Evohome + HR92s not warming one room

[ndalecs]

Hi,

I am using an Evohome connected via BDR91 to a Bosch Condens 5000 WT boiler (WBC 24 S50).
The hot water goes to a water distributor then to 8 steel panel radiators, all connected directly to the distributor (star).

All 8 radiators have HR92 radiator controllers mounted and work as expected when most of the radiators require heat.
The problem comes up during the night, when most of the radiators are set to low temperature (20 degrees - not requiring any heat) and only two rooms (bedrooms) are set to a higher temperature (24 degrees).
One of the bedrooms gets to only 22 degrees, although the radiator valve is set to 100% (also set the valve to open fully in the contoller menu - checked it visually by removing the controller from the radiator).

I've been struggling to get the settings right, but Im not sure what exactly causes this issue. When checking the BRD91 it seems it's not keeping the boiler ON continuously while this radiator needs heat. It shuts down the boiler while it's heating up, then in <1 minute it requests the boiler to start but it doesn't come on immediately (probably for some safety setting of its own). This leads to this room not getting to the set temperature with only two (out of 8) radiators turned on. During the day when I turn up the heat to more radiators things get back to normal and all the rooms get to the set temperature.

Thanks!

[Richard]

Have a look at this page - https://theevohomeshop.co.uk/content/28 ... -questions

Honeywell evohome can only work with what its got and radiator size, boiler flow temp/flow have a big part to play in obtaining air temp in a room.

[ndalecs]

Thanks for the quick reply! I've been through the questiongs and also the topics here:https://ensupport.getconnected.honeywel ... AE/evohome

I dont understand why the evohome treats two rooms with different priorities.
While everything is fine with all rooms heated (the problem room is heated as well), at night, when only two rooms are set to a higher temperature, only one of them gets to the set teperature.
I have even set 29 degrees from room 2(the problem room) and it will not get over 22.5 degrees, while the other room gets to 24 or 26, or whichever temperature I choose.
Its like it has a different priority, when that room gets to set temperature, the boiler gets shut down and room 2 never goes beyond 22.5 degrees.

Although both rooms are the same size (and in the same house ), I'm not sure why evohome wouldnt turn off the radiator head for room 1 (where it has reached the desired temp) and keep the boiler on until room 2 gets warmed up as well.

[chippy419]

suspect calibration of hr92s could be part of the reason

[chippy419]

or you have a problem with flow problems round the radiators and the system needs balancing