Heating Programmer Wiring

[starocean]

Hi,

My parents EPH T27-HW programmer has kicked the bucket. Display completely dead, even after replacing CR2032 battery.
It seems this particular model is as old as the hills and we pretty much can't buy it new anymore.
Instead an EPH R27-V2 was purchased. However i'm finding it very hard to get my head around the differences with the wiring between the two units.
The older model is an 8-pin backplate and the newer one is a 6 pin backplate.
It's worth noting that i think the exisitng programmer is a 2 zone one however my parents only have 1 thermostat downstairs, and nothing upstairs.

Wiring for T27-HW as below:

And i can see on the wall that 5 and 8 have nothing connected to them and 4 and 7 are daisy chained to 1.

On the new R27-V2 the naming doesn't seem to correlate:

Anyone here that could please make sense of the differences between the diagrams?

Thanks

 

[Taylortwocities]

I have a feeling that you should have bought a programmer that has separate controls for hot water and heating.
If you really want EPH then the A27-HW is the one you want. It has separate buttons for heating and hot water, like the old one has.
The EPH R27-V2 would appear to be designed to control two heating zones, which is not the situation.

You may be able to cobble the EPH R27-V2 in to the existing wiring. The reason that it is only 6 pin is because the live loop in the old one (L>4>7) is provided internally in the EPH R27-V2, as shown in the product diagram.

 

[flameport]

L brown N blue to the supply terminals, E to the separate E terminal.
Black wire to HW On #3
Grey wire to CH On #4

The brown links are internal on the new one so not required, the other 'off' terminals #1 and #2 are not used.

 

[starocean]

I have a feeling that you should have bought a programmer that has separate controls for hot water and heating.
If you really want EPH then the A27-HW is the one you want. It has separate buttons for heating and hot water, like the old one has.
The EPH R27-V2 would appear to be designed to control two heating zones, which is not the situation.

You may be able to cobble the EPH R27-V2 in to the existing wiring. The reason that it is only 6 pin is because the live loop in the old one (L>4>7) is provided internally in the EPH R27-V2, as shown in the product diagram.

We had actually ordered a different unit but this is what was sent to us Was hoping i could just make it work with what was already there. Thanks for the input.

 

[Taylortwocities]

We had actually ordered a different unit but this is what was sent to us Was hoping i could just make it work with what was already there. Thanks for the input.

You probably can 'make it work' - follow Flameport's instructions.
If i had elderly parents they might want easy to understand buttons that say "heating" and "hot water".

If its the wrong one, send it back.

 

[starocean]

You probably can 'make it work' - follow Flameport's instructions.
If i had elderly parents they might want easy to understand buttons that say "heating" and "hot water".

If its the wrong one, send it back.

Funnily enough, the R27-V2 is quite basic in terms of the buttons that are on display. "Boost HW" and "Boost Heating". That's pretty much all my parents do. They don't have timers set etc.

 

[Taylortwocities]

Funnily enough, the R27-V2 is quite basic in terms of the buttons that are on display. "Boost HW" and "Boost Heating". That's pretty much all my parents do. They don't have timers set etc.

ah. Fair enough.

So, L & N as they are on the old one.
No links needed.
the black (hot water) that is on 3 on old goes to 3 on the new. = zone 1*
The grey (heating) that is on 6 on old goes to 4 on the new. = zone 2*

The titles on the buttons can be zone or heating/hot water.
see P04 zone title in the instructions if you need to change the display title.

 

[ericmark]

If i had elderly parents they might want easy to understand buttons that say "heating" and "hot water".

Yes, easy to understand is important, I found the Nest Gen 3 was good for that, and near enough same wiring diagram. I don't like the Nest, but have to admit, it is easy to use. And is also having a thermostat.

 

[starocean]

ah. Fair enough.

So, L & N as they are on the old one.
No links needed.
the black (hot water) that is on 3 on old goes to 3 on the new. = zone 1
The grey (heating) that is on 6 on old goes to 4 on the new. = zone 2

Am i correct in thinking that given my parents have only the one thermostat that basically controls both upstairs and downstairs that i should really look at installing a 1 zone programmer instead? They have no intention of having a second thermostat installed. Puzzled as to why the person who installed this put a 2 zone one there in the first place...

