Drayton Wiser operating questions

[harrythefurrysquid]

You definitely have the room associated with the schedule, right?

If you expand Schedule Details and then Applies to your room stat should have a green tick.
Or tap the room from the Home screen and make sure it has Follow schedule and links from Edit Schedule.

 

[Mister Banks]

You definitely have the room associated with the schedule, right?

If you expand Schedule Details and then Applies to your room stat should have a green tick.
Or tap the room from the Home screen and make sure it has Follow schedule and links from Edit Schedule.

Yes the schedule is applied to the room.

 

[ian1182]

do you have eco mode on?

If so I suspect it's saying you want 12C at 10pm and based on that the heating needs to go off much earlier. Assuming a decrease rate of 1C per hour that implies to Wiser "I better cut the heating at 2pm"!. OK, slight exaggeration but the principle applies. See my earlier comments on eco mode and the need to "play" the system.

A more realistic approach, with eco on, would be 23:00 20C and 01:00 17C. Wiser would then probably enable eco mode at 10pm to target 20C by 11pm and again soon after 11pm to achieve 17C by 1am. Do you really want your house to fall to 12C overnight. My setback (i.e. overnight temp) is 17C.

 

[harrythefurrysquid]

Just for the sake of comparison, here's some screenshots from my system in operation today.
I am running with Opentherm, Comfort Mode and Eco Mode, with Wiser TRVs on all rads.

These pics are from the "Downstairs" zone (three rooms) which I have chosen to run on the same schedule and a bit colder since I'm mostly using upstairs. These are all TRV measurements so some of the overshoot you see is probably not real - the room stat is more accurate and I use that in my study.

Rooms:
- front room (blue); double-panel rad, adjacent to next door
- hall (green); double-panel rad
- kitchen (magenta); single-panel rad

A few points of interest:
- You can see Wiser adjusting the set point time individually for each room in an attempt to try to hit the desired temp at the right time (look at the black line relative to the shaded areas)
- It's not fully able to compensate for the slower-heating kitchen (likely due to the rad) but makes a good effort overall
- It does not let the temperature sag below the set point
- You can see Eco mode being quite aggressive and effective - e.g. the Hall heating is turned down at about 17:00 at 17.5 deg and allowed to decay way before 20:00 called for in the schedule

I expect the effect of Comfort and Eco mode probably varies a bit depending on your property's insulation and heating effectiveness. I only have 6 rads for a 3 bed house and I run them at around 55 deg so it heats quite slowly, but I also just laid out for new roof insulation which is probably helping slow the heat decay so I have no issues with Eco mode.

 

[Mister Banks]

do you have eco mode on?

If so I suspect it's saying you want 12C at 10pm and based on that the heating needs to go off much earlier. Assuming a decrease rate of 1C per hour that implies to Wiser "I better cut the heating at 2pm"!. OK, slight exaggeration but the principle applies. See my earlier comments on eco mode and the need to "play" the system.

A more realistic approach, with eco on, would be 23:00 20C and 01:00 17C. Wiser would then probably enable eco mode at 10pm to target 20C by 11pm and again soon after 11pm to achieve 17C by 1am. Do you really want your house to fall to 12C overnight. My setback (i.e. overnight temp) is 17C.

I dont have eco mode on. The 12c setpoint is to be sure that the heating will never come on as the house temp never drops that low. Maybe that's whats causing the issue.

 

[harrythefurrysquid]

Post your insights graph?

FWIW I had to think a bit about how long it takes my rads to actually heat the rooms, and decided to raise the night-time temperature slightly (to 15 downstairs and 16 in the warmer rooms).

I figured Wiser can easily hold that temp with very small bursts of heat (particularly with Opentherm where the boiler seems to be happy to heat to as low as 35 degrees and pump for a bit) - whereas you can see from my charts that getting back up from say 14 degrees to 17 degrees would need the boiler running for a long time at higher temps (in my house, anyway). Same basic logic as a heat pump I guess.

 

[ian1182]

if comfort mode is also off, I would have expected the heating to kick in at 21:30 to boost the temp by a degree.

That said your schedule does not match your earlier comments. The schedule says 20C 16:00 to 21:30, 21C 21:30 to 22:00 & 12C afterwards, but you said 19C setpoint with an actual of 19.5C. I'm also not sure what Wiser would do based on a 30 minute 1 degree increase.

I have both Comfort & eco enabled. my schedule is
21C 07:15 to 09:30
20C 09:30 to 17:00
21C 17:00 to 23:00
19C 23:00 to 01:00
17C 00:30 to 07:15

Basis is occuppied house during the day.

What actually occurs setpoint wise is
05:30 21C (comfort until 07:15)
09:00 20C (eco until 09:30)
16:30 21C (comfort until 5pm)
21:00 19C (eco)
23:30 17C (eco).

In general, my lounge is close to 21C at 07:15 and 17:00 as scheduled.

Of course, although eco has brought forward the setpoint reduction to 19C at 21:00, the actual temp was 21.1C. Likewise at 11pm it was still 19.9C. Even with the nominal 17C overnight the lounge temp only dropped to 18.6C prior to the heating starting at 05:30. I have a 2 channel wiser hub (hot water + 1 heating channel) with no smart TRV's. Most of the rooms have old style TRV's. Hence just a single room within the wiser system being managed.

