Zigbee thermostatic valve HY368 - weird behaviour

Hi, I’ve recently bought HY368 and a smart gate and integrated them with tuya-app (I’ll be switching to zigbee2mqtt in HA with CC2531 soon) and I’m noticing weird behavior:

Let’s say its 18 deg in my livingroom and I set it to 20 deg, the valve will open up to ~75% and reach around 21 deg and will start SLOWLY dropping in 5% decrements, which makes the temp reach 22.5 at around 30%-60% when I lose patience and set it manually to 12 deg to close it completely. The valve shuts the pipes completely at very low value 5% or something like that. When above this its almost like completely open, so there is no difference between 30 and 60.

  1. Is there something wrong with the valves? Why do they close the valve so slowly? Can I make them close faster without resorting to hacks like setting the desired temp very low?
  2. Is it possible to read and set valve open % value directly with zigbee2mqtt from HA?

Thanks

@martijn-tinus @radekposvar @eses @MagicJohansson @Murada99 Sorry for calling you out directly guys, but I noticed here that you also have HY368, could you share your expierience with me here?

@kajman
I have had several HY’s in operation for months with no problems. They are recognized by zigbee2mqtt and I can schedule the temperature of the rooms according to the time.

What I don’t like:

  • the batteries don’t last long, about 2 months and then they have to be changed.
    When changing them, you have to rewrite the default values in zigbee2mqtt.

  • They are not easy to use manually, I find that the characters are not very clear and the sensitivity is not the best. I would have preferred buttons even if it would be less beautiful.
    Well as I don’t use them manually, it doesn’t matter much.

Otherwise, everything is fine with these HY368.

same as @Murada99

I dont care that there are no buttons because I use HA to control them. But I can understand that it can be a problemen.

Hello @kajman

I experience similar problems with the HY368.
The device seems not to be capable to keep the target temperature.
E.g. if I set the target temperature to 21°, the actual temparature varies between 20° and 22° within a 2h interval (see picture).

image

For me it seems that this device has a poorly implemented PID algorithm (See here what PID is).

I tried hard to “fix it” by playing with the device settings (The effect is smallest when setting the Hysteresis of the device to 0.5°). Also I tried to “overwrite” the PID Controller with node-red-contrib-pid. However it is not possible, because the device does not allow to force setting the valves position…

Anyway, since the valve controll is part of the devices firmware and not part of Home Assistant, Home Assistant can not do anything about that behavior…

Felix

I use them simply with one mqtt command

zigbee2mqtt/slaapkamer_trv/set/force

either open or close, according to the need.

@flixx How did you change histeresis settings? What you show is something I’d like to see at my house. I’m having the feeling as if the valves where not programmed correctly for very hot input and they close too slowly. Maybe if I change the setting it would help.

I also sometimes notice that it just disregards my temp setting and just heats up, but that’s a separate issue.

@francisp yeah, but this is just on/off. Would be great to also force 50% valve position…

@kajman Checkout the manual. It’s part of the advanced options (A8)

In short:

  • Press the big button to turn it on
  • Long press the big button for settings
  • Press + until SET blinks. Then press the big button again
  • Press the big button repeadidly until you see number 8
  • Change the value with - to 0.5
  • Wait 10 seconds. It will save automatically.

Cheers

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Hello again @kajman

after trying things out for a while, I ended now up switching from “PID” to “ON/OFF” mode with setting “AA” from the manual.

This gives me now less variance. (Only 1° and not 2° that I had with PID).


The 2 drops are open windows.

So for me this is acceptable now.

It is interesting that “ON/OFF” is not really what it seems it is, but the valve opens with 25% instead of 5% steps.

Cheers.

2 Likes

This looks very good, thanks for reporting back. I’ll try this also.