My aroTHERM plus is misconfigured

[Bruno]

4 hours ago, J1mbo said:

Degree-minutes is used by the controller to regulate energy supply. It's not related to anything the VRC700 is doing.

Thank you

 

Further updates:

Today I bumped the day timperature to 23º. It was also a bit warmer outside so the flow temperature really didn't change much. The equipment did not cycle often (only 3 times in 8h), but the power consumption was always very low. Setpoint was at 23º, room temperature at 20,5º maximum. It seems clear that the compensation of room temperature is as I read it from the manual. I might get in touch with Vaillant to clarify this.

 

In other news I temporarily set up home assistant in a virtual machine (I want to later move it to a rpi) and sucessfully integrated multimatic. It's really easy and I have have never worked with HA before. It's as slow as the app and fails as often to fetch values ?

Unfortunately since I connected the buffer tank sensor I lost the flow temperature in the app, and it seems that in the integration as well. I need to check if there are further values which the API can fetch. And I would need to be able to change my energy meters from emoncms to HA. That will be a problem...

 

While looking for information on how to do this I came across this video

Managing heating in Home Assistant - part1 - YouTube

In the first 5 minutes the author describes a heating behavior which is precisely like mine - but on a gas boiler. Outside temperature translated to flow temperature. So I guess I'm not alone in this...

Edited January 26, 2022 by Bruno

[Bruno]

1 hour ago, Bruno said:

And I would need to be able to change my energy meters from emoncms to HA. That will be a problem...

Ah! What about that. Really easy. I wish I could kill emoncms and have the sensors directly connected to HA but that doesn't seem to be possible. However, to integrate emoncms feeds into HA works like a charm. 

 

Now I just need to know whether or not my old rpi3 can handle both emoncms+HA ?

[J1mbo]

Nice, I'm quite interested in this as it would be handy to 'hey siri turn on the hot water' when certain members of the household have used it all up.

[MikethePump]

Hi

I spotted this post while searching for Vaillant schematics for the Arotherm Plus.

(I was actually looking to see if new schematics had been released!)

I have that heat pump with a basic radiator setup, cylinder and 40l buffer tank/volumizer.

I had problems after installation with wildly varying and very high flow temperatures, heat curves not working and very poor performance.

I had undershoots and overshoots of room temperatures, all very confusing.

I am using basic system 10

It turned out that there is an issue in the controller logic (and the schematic) when using the VF1 sensor with a simple buffer/volumizer tank.

Following investigation by Vaillant It needs to be disconnected!!

The system then measures the flow temperature using the sensor in the heat pump.

The system then performs correctly using the heat curves and correct flow temperatures. (I use heat curve of about 1.0-1.1)

Performance is then hugely improved.

I have an overall CoP of 3.47 since the fix was applied (includes DHW) and got 3.67 Dec, 3.17 Jan and 3.54 so far in Feb.

Best heating Cop is 5.15 on 30th Dec, best DHW is 3.54

Overall very pleased with performance.

I have an accurate, certified MMSP monitoring system to measure inputs and outputs giving a CoP,

The Vaillant app and interface units seem to report an underperformance for me of about 18%, maybe rounding etc?

I strongly suggest that you contact Vaillant technical support, they have been great once the symptoms were identified.

The App does not show VF! temperature after the fix but it does show flow temperature as Heating Circuit 1 for me.

Hope it may help

[J1mbo]

Vaillant tech will take the easy way to get out the door within their allotted time. They also disconnected the VF1 on mine at one point. It's now installed in the buffer pocket and everything working as it should. Probably yours was a combination of curve, VRC700 citing, and radiator circuit flow rate, and possibly circulating system volume.

Edited February 15, 2022 by J1mbo

[MikethePump]

Hi J1mbo

Thanks for your comment, very interesting.

None of the things you mentioned were changed. The VF1 sensor was disconnected and the system restarted.

I have data which show the flow temperature dropping from 65-70c down to about 45c as soon as the fix was applied.

The heat pump went from running near flat out at 5kw consumption to about 2.5kw.

Everything performed as expected with no other changes.

I wonder if perhaps you have different firmware or something in the VWZ AI.interface unit.

The issue for me was that the requested flow temperature from the VRC700 was always and still is correct.

