Drayton Wiser operating questions

[ian1182]

I installed my hub over 2 years ago and it would be good to understand the nuance in the various options. Looking on the Wiser Home app I see no place to set either load compensation or relay options. There are choices for heat source (gas, oil, electric or heat pump) together with Comfort & Eco modes. Presumably opentherm comes into play if the included module is wired into a suitable boiler.

 

[JonathanM]

Thanks, have seen that but i still dont understand how that is different from using the relay setting which is TPI.

From what I've just read, the EU want the official description of TPI type room thermostats to be changed to "room thermostat with on/off load compensation". This is to reflect that these thermostats sometimes use other algorithms, instead of TPI. I'm guessing the reason they have both relay and on/off load compensation is either a mistake, or is a stop gap regulatory compliance issue. This is complete speculation on my part - but I imagine they do exactly the same thing!

 

[Mister Banks]

I installed my hub over 2 years ago and it would be good to understand the nuance in the various options. Looking on the Wiser Home app I see no place to set either load compensation or relay options. There are choices for heat source (gas, oil, electric or heat pump) together with Comfort & Eco modes. Presumably opentherm comes into play if the included module is wired into a suitable boiler.

The setting is presented during the initial setup, just like the settings for gas/oil etc, and can not be changed unless you go through the setup from scratch.

I do find it strange that Drayton don't provide easy access to all available information in one place, I have found useful documents on various websites but nowhere where it is all together.

 

[Mister Banks]

From what I've just read, the EU want the official description of TPI type room thermostats to be changed to "room thermostat with on/off load compensation". This is to reflect that these thermostats sometimes use other algorithms, instead of TPI. I'm guessing the reason they have both relay and on/off load compensation is either a mistake, or is a stop gap regulatory compliance issue. This is complete speculation on my part - but I imagine they do exactly the same thing!

The tech support guy tried to explain the difference to me but it just sounded like the same thing even though he said they were different. I have emailed support so I will post here what they say.

 

[JonathanM]

The tech support guy tried to explain the difference to me but it just sounded like the same thing even though he said they were different. I have emailed support so I will post here what they say.

I'm really intrigued, so will definitely be interested in seeing their response. Maybe it's a Brexit thing? Perhaps they are just trying to keep everyone happy, so they have two options which actually do exactly the same thing, one with the new EU wording for Remainers, and the other with old wording for Leavers.

 

[Mister Banks]

I'm really intrigued, so will definitely be interested in seeing their response. Maybe it's a Brexit thing? Perhaps they are just trying to keep everyone happy, so they have two options which actually do exactly the same thing, one with the new EU wording for Remainers, and the other with old wording for Leavers.

Here is the response from tech support………

“There are now 3 options for Hub control type;

Relay - On/Off Load compensation algorithm executed with mechanical switch (called relay).

OpenTherm - Modulation algorithm executed with OpenTherm interface (no mechanical switches).

ON/OFF load compensation - On/Off Load compensation algorithm executed with OpenTherm interface (no mechanical switches).

Both OpenTherm and ON/OFF load compensation require OpenTherm compatibility and connection.

Relay is what should be used when you do not have an OpenTherm boiler.

The additional option was made available to allow OpenTherm users to chose whether they would like to use a modulation algorithm or ON/OFF load compensation.”

 

[JonathanM]

Here is the response from tech support………

Thank you. I can't see how anyone using Setup could be expected to know this!

I suppose it means if you have OT connected, but don't like the way it works, you have another option, without disconnecting it.

 

[Mister Banks]

I'm struggling to understand how these thermostats work.

The room temp is 18.5c, the stat on temp is 19c but the stat doesn't turn the boiler on until the room temp drops to about 17c. This means we start to feel a bit chilly and have to turn the temp up manually but the stat doesn't turn the boiler on until 21c.

 

[harrythefurrysquid]

the stat on temp is 19c but the stat doesn't turn the boiler on until the room temp drops to about 17c

That doesn't sound right. In my experience it will kick the boiler on more-or-less immediately if the stat is measuring less than the set point, even if it's by 0.1 degree (only shown in 0.5 degree increments on the stat / app main page). I'm using Opentherm but I don't think it's any different for relay control.

In the app, do you see a flame icon showing when you expect the stat to be calling for heat?
When the flame icon is showing, do you see the green light on the right hand side of the hub, and hear the relay click?
When the hub is showing two green lights and the flame icon is showing, does your boiler show an indicator that there is heating demand?

