The Efficient Home Forum

Hi, hoping someone can help with my dilemma.

I have an S plan system - 2x 2 port zone valves serving stored hot water and CH. My set up is:

Honeywell controller
2x BDR91s
Hot water temp kit sensor
12x HR91s set up into around 7 zones

I've followed the binding process to a tee, including resetting the BDR91s (15 second press, reaching the quick red flash) before attempting binding, 5 min wait before clicking the green tick, but the behaviour when controlling HW and CH from the controller is that only one BDR91 will turn on at a time (one turns off, the other turns on). Using the guided set up I've selected 2x 2 port valves, ensuing not to use either BDR as the Boiler Relay... No change in behaviour. Tried multiple set ups.

Manually controlling it (ie pressing the button on front of BDR91s will switch both on at same time). Likewise, I've now disconnected the HW BDR91 and replaced it with a Drayton controller to manage the HW separately - working just fine.

Is there something that I'm doing wrong?

I'm fairly certain you're not meant to have the zone valve on the radiator circuit as each radiator has a HR91. If you moved that to be a boiler relay, fixed the CH valve open and disconnected the boiler call from the HW valve you'd match the configuration given in the manual.

Now fixed - firmware downgrade by Honeywell (apparently the latest firmware versions are causing this issue on a standard S-Plan system. Not sure how this wasn’t tested before release as I would hazard a guess that S Plans are one of the most common setups and there’s absolutely nothing unique about the system here. Anyway, all working as it should now.

19.31 firmware had some bugs, hence it has been downgraded. 19.33 is due a release soon, which has resolved these issues and given evohome extra features.

Hi Gents

Did this get sorted as i have the same problem, ive tried so many times to get over it but nothing works.

I am running the 19.31 Version is there an update yet?

And does it automatically load?

Shane1802 wrote:Now fixed - firmware downgrade by Honeywell (apparently the latest firmware versions are causing this issue on a standard S-Plan system. Not sure how this wasn’t tested before release as I would hazard a guess that S Plans are one of the most common setups and there’s absolutely nothing unique about the system here. Anyway, all working as it should now.

You will need to contact Resideo to get this resolved - 0300 130 1299...

FYI, I had this problem and contacted Resideo support who upgraded my system to 02.00.19.33. I lost all my config in the process and had to re-bind everything but it now works as expected, both CH and DHW valves on an S Plan system open at the same time ig there's demand for both.

I noticed a new features (may be more, but only saw one so far):

In Settings - System Parameters - Stored Hot Water there's now a "Hot Water Priority" setting. The Help says to leave it disabled to have both valves active at once. Enabling it will turn off the CH valve when there's DHW demand. I left it disabled as I want both valves to open if there's demand.

Also, I noticed that after enabling the "Cold Weather Boost" feature a new option appears in Settings - System Parameters called "Cold Weather Boost Settings". I'd not noticed it before but it only appears if "Cold Weather Boost" is enabled and I've only just turned that on. You can use it to set the difference between forecast outdoor temperature and zone set point that triggers "Cold Weather Boost" which is handy.