Pre-winter test, Wiser thermostat delay, normal or fault?

[ericmark]

Last year, a micro switch in the motorised valve stuck, so decided worth testing all is working. Last night I noted the TRV in wife's bedroom was cold enough to bring the heating on, and thought I had heard it working, but latter clear not running, so this morning it was a trip to the flat to test all.

The Wiser wall thermostat first took it just above room temperature, the icon changed in the app, but the hub did not do a thing. So tried Nest Gen 3 thermostat next, that fired the boiler up straight away, then noted the Wiser hub show the run light, so turned Nest down, heard it click off, and boiler still running as expected, so turned the wall thermostat down, and it did switch off, so now try the TRV, noted the tick on the app then the flame on the app, but it was a few minutes before the boiler fired up.

Allowed the boiler to get warm for a few minutes, then off again and worked A1, so again tried the wall thermostat, and again quite a delay, it works, but is this delay normal and part of the Wiser algorithm, or is it a fault?

I know with refrigeration after switching off, there must be a delay before switching on again, I see no setting in the app for oil, gas, or electric, so maybe there is a delay? I also know should not turn off the oil boiler until it has fully fired up, but seemed no delay turning off.

The boiler is oil fired, but I fitted thermostats and saw no setting for oil or gas etc.

 

[Mister Banks]

Are you using a wiser trv in the bedroom or just the wiser thermostat? It is normal for there to be a delay with firing the boiler due to how wiser works, this is why you shouldn’t mix n match heating controls.

The gas or oil boiler setting is in the wiser hub and would have been configured on initial installation.

 

[ericmark]

I use TRV (Wiser) in the bedroom to fire the boiler, wall thermostat (Nest) in the hall, and wall thermostat (Wiser) in the living room, and an old bi-metal in the flat.

The gas or oil boiler setting is in the wiser hub and would have been configured on initial installation.

Ups, I installed it, don't remember any setting in the hub for oil. But going into the app, I must have done, did not remember setting this.

I started with Nest Gen 3, which is the only way for me to set the boiler to heat DHW without CH, although unlikely to use that function, in summer DHW heated with immersion heater controlled with the iboost+ so only off-peak and solar used.

It is normal for there to be a delay with firing the boiler due to how wiser works

That's good news, it is the answer I expected, nice to know that is normal.

this is why you shouldn’t mix n match heating controls.

Oh dear, I have Wiser, Nest, Energenie, Kasa, and eQ-3, the idea was that Energenie TRV heads worked with Nest, but this is not the case, had I realised I would not have bought Nest, rather a useless thermostat, but it did allow me to have a hard-wired control with only 2 wires between the hub and thermostat, I did not like the idea of relying on wireless, and batteries, not against batteries, but to lose all heating due to one set of batteries being discharged was not what I wanted, one room OK, whole house no.

So as a second system Wiser is OK, as can still use Nest, but my problem was hall cooled too slowly, so living room cold before heating kicked back in. And can't have all controlled by living room temperature as it also has an open fire.

Three sets of patio doors, and three normal doors into the house, means there is no room without alternative heating or a door to outside on the ground floors. Yes, two ground floors as built on the side of a hill.

Wiser has cured most of my problems, I am not sure about the linked TRV head, as radiator on outside wall, so colder than the room, but not run a winter yet with it, so will wait and see, and fit second wall thermostat on the Wiser if it doesn't work out.

 

[pcaouolte]

If you have the boiler type set to Oil the Wiser system will divide each hour into 3x20 minute slots (it decides when the slots start, they don't start on the hour).
A thermostat calling for heat will create a percentage demand depending on the difference between the room temperature and the desired temperature.
The boiler will switch on for the demanded percentage of the 20 minute slot.

This is a simplified version of the algorithm.

If you turn up a thermostat slightly above the current room temperature it will create only a small demand and, depending on where the system is in the 20 minute slot, this creates a delay between the change in stat temperature and the boiler firing.

If you want to minimise the delay then turn up the thermostat to at least 2 degrees above room temperature which will create a 100% demand.

 

[Mister Banks]

To add to the above post..... the flame symbol on either the Wiser app or on the Wiser thermostat only means that the thermostat is in a calling for heat mode and will not necessarily mean that the boiler should be firing as this depends on where it is within the time slot.

 

[ericmark]

It is cross my fingers time, and hope the heating now works OK. When I moved in, to turn on the heating I had to go outside down a set of steps and into the flat under the main house and plug in the pump.

So now much improved.