 

[Mister Banks]

That doesn't sound right. In my experience it will kick the boiler on more-or-less immediately if the stat is measuring less than the set point, even if it's by 0.1 degree (only shown in 0.5 degree increments on the stat / app main page). I'm using Opentherm but I don't think it's any different for relay control.

In the app, do you see a flame icon showing when you expect the stat to be calling for heat?
When the flame icon is showing, do you see the green light on the right hand side of the hub, and hear the relay click?
When the hub is showing two green lights and the flame icon is showing, does your boiler show an indicator that there is heating demand?

Opentherm will operate differently to relay operation due to the on/off sequence that relay has. According to Drayton the flame icon on the room stat will be lit during an on period if the room temp is above the set point and the only indication to be relied on is the led on the hub. That said I notice the flame icon in the app does indicate calling for heat as expected. I have emailed tech support for further clarity.

 

[harrythefurrysquid]

From my experience with the product, the flame icon will only show if the temperature is below the set point (but the displayed temp is rounded to 0.5 degrees). As you say the LED will indicate when the hub has kicked on the boiler, but I'd expect the LED to come on immediately when the flame icon is showing on the room stat or any TRV is below set temp. The LED and hub relay actuates even when running in Opentherm mode.

Does the LED come on when you expect it? If it does, then the boiler should react if it's wired correctly - but there may be a lag of a minute or so before the boiler ignites as it will have its own anti-rapid-cycling routine.

 

[ian1182]

@Mister Banks. I am also not experiencing the issues you report. For a steady state period (e.g. 6pm-10pm) my room maintains a fairly consistent temperature within 0.1C either side of the setpoint. The boiler fires up for brief 5-10 minute periods to hold the temp. This is not based on the LED or flame in the app but from automation that which gathers the system state every 5 minutes. From this I can see when Wiser enables Comfort or ECO modes or the heating channel is on/off. All I can think is your system is still learning the characteristics of your home such as how quickly the room heats/cools which are key to the smart modes to operate assuming you have enabled them. I'm not using opentherm.

 

[Mister Banks]

From my experience with the product, the flame icon will only show if the temperature is below the set point (but the displayed temp is rounded to 0.5 degrees). As you say the LED will indicate when the hub has kicked on the boiler, but I'd expect the LED to come on immediately when the flame icon is showing on the room stat or any TRV is below set temp. The LED and hub relay actuates even when running in Opentherm mode.

Does the LED come on when you expect it? If it does, then the boiler should react if it's wired correctly - but there may be a lag of a minute or so before the boiler ignites as it will have its own anti-rapid-cycling routine.

Are you looking on the thermostat or the app for the flame icon, they appear to operate slightly different and this was confirmed by Drayton techie. I am wondering though if my experience is due to how my boiler works.

 

[Mister Banks]

@Mister Banks. I am also not experiencing the issues you report. For a steady state period (e.g. 6pm-10pm) my room maintains a fairly consistent temperature within 0.1C either side of the setpoint. The boiler fires up for brief 5-10 minute periods to hold the temp. This is not based on the LED or flame in the app but from automation that which gathers the system state every 5 minutes. From this I can see when Wiser enables Comfort or ECO modes or the heating channel is on/off. All I can think is your system is still learning the characteristics of your home such as how quickly the room heats/cools which are key to the smart modes to operate assuming you have enabled them. I'm not using opentherm.

My system is literally 3 days old so it is still learning mode. To be fair I could easily just leave the system alone and let it learn but my wife is very sensitive to even small temp changes and wants the heating turned up.

 

[harrythefurrysquid]

Are you looking on the thermostat or the app for the flame icon, they appear to operate slightly different and this was confirmed by Drayton techie. I am wondering though if my experience is due to how my boiler works.

As far as I can see, the app mirrors the thermostat display.

As ian says, there's a bit of learning involved for Comfort mode and Eco mode. Comfort mode will essentially move the next scheduled set point earlier so that the room is at the desired temperature when you asked for it - so it has to estimate how long that will take based on history and outside temperature. However this is off by default. Eco mode does the same for a reduction in temperature. The room stat and app will indicate when they are in these modes.

Aside from comfort/eco modes, the behaviour is very simple: demand for heat = LED on + relay on + boiler on.