With VF! connected the interface unit/heat pump just seemed to do their own thing with the flow temp hitting up to 72c when say 47c requested.

I have to say my experience with Vaillant has been very good once I got them to recognise the issue.

I will follow this up.

Edited February 15, 2022 by MikethePump

[Dan F]

Interesting.  My VF1 works fine and ASHP flow temp is always around the max (of 3) circuit temps.  I have VRC720 though, maybe issue is with VRC700 only.

[J1mbo]

@MikethePump do you have a heat exchanger?

[MikethePump]

23 hours ago, J1mbo said:

@MikethePump do you have a heat exchanger?

Not entirely sure what you mean by that? Is that the decoupler where the glycol side is separated from the internal heating circuit?

if so no we just have a simple buffer in one side out the other!

[MikethePump]

On 15/02/2022 at 20:19, Dan F said:

Interesting.  My VF1 works fine and ASHP flow temp is always around the max (of 3) circuit temps.  I have VRC720 though, maybe issue is with VRC700 only.

That’s interesting. I contacted a senior guy at Vaillant yesterday who confirmed that in my configuration the VF1 sensor does need to be disconnected to avoid the problems I experienced. It may be that it only relates to my particular configuration?

[Dan F]

21 minutes ago, MikethePump said:

That’s interesting. I contacted a senior guy at Vaillant yesterday who confirmed that in my configuration the VF1 sensor does need to be disconnected to avoid the problems I experienced. It may be that it only relates to my particular configuration?

It could be an issue with VRC700 (I have VRC720)

 

On 15/02/2022 at 11:01, MikethePump said:

I am using basic system 10

Have you checked this with Vailant?  According to manual basic system 10 is for systems with HEX.  Basic system 8 is for systems with HEX.  Scroll up to see the screenshots from the manual.

Edited February 16, 2022 by Dan F

[MikethePump]

1 hour ago, Dan F said:

It could be an issue with VRC700 (I have VRC720)

 

Have you checked this with Vailant?  According to manual basic system 10 is for systems with HEX.  Basic system 8 is for systems with HEX.  Scroll up to see the screenshots from the manual.

well yes I have but we are in the depths of Vaillant schematics here. I believe from the manual below we are section 1 Buffer only. This does state basic system diagram code 10. However section 3 Hex only also shows code 10. Confusing!
https://www.vaillant.co.uk/downloads/aproducts/renewables-1/arotherm-plus/all-schematics-wiring-notes-1799366.pdf

[Dan F]

27 minutes ago, MikethePump said:

well yes I have but we are in the depths of Vaillant schematics here. I believe from the manual below we are section 1 Buffer only. This does state basic system diagram code 10. However section 3 Hex only also shows code 10. Confusing!
https://www.vaillant.co.uk/downloads/aproducts/renewables-1/arotherm-plus/all-schematics-wiring-notes-1799366.pdf

 

Yes, it conflicts with schematic I know (could be an error?).  I'm running "8" and everything works, I haven't tried 10.

Edited February 16, 2022 by Dan F

[MikethePump]

34 minutes ago, Dan F said:

 

Yes, it conflicts with schematic I know (could be an error?).  I'm running "8" and everything works, I haven't tried 10.

Dan F do you have buffer only or do you have the Hex module? Vaillant did suggest that in Europe they more often had Hex modules and that VF1 worked in those environments.

[Dan F]

33 minutes ago, MikethePump said:

Dan F do you have buffer only or do you have the Hex module? Vaillant did suggest that in Europe they more often had Hex modules and that VF1 worked in those environments.

Buffer only.   No glycol in system, got these instead: https://www.altecnic.co.uk/206.  Means no effiency losss from using either glycol or HEX.

Edited February 16, 2022 by Dan F

[MikethePump]

11 hours ago, Dan F said:

Buffer only.   No glycol in system, got these instead: https://www.altecnic.co.uk/206.  Means no effiency losss from using either glycol or HEX.

More and more interesting. How did you arrive at basic system 08, did Vaillant or the installer set that for you or have you done your own research and configuration?

[Dan F]

1 hour ago, MikethePump said:

More and more interesting. How did you arrive at basic system 08, did Vaillant or the installer set that for you or have you done your own research and configuration?

