I’ve been going around in circles with this setting. Grant have offered conflicting information, and I’m tempted to think even they don’t know.
With the following settings, what would happen if A) the DFWT was 5 Degrees and B) 12 Degrees.
EcoNET stat set high at 24 during the day to allow the WC to do its job (average room temp 21 degrees)
Set Back at 18 Degrees
Pump Blockade Off
Open system running 6 rads (no TRVs)
Once the air temp is reached does how does the DFWT setting of 5 or 12 degrees affect the modulation. Does it reduce the flow temp by the setting or set a new parameter?
I believe it reduces the (target) flow temp, calculated from the wc curve, by dfwt degrees for every degree room temp exceeds the setpoint (presumably ignoring the hysteresis setting). Oh, and probably increases it for every degree under? Easiest way to see is look in the econet app at what lwt it is Trying for while you fiddle with the two numbers (setpoint for the room and the dfwt).
If that’s not dfwt, then it is some similar setting which has that effect. Grant (axen /plum) naming of the parameters is whacky to say the least. Probably made sense in Chinese or Polish.
edit:
nope, the one i am thinking of is room influence, so dfwt is still a mystery.
I’m still struggling to get my head around it. Here is what Grant say in the manual:
With a thermostat
· When a target air temperature is set on the assigned thermostat, the smart controller calculates flow based on ambient temperature, heating curve and current circuit air temperature.
· If ‘THERMOSTATIC PUMP BLOCKADE’ is enabled, the circuit demand will be stopped once the target air temperature set on the thermostat is reached.
· If ‘THERMOSTATIC PUMP BLOCKADE’ is not enabled, once the target air temperature is achieved the smart controller will use decrease the flow temperature target by the ‘DECREASE WATER TEMPERATURE*’* value, which is set correctly will maintain the target air temperature.
i have not played with that one, but i can confirm that with pump blockade off, the lwt is reduced (and i think increased, if the answer is negative) by ‘room influence x (thermostat target - thermostat reading)’, whether you are in fixed water temp or weather comp. Maybe you get a ‘reducing fixed water temp’ applied on top (when the stat is satisfied) I havent tried .. the room influence works for me.
Ok, tested and can confirm, when the stat is satisfied lwt is reduced by ‘reducing fixed water temp’ if pump blockade is off. in addition to the room influence calculated offset. not sure if it works for weather comp flow temps, but maybe not.
I’m using WC and the issue I’m having is the comp keeps randomly coming on throughout the night during Set Back. I’ve lowered the Set Back to 5 degrees and adjusted the DFWT throughout its range, and yet the comp still does weird things every so often. So if the comp is -as Grant - claims driven by the flow temp with pump blockade off using WC and a stat, then why is my comp coming on when the outside and inside temp is 20 degrees, the flow temp is no lower than 19 degrees at 4am and the set back is 5 degrees.
compressor will come on if return temp is 5c lower than target lwt, for defrost, for dhw heating. or every 4 hours if it is doing oil recovery. For more investigation you need to look at graph showing comressor freq, flow rate, fan speed, and the water temperatures, from which you should be able to narrow things down.
I doubt the outside temp was 20c overnight though. Was more like 2c here.
Ah,bit late to try finding the cause now then, the evidence will be long gone. if you had a delta t of 2c, that implies it had been doing something, in which case it could well be the 4 hour oil recovery cycle .. is PITA.
I guess you mean R32. l dont know, that is the old model, and does not have great reputation, defrost wise in particular. The econet smart controller may not behave the same with that model, assuming you do have the newer smart controller.
Indeed, I have the EcoNet Smart Controller. However, I don’t have an issues with the defrost function and from what I can find out there is no oil recovery mode. I just get these weird behaviours every so often during Set Back. I have a post on another forum with all the graphs, but like all my posts on this subject, it is met with silence.
Set back doesnt actually do what i believe you think it does, it just adjusts where the thermostat thinks ‘is satisfied’. With pump blockade off, the water keeps circulating and if the temp, probably the flow temp, but likely both the same anyway, gets below the target by hysteresis amount (maybe fixed to 5c, it is for the r290 model anyway) the compressor tops it up.
Now what that temp is depends on the wc curve, and also the minimum setpoint if there is one. On my system i believe the default was 24, though i raised it to 26. that means if the circulating water gets below 19c (now 21c for mine) the compressor will come on. Matters not a fig if the room is at 21, or setback to 16, or 10 .. the best the controller can do is wind down the LWT target by (however much the room is over x room influence number, maybe add decreasing fixed water temp), however i think ever the winding down may be limited by the minimum heating setpoint .. the compressor just doesn’t want to send round water at less than that (26c for me) and if it sees it going round at 5c less than the target it will restart, regardless of the room thermostat.
Will typically run for a few mins, get the flow temp up to LWT, and then sleep for an age until the circulating water cools down by 5c. If you have a buffer and a second pump is somewhat more complicated, but similar.
Indeed, I’m aware of that, hence why I made adjustments to set the point at which the flow / return temp triggers the comp. However, forget that for now, and consider this.
Seven consecutive nights the indoor and outdoor temperatures remain the same, similar for the flow and return temperature. All the settings on the controller are also the same. Mon to Thur, the HP remains off, and Fri night it comes on. I’m comparing apples with apples.
If I could put a link to another forum where this is being discussed, you could see all the graphs. It is possible, I have an intermittent fault with the flow temp sensor.
What is your (perceived) problem? If the discussion at “another forum” is relevant and complies with our code of conduct (ie. there are no offensive or abusive remarks etc), then I don’t see why you should not post a link.
I think I’ve fallen foul of becoming embroiled in a full on technical discussion, and the real issue has become lost. Hence why in my last post in the other forum I have asked this:
“Mr Smith sets his WC and Stat on his Aerona 3 R32 / Smart Controller to achieve a house temperature of circa 20 Degrees. During the night, Mr Smith prefers it cooler, so the installer tells him to have a 3 degree Set Back (17 Degrees). Mr Smith’s house maintains a minimum of 19 Degrees throughout the night. However, under the settings he was told to use by the installer, his HP comes on during the night (Set Back) heating the house up to 21 Degrees. How should Mr Smith set up his HP”
