaptation mode."
That suggests that the interval applies to AA but the rest applies whatever the mode?
I could easily be wrong though; it's not very clear.
Like you I would assume that the 'thermo diff adjust' would apply in all modes of operation.
When one thinks about what is probably happening during milder weather conditions.
The heat pump has probably pulled back to minimum output, and can't go any lower. It is producing more heat energy than that required and can be absorbed by the heat emitters, so the RWT starts to increase, which in turn pushes up the LWT. The LWT eventually hits the high limit and stops the heat pump.
How long the heat pump remains stopped will probably depend upon how quickly the LWT falls, in both fixed and WC mode. Once the LWT reaches the lower limit the heat pump restarts. The milder the weather, the lower the heat loss, so the shorter the time period to heat the LWT back up. Dependent upon where the LWT sensor is located, it may not take that much longer for the LWT to fall to the lower limit, even though the weather conditions are milder. The above may therefore lead to more frequent cycling.
In AA mode the controller is also sensing the indoor temperature, and may be taking this into account in its decision making. If, for the heat pump to be allowed to restart, it not only needs for the LWT to have reached the lower limit, but that the indoor air temperature to have fallen by a certain amount. This may therefore extend the heat pump stopped period, but should also increase the time required to heat the LWT back up. Result is less frequent cycling. Simples. 😎
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