Thermostat Problem

[Chewy56]

Is this as far as I can take this post Thermostat Problem | on ElectriciansForums - https://www.electriciansforums.net/threads/thermostat-problem.215331/

I have no intention of doing any electrical work myself.

 

[Alk]

Hi @Chewy56
I cannot reply to your original thread - it says that I have insufficient privileges to do so - I cannot post anywhere in that forum/start a new thread (what's up with that? - have you got the same problem, hence why you started this new thread?).

I just wanted to say that if there is a green light on your BDR91 receiving box (which is next to the boiler) then it means that either: 1. you have pressed the little grey button on the receiving box manually yourself (you only ever do this in a situation when there is a lack of communication) or 2. The receiver is communicating with the DT92E Thermostat correctly.
The green light indicates that the receiving box has switched the boiler on to operate, so if the light is on, then it is communicating with the thermostat if you otherwise haven't touched it.

If the thermostat is in the room directly below the BDR91 receiving box then there should be no issues with wireless communication.
When you change the batteries, there is no need to re-link the devices.

In summary, you changed the batteries (it sounds like it needed new ones) and it is working again.
To confirm that everything is working correctly:
First make sure that the green light on your BDR91 is off.
Then on the DT92E thermostat, increase the temperature to 30 degrees Celsius (for testing, it must be way way above your normal set room temperature).
At this point you should see that the thermostat display pops up with a "radio" signal of dashes, along the bottom. This means that the thermostat is transmitting a signal to the BDR91 box.
At this point, your BDR91 receiving box light will go green and the boiler will switch on and your radiators will heat up.
Be aware that sometimes there is a slight delay between the BDR91 light going green and the boiler switching on, even though there is a radio signal on the thermostat display. This is due to the way that the Honeywell thermostats work to achieve energy efficiency - it is not a fault.
If all is in order, on the DT92E thermostat, decrease the set temperature back to your normal room temperature that you are comfortable with.
The green light on the BDR91 box should now go off.

 

[Chewy56]

Hi @Chewy56
I cannot reply to your original thread - it says that I have insufficient privileges to do so - I cannot post anywhere in that forum/start a new thread (what's up with that? - have you got the same problem, hence why you started this new thread?).

I just wanted to say that if there is a green light on your BDR91 receiving box (which is next to the boiler) then it means that either: 1. you have pressed the little grey button on the receiving box manually yourself (you only ever do this in a situation when there is a lack of communication) or 2. The receiver is communicating with the DT92E Thermostat correctly.
The green light indicates that the receiving box has switched the boiler on to operate, so if the light is on, then it is communicating with the thermostat if you otherwise haven't touched it.

If the thermostat is in the room directly below the BDR91 receiving box then there should be no issues with wireless communication.
When you change the batteries, there is no need to re-link the devices.

In summary, you changed the batteries (it sounds like it needed new ones) and it is working again.
To confirm that everything is working correctly:
First make sure that the green light on your BDR91 is off.
Then on the DT92E thermostat, increase the temperature to 30 degrees Celsius (for testing, it must be way way above your normal set room temperature).
At this point you should see that the thermostat display pops up with a "radio" signal of dashes, along the bottom. This means that the thermostat is transmitting a signal to the BDR91 box.
At this point, your BDR91 receiving box light will go green and the boiler will switch on and your radiators will heat up.
Be aware that sometimes there is a slight delay between the BDR91 light going green and the boiler switching on, even though there is a radio signal on the thermostat display. This is due to the way that the Honeywell thermostats work to achieve energy efficiency - it is not a fault.
If all is in order, on the DT92E thermostat, decrease the set temperature back to your normal room temperature that you are comfortable with.
The green light on the BDR91 box should now go off.

Many thanks for your reply. My original question on the other board was:
Hi, First post and would be very grateful for any help.

I have a Honeywell DT92E Thermostat that is only intermittently communicating with the wireless relay box BDR91.

There is a full green light on the BDR91 and if I switch the Potterton programmer on HW and CH the radiators come on and switch off when it it reaches the temperature on the DT92E after that any communication stops. The BDR91 is in a very inaccessible place. Is there any way I can sort the problem out on the DT92?. I have seen a video showing how to rebind the two but I don't think I will be able to get to it!'

I will go through your reply today and let you know how I can on.

 

[Chewy56]

Many thanks for your reply. My original question on the other board was:
Hi, First post and would be very grateful for any help.

I have a Honeywell DT92E Thermostat that is only intermittently communicating with the wireless relay box BDR91.

There is a full green light on the BDR91 and if I switch the Potterton programmer on HW and CH the radiators come on and switch off when it it reaches the temperature on the DT92E after that any communication stops. The BDR91 is in a very inaccessible place. Is there any way I can sort the problem out on the DT92?. I have seen a video showing how to rebind the two but I don't think I will be able to get to it!'

I will go through your reply today and let you know how I can on.

I have been through your post and the green light is showing on the BDR91 all the time. I looked at it before I put the heating on this morning and it was green. When I put the heating on it was still green and when I switched it off it was still green (as photo 1 attached). Photo 2 shows the DT92 when the heating was first switched on this morning. I had already set the temp to 30% but I knew from the intermittent problem from the past two days that although no wireless signal was showing that the radiators would heat up so I did not leave the heating on! Photo 3 shows the programmer when the heating was switched on this morning (need to reset the clock to winter time).

 

[Alk]

From everything that you have explained, I believe that the problem is with the CH scheduling on your Potterton programmer.
Here is my logic:
You have explained that when you manually switch the Potterton programmer to ON, that the room then heats up to the temperature set on the thermostat and then it switches off. If the thermostat were not communicating with the BDR91 relay box correctly, then that would not happen and you would not be able to get the heating to come on in this way.

As you no doubt know, the Potterton programmer will get in the way of the thermostat working.
So let's take an example where you have the CH set to OFF on the programmer; then it doesn't matter what is set on the thermostat, the heating just won't work. The thermostat will continue to try and reach the say 25 degrees C that you have set to be the target room temperature, but it just can't do so, because it has been overridden by the Potterton programmer and the boiler is actually off. Likewise, I think I'm right in saying that in this situation that the green light will still be on, showing that it has received the signal from the thermostat and is "calling for heat" from the boiler (attempting to reach the 25 degrees), but because it has been overridden by the OFF on the programmer, the boiler is actually off and nothing happens at your radiators - so the light continues to remains on, attempting in vain to get to 25 degrees.

So this is just the same as when you have a schedule setup on the Potterton programmer. When the programmer schedule is set for the CH to be off, the thermostat cannot work. The thermostat can only reach the target temperature when the programmer schedule is set to be ON (just the same as when you manually switch it to ON) and with sufficient time allocated on the schedule for it to reach that temperature (say you need a minimum of 2 hours to heat the house to the target temperature of X degrees? - you won't be wasting energy once it has reached the target temperature, it will just maintain the set temperature).

So in summary, please check the Potterton programmer's Central heating schedule and check it is set correctly. It would be best to have a pen and paper handy as you will have to go through and check each day.