The installer set it based on reading manual(s).  I had independently studied the manuals and come to the same concluion though. 

[J1mbo]

Vaillant should have provided a schematic for your specific install and that will state the type code.

 

Note that there is also a heat exchanger present Boolean in the heat pump interface setup (default setup passcode 17 btw).

 

The VRC flow temp target would be the VF1, since that is essentially the radiator circuit flow temp. The heat pump flow temp target will vary and be higher due to the thermal step across the buffer which will vary with load and flow rates. The heat pump side will usually run at full pump speed. The radiator side pump speed should be sufficient to achieve about 5K delta across the flow and return when everything is stable.

[Dan F]

8 minutes ago, J1mbo said:

Vaillant should have provided a schematic for your specific install and that will state the type code.

Not in our case.  Our installer basically did their own thing, and then modified it when I requested mixed circuits.  We get 7yr guarantee because our installer is Vailant-registered, but Vaillant haven't been involved at all.

 

8 minutes ago, J1mbo said:

The radiator side pump speed should be sufficient to achieve about 5K delta across the flow and return when everything is stable.

This come from any Vaillant info, or is just best practice that you are aware of?     Our installer wanted to try to match emitter flow rates with ASHP flow rate as much as possible, not clear on reasoning for this though.

 

 

Edited February 17, 2022 by Dan F

[J1mbo]

The 5K dT is because this provides an average surface temperature only 2.5K less than the flow temp so minimising flow temperature required.

 

The reason for balancing flow rates is to minimise the temperature gradient across the buffer. But the heat pump water pump is running a short loop in 28mm  pipe and will likely be achieving 2050lph (the flow rate is shown on the heat pump interface btw). The radiator circuit is likely a smaller pump through much more resistance so will probably always be lower.

Edited February 18, 2022 by J1mbo

[m0deller]

I have an aerotherm+ 12kW with 3 circuits, HEX and 45l buffer. 

The VF1 is connected into the top pocket of the buffer. It's using circuit 10. Expanded room temperature. 

The flow tracks the demanded flows (I'm using ebusd to monitor) 

[Dan F]

2 hours ago, m0deller said:

I have an aerotherm+ 12kW with 3 circuits

Do you have all circuits running at same temperature, or do you have them mixed?

 

2 hours ago, m0deller said:

The VF1 is connected into the top pocket of the buffer. It's using circuit 10. Expanded room temperature. 

I'm using "active" room temperature mod.  I'm unclear of pros/cons of "active vs. expanded".  Have you seen the issues mentioned regarding VF1?  Do you think these impact you? 

 

2 hours ago, m0deller said:

The flow tracks the demanded flows (I'm using ebusd to monitor) 

Very interesting.  Can I ask how you are doing this?  Raspberry pi with USB ebus adapter?  Any specific software to decode proprietary ebus stuff? 

 

[m0deller]

1 hour ago, Dan F said:

Do you have all circuits running at same temperature, or do you have them mixed?

 

I'm using "active" room temperature mod.  I'm unclear of pros/cons of "active vs. expanded".  Have you seen the issues mentioned regarding VF1?  Do you think these impact you? 

 

Very interesting.  Can I ask how you are doing this?  Raspberry pi with USB ebus adapter?  Any specific software to decode proprietary ebus stuff? 

 

Yes, all circuits run at same temperature. The UFH is directly couple - no blend valve

I've not tried Active , so can't comment vs Expanded

I run ebusd on a pi using the ebus adapter (Wemos D1) WiFi , with a circuit I built myself from here (whilst I wait for ebus Adapter 3) . This is linked to emoncms which is where I do the graphing and trending. Using emon I can measure the power consumption from the ASHP and fuse this with the environmental yield from ebus to generate a rolling CoP. 

Because I run the ASHP harder overnight (when it's typically colder) , my CoP suffers .. but I'm paying 5.5p/kWh (for the time being ? )

 

 

 

[J1mbo]

The COP is (Yield+Consumption)/Consumption roughly - more like 3.7

[m0deller]

J1mbo .. interesting and thanks. I did wonder why the working figure was higher .. never occurred to me that the yield didn't include the power used. Every day a learning day!