Minimum valve opening value for individual TRV

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wutr
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Minimum valve opening value for individual TRV

Beitrag von wutr » 27.09.2020, 14:41

The radiators furthest from the boiler require a much larger valve opening in order to heat up vs the ones nearer the boiler. If I set the requested temperature to 30C for example they heat up fine. However for everyday use where the temperature is just below the requested temperature the valve will not open sufficiently and the radiator won't warm up. I have checked the balancing and ruled out issues there by turning off all other radiators manually.

I use a HMiP-WHS2 to control my central heating boiler. I also have a HomeMatic IP access point and I use the HomeMatic app. In the settings for the WHS2 I can set "minimum valve opening for heat demand" (or something like that), but that will apply to all valves and not just the problematic ones.

Is it at all possible to specify how far an individual valve should open as a minimum? I hope this is possible with the Access Point, but if I need a CCU for this that might be better than not being able to heat the room at all.

tomi_cc16
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Re: Minimum valve opening value for individual TRV

Beitrag von tomi_cc16 » 27.09.2020, 18:03

1. I recommend you to buy a wall thermostat e.g. WTH-2. Because than the themperature is measured by the wall thermostat and no longer at the radiator.

2. Without the wall thermostat you can set offset so when the radiator measures 21 with offset -2 = 19 degrees.
To check the radiator measured temperature you can use the https://smartha.app/

3. Yes, CCU3 has much more possibilities but also no Cloud - it works only as a local server - Solutions are available e.g. than you need Cloudmatic or VPN.
Check this:
viewtopic.php?f=49&t=41325#p410395

wutr
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Re: Minimum valve opening value for individual TRV

Beitrag von wutr » 28.09.2020, 09:58

Forgot to mention I already have the wall thermostat in that room.

I'll have a look at the smartha app too, it sounds useful for other rooms where there isn't a thermostat and the offset may need to be set.

I take it there is no way of manually setting the minimum valve opening per valve? Or only with CCU?


wutr
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Re: Minimum valve opening value for individual TRV

Beitrag von wutr » 28.09.2020, 19:42

Thank you very much. I found some properties in the 9000+ page PDF mentioning VALVE_OFFSET and was hoping that would be configurable somehow.

So far it seems like only a CCU can do that, I still need to have a look at the smartha app, as that would be much more cost effective if it can offer access to those settings.

tomi_cc16
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Re: Minimum valve opening value for individual TRV

Beitrag von tomi_cc16 » 28.09.2020, 21:36

Smartha App you can test 30 days for free but you can only read the valve data there and change the temperature. Just test it than you will know what I mean.

wutr
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Re: Minimum valve opening value for individual TRV

Beitrag von wutr » 02.10.2020, 20:24

I've used Smartha for a couple of days now and it is quite nice to see all the values including measured temperature from the radiator TRVs. Like you said I haven't been able to adjust anything related to the minimum valve opening. It sounds like I need a CCU of some kind! I'll look into raspberrymatic and piVCCU etc and see which radio module I need to get. Any tips would be appreciated (links to forum posts would be cool, German is fine).

tomi_cc16
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Re: Minimum valve opening value for individual TRV

Beitrag von tomi_cc16 » 03.10.2020, 03:00

Not sure if you saw the link - here is already a lot explained:
viewtopic.php?f=49&t=41325#p410395

I would recommend for a quick start to just buy a CCU3
but if you want to build it on your own:
- Minimum a Raspberry Pi 3
- RPI-RF-MOD (for the 868 signal)
- install RaspberrMatic

Here a step by step how to built a Raspberrymatic:
https://youtu.be/wziIL0Qezi0

Here the WebUI documentation:
viewtopic.php?f=49&t=45485

And thats it

wutr
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Re: Minimum valve opening value for individual TRV

Beitrag von wutr » 03.10.2020, 08:36

Oh I did see that but completely forgot, thanks for posting it again!

The problem persists for now, smartha shows the valve to open at 0.1% which unfortunately isn't enough. When I increase the setpoint significantly it'll open more and actually work (1% definitely does, 0.3% might also work).

It does make me wonder if smartha means 0.1% or 1%.

tomi_cc16
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Re: Minimum valve opening value for individual TRV

Beitrag von tomi_cc16 » 03.10.2020, 11:24

Hi,

yeah there was/is a mini mistake in the Defice Definitions but already corrected.

If you want to test the corrected version and you have Android- just go to the Play Store - Smartha App - scroll down and choose “want to take part at BETA”.
Install BETA

Go to “Device Definitions” and active this:
79D358BC-CAF1-4463-9648-9BFCF7E5131E.jpeg

Or wait 1-2 weeks until the update is officially released

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