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.

 

[Avo Mk8]

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.

Your BDR91 doesn't seem to be behaving in the way I would expect, or I may have misunderstood your post.
The green light should not be on all the time, it should only come on when the DT92 calls for CH.
Secondly, if communication was lost the lower red light would be on/flashing.
The pen marks on the front suggest there has been some confusion in how it should be connected.

From what you say and the photos, the boiler controls seem to be solely responsible for controlling heating at the moment rather than the thermostat/BDR91. Has it ever worked properly?

I suggest it needs someone with a test instrument to check the wiring, maybe disconnect the BDR91 from the boiler and see if it will perform correctly with the DT92, ie both lights off, turn up the thermostat and the green light should come on, turn down the thermostat and the green light goes off.

 

[Chewy56]

Thank you very much for the replies.

Could someone advise the cheapest way out of this problem. We only use the Potterton Programmer to switch the water and central heating on and off. I realise the temperature is controlled by the DT92 and therefore the BDR91 is needed. I do not intend to do any electrical work myself but this problem could be in any one of three places and cost a lot of money to sort out.

 

[Avo Mk8]

Thank you very much for the replies.

Could someone advise the cheapest way out of this problem. We only use the Potterton Programmer to switch the water and central heating on and off. I realise the temperature is controlled by the DT92 and therefore the BDR91 is needed. I do not intend to do any electrical work myself but this problem could be in any one of three places and cost a lot of money to sort out.

The only way I can see to sort this out is for someone to check out the wiring and find what `i believe to be a fault somewhere. Ie 'Electrical work'.

If you understand electrics, you might turn the whole system off at the mains, and investigate what wire goes where. You could then draw out the circuit diagram of what you have, and compare that with example circuits on the web. That would at least establish if it's wired correctly.
Failing that you need an electrician familiar with central heating controls to do the investigation.

The BDR91 box is about £60 to purchase, but we don't have enough evidence to say that is what's wrong at the moment.

In the meantime if you set the programmer to switch on the CH for a period to provide the heat you need, and then switch off after say an hour or two, you might be able to arrive at an 'on' period that gets the house to the right temperature without using the thermostat

 

[Chewy56]

The only way I can see to sort this out is for someone to check out the wiring and find what `i believe to be a fault somewhere. Ie 'Electrical work'.

If you understand electrics, you might turn the whole system off at the mains, and investigate what wire goes where. You could then draw out the circuit diagram of what you have, and compare that with example circuits on the web. That would at least establish if it's wired correctly.
Failing that you need an electrician familiar with central heating controls to do the investigation.

The BDR91 box is about £60 to purchase, but we don't have enough evidence to say that is what's wrong at the moment.

In the meantime if you set the programmer to switch on the CH for a period to provide the heat you need, and then switch off after say an hour or two, you might be able to arrive at an 'on' period that gets the house to the right temperature without using the thermostat

Thank you for your reply.

I thought the problem that I have would be an easy fix. The set up with the thermostat, relay box and programmer has worked faultlessly for over 1 year. Just for the last couple of days, the connection symbol on the thermostat has not shown which has resulted in an intermittent problem when switching on the heating at the programmer, as described in my original post. Once the temperature reaches the ceiling figure input on the screen of the thermostat, the boiler switches off and will not fire up again until the system has completely cooled down. Ideally, once the temperature had dropped by a few degrees, it would switch on again, but this is not the case.

I still don't quite understand how the thermostat communicates with the relay box, as I have been told that it is not by WiFi.

From the comments I have received, it now seems that the problem could be with the relay box and /or a problem with the programmer, though the programmer was new about 18 months ago. If I get an electrician in, to have a look, it could end up a very expensive business, in which case I would rather put up with the fault. I would have no problem getting an electrician if it was a small job but this could turn out to be hundreds of pounds which I could not afford.

 

[Chewy56]

A friend has just recommended a Hive or Tado system which would cost around £100 to buy and an Electricians time to install.

If this was a solution to my problem I would certainly consider it. I would be very grateful for any comments.