The Efficient Home Forum

Hello all,

I need some help resolving two small "issues" with my evohome setup. First off, I am not a heating / evohome expert so apologies if I don't explain things well, use the wrong terminology or miss something out.

We initially put in an evohome setup in 2016 when refurbing our home, consisting of the following:
- Viessmann Vitodens 100-W wall-mounted gas condensing boiler
- OSO Super S unvented water storage
- 6 zones (5 zones with one HR92, and 1 large zone with two HR92)
- UFH controlled by a BRD91 wired to a room controller (Hortsmann, I think)
- 3 bathroom radiators without valves

Subsequent to this initial setup the following modifications were made:
- The hall had its second radiator added to the zone after its dodgy leaky valve was replaced, allowing an HR92 to be fitted
- An extra zone was added after I had the 2nd reception room rad valve replaced at the same time as above, allowing an HR92 to be fitted
- The wired room thermostat controlling the UFH "exploded", so I got a plumber to replace it with a T87RF which (I assume) was bound to the BRD91. I was hoping to add this as a zone in the evohome setup but couldn't get it working at the time. More on that...
- The room containing the two HR92 was physically split into two separate rooms (bedroom & office), so an extra zone was created. I realised some time later that one HR92 was acting as the temp reader for both zones, so I had to unbind/bind one of the HR92s to fix that.

All was fine and dandy, but after having "Smart Meters" installed and the utility costs increasing (highlighted by the scary daily costs displayed on the HUD) I wanted to try to minimise our bills, so did the following:
- I updated all the zone schedules so that the set points for unoccupied rooms during the day, and night time in all zones except the UFH zone, were changed from 16C to 12C. We keep all doors closed whenever possible to minimise cross-zone heating confusion.
- I worked out how to bind the T87RF to the evohome controller so the UFH room appears as an extra zone.

This leads me to the two issues:

1) I noticed before going to bed that the radiator indicator icon on the boiler is on, but the UFH is not on and the temp in all other zones is higher than the set point (12C). So, the boiler is pushing water to CH but nothing is (should be) calling for heat? Why is that, and how can I test or try to fix this?

2) Since binding the T87RF to the evohome I've noticed that it and the BRD91 are not "in sync", i.e. the UFH is on but the heating indicator on the T87RF isn't, the room temp is more variable (either too hot or too cold). The zone on the evohome controller shows a HEATING TYPE of ZONE VALVE, which I understand is correct. Do I need to bind the BRD91 to the evohome as well, or is what I'm (trying) doing not possible?

I have attached a photo of the cupboard (in the downstairs loo) containing the boiler etc. The other side of the cupboard/wall is the kitchen/diner zone heated by the UFH.

Thanks in advance for any questions / help you can provide.

Phil

For your issue 1), I would check what the demands of each zone are, and see what, if anything, is calling for heat. (Long press on settings, and then system summary.)

lloyd wrote:For your issue 1), I would check what the demands of each zone are, and see what, if anything, is calling for heat. (Long press on settings, and then system summary.)

Thanks Lloyd, I'll check that the next time.

lloyd wrote:For your issue 1), I would check what the demands of each zone are, and see what, if anything, is calling for heat. (Long press on settings, and then system summary.)

I checked this last night before going to bed and all rads showed 0% but "BOILER CONTROL" and "KITCHEN" zones showed 78%. I'm not sure what that means exactly...any ideas? Is this due to my binding the T87RF to the evohome controller?

Phil

There have been some interesting developments...

The BDR91 and T87RF were defo out of sync, such that the UFH was not coming on at all. So, yesterday I cleared the binding on the BDR91 and then bound it to the "Kitchen" zone, which seemed to do something as the UFH came on. Thinking/hoping that might've fixed it, I left it to see what would happen.

When I got up this morning the UFH had seemingly not been on all night as the room was rather cold (16C). So, I cleared the binding on the T87RF, and re-bound it to the "Kitchen" zone on the evohome controller. After doing that, the UFH sprang to life and has been on ever since, trying to heat the zone; the set point is 21C and the current temp is 19C, so it has a little way to go to restore things to their former comfortable temp.

Perhaps it was the sequence in which the two were bound? Initially, I bound the T87RF first and then the BDR91, which didn't work. But then after re-binding the T87RF, that appears to have fixed things (so far, fingers crossed). I hope it works this time if anything to have my wife's confidence in me restored!

Phil