Drayton Wiser operating questions

[ian1182]

Jonathan. That's pretty much what I'm seeing from my Wiser system. Using today as an example

05:30 , room temp = 18.5C ; target 21.0C ; boiler came on with 100% demand indicated
06:10 19.8C demand dropped to 61% and boiler started to cycle on/off as driven by Wiser with brief 5 or 10 minute burns as demand % reduces
07:10 20.7C demand hit 20% at which point boiler stopped cycling

the room temperture then remained between 20.7 & 20.9C with 20% demand but no boiler activity. I assume this meets the 21.0C target. The app only allow 0.5 granularity but Wiser internally uses 0.1C increments.

09:00 schedule dropped temp to 20C , demand now 0%
10:50 19.8C demand shown as 20% for 40 minutes, boiler ran for 5 minutes (10:50 to 10:55)
11:30 20.0C demand returns to 0%
12:10 19.9C, demand goes to 20% for 40 minutes or so. again boiler ran for around 5 minutes.

This has continued over the day with the boiler running for brief periods to maintain temp.

 

[Mister Banks]

So, what happens then? If the boiler comes on at 17C, when does it turn off, and how much overshoot above 19C do you end up with?

It turns off at 18.5c on average

 

[Mister Banks]

Jonathan. That's pretty much what I'm seeing from my Wiser system. Using today as an example

05:30 , room temp = 18.5C ; target 21.0C ; boiler came on with 100% demand indicated
06:10 19.8C demand dropped to 61% and boiler started to cycle on/off as driven by Wiser with brief 5 or 10 minute burns as demand % reduces
07:10 20.7C demand hit 20% at which point boiler stopped cycling

the room temperture then remained between 20.7 & 20.9C with 20% demand but no boiler activity. I assume this meets the 21.0C target. The app only allow 0.5 granularity but Wiser internally uses 0.1C increments.

09:00 schedule dropped temp to 20C , demand now 0%
10:50 19.8C demand shown as 20% for 40 minutes, boiler ran for 5 minutes (10:50 to 10:55)
11:30 20.0C demand returns to 0%
12:10 19.9%, demand goes to 20% for 40 minutes or so. again boiler ran for around 5 minutes.

This has continued over the day with the boiler running for brief periods to maintain temp.

How are you seeing demand? On Wiser or on your boiler?

 

[mcprinter]

It was more an observation that the room is decreasing at a faster rate than I would expect. If the room is unused, there is little point keeping it heated evenings/overnight.

Comfort mode would allow the system to target your desired temp for 9am. At the moment you are providing 1 hour of preheat which does look a bit optimistic and will only worsen going into the winter proper. That said, it's a balance between room temp, cost and perhaps happier Mrs. The advantage of comfort mode is that it takes some of the guess work out of how long it takes to get up to temperature.

Have switched Comfort and Eco on and adjusted schedules. Will see how it goes.
Happy Mrs is probably primary. Trying to ignore what the Smart Meter is telling me.
Sold her car last year and no commute, so swings and roundabouts I suppose. Also have £2K credit to burn !!!

@Mister Banks
Hope you don't mind this side discussion in your thread?
I thought it was all kind of related

 

[ian1182]

It turns off at 18.5c on average

That seems correct to me. Wiser cuts the boiler below your desired temp. The pump should run for a further 5-10 minutes and the room temp continues to rise.

 

[JonathanM]

It turns off at 18.5c on average

Then, after that, does it drop back down down to 17C, before coming on again?

 

[ian1182]

How are you seeing demand? On Wiser or on your boiler?

neither. I run a Raspberry Pi which collects data from the Hub directly.

Drayton Wiser Home Assistant Integration

Hey all, thought its about time I contributed to the HA community. Ive recently moved to the Drayton Wiser Heating platform (from the Max!Cube stuff) and Ive written a Home Assistant Component . Its probably best described as “beta” and available here...

community.home-assistant.io

That is one of the real advantages of Wiser, I believe Hive requires retrevial via the internet.

 

[ian1182]

Have switched Comfort and Eco on and adjusted schedules. Will see how it goes.
Happy Mrs is probably primary. Trying to ignore what the Smart Meter is telling me.
Sold her car last year and no commute, so swings and roundabouts I suppose. Also have £2K credit to burn !!!

@Mister Banks
Hope you don't mind this side discussion in your thread?
I thought it was all kind of related

take care with eco mode as it may cut your heating before you wish. Note the caveat I included as you may need to review when to drop the scheduled temp. Also see that I'm using a two stage reduction overnight which I find works fairly well.

 

[Mister Banks]

Then, after that, does it drop back down down to 17C, before coming on again?

There’s my problem! If my wife still feels chilly she looks at what Wiser is doing and if it hasn’t reached the set point and the boiler is off she turns the room thermostat up!

 

[JonathanM]

There’s my problem! If my wife still feels chilly she looks at what Wiser is doing and if it hasn’t reached the set point and the boiler is off she turns the room thermostat up!

So, you've not actually got that far yet!

That's a problem with TPI. There was a small study a few years ago, to see whether TPI saved money, but it actually ended up costing people more. I think they concluded it was because people didn't understand it.

 

[ian1182]

It may be worth looking at this

Drayton Wiser and Vaillant Boiler

Hi I have a cpl of question, but I'm also posting as this might help others trying to get Drayton Wiser to work properly with Vaillant (or other boilers). Setup: ecotec plus 418, S plan, installing Drayton Wiser smart controls (currently 3 rad valves). Problem: the boiler is short-cycling...

www.diynot.com

Initially I was worried my boiler was running too frequently having moved to Wiser from a "dumb" thermostat.

There is much complexity behind TPI as a quick google search will show.

 

[Mister Banks]

This evening the setpoint was at 19c and the room temperature was 19.5c, the next setpoint was 21c but the Wiser stat wouldn't call for heat until I turned it up to 21.5c

 

[ian1182]

This evening the setpoint was at 19c and the room temperature was 19.5c, the next setpoint was 21c but the Wiser stat wouldn't call for heat until I turned it up to 21.5c

not sure I understand the problem. If the current setpoint is 19C with a room temp of 19.5C why would you expect the Wiser to call for heat. A variance to that may be if comfort mode is on and the system needs to increase the room temp to achieve your next setpoint by the desired time.

Maybe if you indicate the scheduled times & required temps that would give a better idea of what I might expect to happen. On my system today I had a 20C to 21C step scheduled for 5pm and comfort mode kicked in at 4:20.

 

[Mister Banks]

1. Setpoint at 16:00 20c
2. Setpoint at 21:30 21c

The change from setpoint 1 to setpoint 2 didn't happen until I manually changed the temperature to 21.5c even though the indicated room temperature was 19.5c.

 

[Mister Banks]

Here is the schedule