Honeywell DT92E

[old wrinkly]

I want to replace my wired Honeywell DT90 with a Honeywell DT92E wireless.

I have looked at the installation and user guides and there is a section on low battery warning on the transmitter unit. There is a diagram of the batteries being removed but when I look at the unit the batteries seemed to be housed in molded cover and I can't see how I can lift that to gain access to the batteries when they need replacing (see image).

Second question-as I understand it the new receiver unit requires a permanent 240v feed. I haven't checked yet to see how many cores the current feed from the Honeywell junction box has, which I installed myself several years ago, but I suspect it will only be 3 core. How many cores will I need for the new cable.

Thanks

 

[Dan Robinson]

You're looking at the back.

The batteries come out of the front.

You'll need 3 cores and an earth to make it work.

 

[old wrinkly]

Wow Dan that's quick....simple when you know how!!!

I have an oil fired boiler does that affect the wiring at all (I see there are 2 diagrams for wiring the boiler]

Thanks again.

 

[Dan Robinson]

Only if you have gravity hot water does it affect the wiring.

You should also adjust the TPi settings to only cycle 3 times an hour.

 

[Hot&Cold]

I want to replace my wired Honeywell DT90 with a Honeywell DT92E wireless.

qUICK ASK
Why do you want to exchange a wired to rf. Is it a new position ?

honeywell DT series stats are very good products with adjustable parameters,very good products.

 

[old wrinkly]

Dan, disaster........thought I would see what type of cable I had from the stat and took off the Honeywell Junction Box and as I removed the cover one of the wires came free (the grey one on the bottom right). Put it back into the terminal block but boiler wouldn't run although the room stat is showing heat being called for. Looked again more closely and the grey wire doesn't have a corresponding wire going from/to it at the block. It is attached to the terminal 3 on the bottom. Completely fazzed now as don't know which wire to connect it to. Used to have a wiring diagram but not seen it for some years so I am blind. Image of junction box below.

The image is slightly distorted because the brown cable goes to the black cable tagged with yellow tape (terminal 3 on the top). This cable comes from the Horstmann Centaur Heating Control which is the other side of the cupboard.

The cable marked "Boiler" is attached to terminals 1-6 (the cable has the 3 black marks on it) on the bottom. The cable next to it with the red tag is the tank stat,

Old&Bold reason for change is I am trying to get the heating in our bungalow right. At the moment with the stat where it is in the lounge in a corner the temperature goes high (there is about a 2.5 degree difference between each end of the room) and the heating turns off and our bedroom which is the coldest room in the property gets very cold. I am going to put the wireless transmitter in the bedroom initially and see if I can get a better balance. if that doesn't work I will move it about until I get the best position. Spoke to our boiler maintenance man and he thought that was a good idea and said a lot of people with log burners have to do this because the log burner makes the room temperature rise sharply making the stat ineffective.

 

[old wrinkly]

Just a thought but as I want to install the wireless thermostat would it be better to ask if someone could give me an idots guide as to what wires to connect to what to get the new one working. I've done wiring in the past but as I get older I am less confident in my abilities.

Something like terminal 1 from thermostat to terminal 3 on the junction box would be great as I'm sure I can follow clear instructions and I can get my heating sorted in one step.

Fingers crossed??

 

[HERTS P&D]

Where's Stem when you need him.

Andy

 

[stem]

Where's Stem when you need him.

Andy

I'm working on site today at a Waste to Energy plant. Won't be home until late but will try to take a look when I get in, or in the morning.

Unfortunately these systems are wired up using cable colours and terminals selected according to the personal preferences of the original installer. To fault find, it's necessary to know where the wires are connected to at the other end.

Old wrinkly, if you could post details of what is connected to the other end of the wires in the grey cable, that would be helpful. Also what is connected to the white wire going to the motorised valve (black cable)?

Word of caution though, if you keep trying to guess where they wires go and get it wrong, you could do some serious (expensive) damage.

 

[Echo the husky]

I assume this is Y plan with a 3 port valve? If it is and the grey wire that came out is part of the room thermostat, then it will connect with the white wire on the 3 port valve (which is heating on).

 

[old wrinkly]

Hi guys, just got in from evening out. Echo the husky yes this is a Y Plan and the black cable goes to that so can I confirm that you saying the grey wire that was loose connects to the white wire in the black cable?

Stem the white wire in the black cable has nothing connected to it, the image is a bit distorted because of the way the camera is held. The white wire is on terminal 4 and the two black wires above are terminals 3 and 5.

There isn't any grey cable. If you are referring to the grey and brown wires on terminals 2 and 3 respectively these are in a white cable (flash distorting colour) and go to the current DT90 room stat.

Take you point at not just poking about blind, don't want to screw everything up.

Hope this is clear enough.

 

[Echo the husky]

Yes it goes in with the white wire then.

 

[old wrinkly]

Echo the husky I have heat so that seems to have worked and at the moment nothing has gone bang! Will take a photo in the morning to keep as a record of the wiring or even make a diagram (won't get caught out again).

Next step is to connect the new DT92E into the system. I have sufficient cores in the white cable from the current DT90 so an idiots step by step guide for where everything goes would be really helpful.

Thanks to everyone for their help so far.

 

[stem]

Glad to hear you got it working again.

The DT90E thermostat will have come with a receiver. You don't give details of this but it is usually a BDR91, so the details below are based on this. If yours has a different receiver don't proceed and paste back details of what you have.

The DT90 is wired as below. From your previous posts, terminals A and B will be connected to the Grey and Brown wires from the cable mentioned earlier.



The BDR91 is wired as below. So the Grey and Brown wires would go back in A & B exactly as they are now.

The BDR91 also needs a permanent live and neutral for the 230V to operate the receiver. This should come via the same fused spur as the rest of the heating system.

EDIT
The Y Plan system doesn't always require a permanent live supply to the wiring centre, so there isn't always one present. However, I have worked through the wires in the photo of your wiring centre and eliminated the others, just leaving terminal 9 without a function. It appears to have a single brown wire in it with nothing else connected to it. This could be from the fused spur, possibly via the programmer L terminal. But check first before using it as the live supply to the BDR91. The neutral is terminal 8. and earth 10.

 

[old wrinkly]

stem thanks for the very clear explanation. Before I start I am going to make up a full diagram of the Honeywell Junction Box so I can keep it with the other instructions etc. for the property.

Can I get a wiring diagram for the Honeywell Y Valve v4073a1039 so I can make a note of the connections on the Honeywell Junction Box diagram.

I will post back when the job is completed but this may not be for a few days as waiting to see if my grandson who is a fully qualified electrician is going to come over and help his grandad out!!!