I installed the resistor, activated active cooling in the hydraulic station and also in the VCR700 controller. Cooling is now also shown in the Vaillant app. I have it running on manual cooling mode with a lower flow temp limit of 18 °C and with fans under my radiators I am getting a modest but definitely very helpful effect. I am waiting for real hot weather to fully test it, but if I can shave off 2°C in the bedroom at the hottest days I’ll be very happy.
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See any “weather compensation” type behaviour with cooling, or just fixed flow temp and on/off “expanded” style? With me the on/off doesn’t work as my UFH is far to slow, so I need to control externally based on slab temp.
There does not seen to be any compensation so far. Desired flow temperature (as read through ebus) seems to be fixed at the minimum allowed flow temperature for cooling as set on the controller (18°C for me). I’m not expecting any kind of control beyond on/off anyways - with my simple radiator+ fan setup I just want 25°C instead of 28°C inside on the hottest days so I’m triggering the cooling manually. As expected, there’s quite a bit of cycling as the emitters cannot cool very efficiently. My 100 l buffer helps here quite a bit.
Sorry not the right post to be asking, but can i ask how you get your OEM dashboard to show COPs when running, space heating, and water heating?
I did try searching the forum but not sure what key words to search for…
Thanks in advance!
You need feeds that indicate when space heating and DHW are active. Either should be 0 when space heating/DHW heating is off and 1 to indicate they are on. You can then add these feeds to the My Heatpump App. I generate the inputs for these feeds using Node Red from ebus data of the three-way-valve and heat pump activity (electrical power draw).
We had our first 30°C+ day yesterday and the cooling works even better than expected. This is outdoor & living room temperature - without the cooling I would have easily hit 27°C indoors.
At the lowest, flow temperatures reach around 12°C for a short time at the beginning of a cycle. This led to minor condensation on the radiators but no dripping occurred. Due to the air flow of the installed fans, this condensate quickly evaporated when flow temperature increased.
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This is great detail. I installed the resistor and have been tracking my progress as well. Early thoughts:
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There is definitely a correlation between flow temperature and room temperature. The lower the flow the more likely it is to have an effect. I know this sounds obvious but I’m struggling to see the value (heat reduced & power consumption) when operating above the dew point. When I installed the resistor I configured the sensocomfort to operate minimum of 15 with a dew offset of 2K. At it coldest I got a 14C flow temp and in one of the rooms I could feel condensation/moisture on the skirting radiator so then turned it to 18C min flow
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I am not sure what is ‘safe’ and where the lines are with the dew point and condensation. Everyone tends to say condensation is ‘bad’ when cooling but what level of condensation are we taking about? Is there a safe level of condensation?? If no condensation forms by running above the dew point then the effect is negligible (my early data shows) and therefore not worth running the HP all day. I have skirting rads connected to the manifolds by PVC poly pipes and UFH on the ground floor
Can anyone comment on the acceptable (if any) levels of condensation?
It really depends on where the dew point is. In my test, the dew point was around 15°C and I also felt minor condensation. In the condensation was on the radiators and did not drip onto the floor. At least in my opinion this is acceptable - there won’t be any damage to the metal. Also it’s maybe 15 days in a year for me that I really need the cooling and I don’t have permanent wet spots.
Today it’s quite humid with a dew point at 20°, I’m not running the cooling in that condition as my radiators would be in the dew zone permanently and most probably start to drip.
Regarding the required temperature for cooling - yes, I need a temperature below 16°C for any noticeable effect.
just curious, but what value is the resistor on an ohm meter?
in little denmark they charge arround 40£ for the thing and if its not more than an resistor i would try and make one up myself
I think it’s 4kOhm but for some people the self-built ones did not work, so maybe there’s more to it.
I recently installed the (much cheaper German supplied) cooling resister in my Arotherm Plus and my tech configured the cooling parameters with apparent success because when set to manual and turning on “Cooling for several days” my Sensocomfort display confirms that the system is indeed in cooling mode. However it appears not to be working because, checking the master controller live monitor, it says the heat pump is in Standby mode most of the time with no cooling capacity, except when the DHW heating is needed, when the pump comes on and the cooling capacity starts registering. I can’t find anyway of getting the pump to kick in with just manual cooling/cooling for a number of days turned on. Is there some other trigger needed to force the pump to kick in for cooling only on?
In addition to cooling for several days you also have to set a schedule or “always on” mode for cooling. I do that via the app:
@David_Deakin You may also need to reduce your heating OT threshold if it’s too high.
Thanks Andre - I don’t have the app set-up and couldn’t find a specific “Always On” setting on the Sensocomfort controller, but did find the daily/weekend schedule settings and configured these for midnight to midnight every day. However, they were already set to run 06:00 to 22:30 every day, so not sure this was the cause of the heat pump not coming on? Once the wetaher warms up though, I can better test if this change had an effect.
Daniel - thanks for the suggestion. I checked and my OT threshold is set to 30 degrees C, so think that should be high enough?
I think it should be rather lower, otherwise heating will only come on above 30°C (and I think that is average over 24h).
Edit: Always on is called manual I think.
It needs to be lower, but you explaination isn’t quite right.
OT of 30C means heating won’t get disabled until outdoor temperature > 30C. If heating isn’t getting disabed at 25C outside, then it’s not going to switch from heating->cooling by itself and thats why it may only be working with “cooling for a few days”/
Thanks for the clarification - I do have it set for Manual (as against automatic) cooling. I also changed the OT Threshold down to 20C but haven’t had a warm enough day yet to test if this had an effect ):
It all seems a bit complicated for something that should be quite simple… Surely the cooling should be controlled by the temperature inside the house, not the outside, which will go up and down significantly from day to night, but inside the house (it is a modern very well insulated building) remains pretty consistent. Is there a way of setting the cooling as on manually and have it kick in based upon the room temperature on my Sensocomfort?
Today is the first warmer day we have had for a while, but even with the modified settings, set to manual cooling and “cooling for several days” switched on, it appears that the pump is only running when the DHW triggers it. During that time, in the Live Monitor, I see that it is showing a Cooling Capacity of between 4.3 and 4.6. As soon as the DHW goes off and the pump goes into standby, this cooling capacity drops to 0.
One other setting I noticed, and not sure if it is a factor with manual cooling configuration, is that the Cooling circuit MI setting is “Not Connected”. I saw reference to this being configured to Ext Temperature, but that sounded like it was only a factor if the Cooling was set to automatic?
Hi,
I just installed Vaillant arotherm+ 55/6 and tried to configure the cooling mode.
Added an homemade 4Kohm resistance on it and started to play with the settings… But couldn’t find a logic to have it running in auto mode… Untill I found this comment Enable cooling on VRC700 · Issue #438 · john30/ebusd · GitHub
I also had to toggle the VRC700 to thermostat mode to have it working.
This “averaged outside temperature” is really the problem because it’s taking so much time to go up by a warm day that it never get to the 23 or 24 like the manual suggests it. I’ve set mine start ext temp at 18 ( stop ext temp under 15 ) so the VRC700 in thermostat has faster hand on activating the cooling mode once it overpasses the summer inside temp desired.
Yesterday was a warm day and I tested with a lower summer inside temp desired setting and it started well