Perhaps you should raise the schedule values a bit and the use a hands off approach to see what happens in reality for a week or so. Then tweak a bit time or temp wise to hit your desired requirements. You may be in a phase of the system still learning the house characteristics. Whilst you may wish to fine tune on day one maybe let the system do its thing before intervening.

This is how my system has performed over the past couple of days.

 

[Mister Banks]

Thanks for all the insights, it’s really useful to read what others have done and see real world results.

I’m thinking the drop to 12c from a set point of 21c at 22:00 may be too much and Wiser may be reacting to that. My minimum temp in that location is 18c, so I will raise it to 15c and see how Wiser reacts.

 

[ian1182]

When my Wiser system was first installed I looked at how the house cooled over night and used that as a guide for the setback temperature. It was very rare for the lounge temp to fall below 17.5C even in mid-January. Hence I set 17C as the level at which the heating would come on overnight. From what I can see over winter 2021/2022 there were only a couple of occasions when the heating actually came on outside of the expected schedule. I felt it was better to maintain a steady value overnight. If your room truly dropped to 15C I suspect you might notice.

If you do enable eco later, having 15C set for 10pm will cause a major problem. The Wiser system will target that value and kill the heating around 7pm which I doubt you really want. Even with my 21->19C drop scheduled for 11pm and 19->17C at 00:30, it's fairly normal for Wiser to switch to eco 90 minutes beforehand. Of course the true room temp at 9:30pm is still around 21C, it does mean the room starts to cool afterwards. If you see the picture in my earlier note, Wiser dropped the setpoint to 17C at 21:45, raised to 19C at 23:00 and dropped again to 17C at 23:40. A scheduled 6 degree drop is likely to be more drastic.

 

[ian1182]

@ Mister Banks
You probably need to determine what you objectives are. In my case
1. House warm when I roll out of bed
2. lower temp during the day
3. slight increase in evening until retiring for the night
4. allow house to cool overnight

The first is achieved by enabling Comfort mode which should mean the house achieves the 21C target. However the last is more difficult as you don't want the heating to cut out too early, hence my two stage reduction. There may be some merit in only using Comfort mode and leaving eco disabled.

 

[Mister Banks]

@ Mister Banks
You probably need to determine what you objectives are. In my case
1. House warm when I roll out of bed
2. lower temp during the day
3. slight increase in evening until retiring for the night
4. allow house to cool overnight

The first is achieved by enabling Comfort mode which should mean the house achieves the 21C target. However the last is more difficult as you don't want the heating to cut out too early, hence my two stage reduction. There may be some merit in only using Comfort mode and leaving eco disabled.

From what I understand on comfort mode I don’t think I will be using it but instead will adjust my set point times myself to achieve what I need. Eco mode may be something I use but not before the system has settled down over the next 2 to 3 weeks. At the moment I have the room stat in the hall with the hall radiator manual TRV on max. I also have 2 Wiser TRV’s in the lounge but over the past two days their performance hasn’t been great due to the radiators being behind furniture so the temp readings are all over the place, I need a room stat for the lounge really.

 

[Mister Banks]

Sorry, hit reply to soon…….

My intention is to have 5 of the 7 downstairs radiators on Wiser TRV’s with a room stat in the lounge and/or the hall. There are 6 radiators upstairs, 4 in bedrooms and 2 in bathrooms, and I will have manual TRV’s in all bedrooms with no TRV’s in the bathrooms.

 

[Mister Banks]

Here is a reply I had from Drayton tech support re when the thermostats react to temperature changes……

“It is normally about 2C for the system to get full demand. What you are experiencing is the correct behaviour;
Whenever the setpoint temperature is above the room temperature the flame will be present/coloured. This does not mean that the boiler is on or that the system is calling for heat.
It is likely that although the flame is present the Heating LED will be off.

The heating LED is the only true tell to whether or not Wiser is calling for heat.
The relay will not energise until the PercentageDemand & PercentageDemandForItrv in a room reach 20%.

The system is designed to work in this way so that the hub is not calling for heat for only small differences, e.g. everytime the temperature drops 0.5C.”

I have asked for further clarification regarding the 20% as that seems a bit high if my understanding is correct, which it probably isn’t!

Clarification on the percentage demand below, this is from Drayton tech support.........

"The boiler reaches 100% demand when there is a 2c difference between the current temperature and the desired temperature.
20% is reached when there is a 0.4c difference between the 2.
This is then rounded up to 0.5c difference."

 

[ian1182]

That seems to match up with what I'm seeing. If the demand percentage is 70% or higher the boiler is running continuosly, less than 20% its pretty much off. Anything in between Wiser cycles the boiler on/off.

Roughly 1.5C difference is 70%, 1.0C is 50% and 0.6C is 40%. I have also seen 0% demand even when the difference is 0.3C and equally 20% demand when there is no difference. So I suspect other elements come into play for the percentage demand calculation.

 

[Mister Banks]

Is there a way to look at the settings within the hub to see how the initial setup was done, i.e gas/oil and relay/Opentherm. If I click on setup/devices/Hubr there is a "Heat Source Type" setting but it is blank, I click on the edit button and can see all the options for gas or oil etc. but when selecting "gas" the result appears on screen but then disappears a few seconds later.