The issue with these newer units seems to be that the HW and Heating is no longer split out to separate buttons. On the original unit both HW and Heating had thir own "boost" buttons which made things very simple.

Thanks for the replies to date.

 

[starocean]

Yes, easy to understand is important, I found the Nest Gen 3 View attachment 393166was good for that, and near enough same wiring diagram. View attachment 393167 I don't like the Nest, but have to admit, it is easy to use. And is also having a thermostat.

The old unit did just that

Boost heating on one button, boost hot water on another.

 

[ericmark]

I could not believe it with my own parents, new gas boiler fitted, with a programmer and wall thermostat. It turned completely off overnight, what a daft idea. The programmable thermostat has been out for years, so easy to turn up or turn down, by actually turning the outer of the thermostat. This one however I had to keep instructions tucked behind it, not intuitive at all. Never had a problem with these or even these, ⁣but what *123456 means I have never worked out, what is wrong with centigrade? Why make it so you need a conversion chart?

 

[Taylortwocities]

Am i correct in thinking that given my parents have only the one thermostat that basically controls both upstairs and downstairs that i should really look at installing a 1 zone programmer instead? They have no intention of having a second thermostat installed. Puzzled as to why the person who installed this put a 2 zone one there in the first place...

The issue with these newer units seems to be that the HW and Heating is no longer split out to separate buttons. On the original unit both HW and Heating had thir own "boost" buttons which made things very simple.

Thanks for the replies to date.

Basically the programmer is two simple switches. In a situation where it is controlling heating in a house which has separate thermostats, upstairs and downstairs, perhaps, you can use this programmer the set different times etc for up and down. In that situation up and down are considered as "zones".
In your situation you have two zones, one is heating, with its own thermostat. The other zone is hot water, this too has its own thermostat, probably in the hot water tank. So its two switches.
So you can use the EPH R27-V2 in your parents house, no additional thermostats needed.
In the settings for the EPH R27-V2 you can label the two channels Zone 1 and Zone 2, or Heating and Hot Water.
Each has a separate boost button to boost by 1,2 or 3 hours.

All of this is in the instruction manual. I'm hoping you've read that???
I have had to do that to help you out.

If you think this is all too much for your parents, buy one of these

https://www.draytoncontrols.co.uk/product/lp522

you can buy them at screwfix and many other places. Simple to operate.
The boost function will simply turn on the water or heating to the next programmed on period.

 

[starocean]

Basically the programmer is two simple switches. In a situation where it is controlling heating in a house which has separate thermostats, upstairs and downstairs, perhaps, you can use this programmer the set different times etc for up and down. In that situation up and down are considered as "zones".
In your situation you have two zones, one is heating, with its own thermostat. The other zone is hot water, this too has its own thermostat, probably in the hot water tank. So its two switches.
So you can use the EPH R27-V2 in your parents house, no additional thermostats needed.
In the settings for the EPH R27-V2 you can label the two channels Zone 1 and Zone 2, or Heating and Hot Water.
Each has a separate boost button to boost by 1,2 or 3 hours.

All of this is in the instruction manual. I'm hoping you've read that???
I have had to do that to help you out.

If you think this is all too much for your parents, buy one of these

https://www.draytoncontrols.co.uk/product/lp522

you can buy them at screwfix and many other places. Simple to operate.
The boost function will simply turn on the water or heating to the next programmed on period.

I think the confusion here was born from the fact that old one is literally labelled "Boost HW/Heating" but the new one is "Boost Zone 1/2". Completely get what you're saying now about "Zone buttons" effectively doing the same job as the old units buttons.

Thanks for your help on this. Will give it a go over the weekend.

 

[ericmark]

Today, we don't need a wall thermostat, the thermostatic radiator valve (TRV) can be directly linked to a hub, and each room is its own zone. But in the past, we tended to use a wall thermostat in the coldest room. But there is nothing wrong with manual control, when I was a lad, we controlled the heating by the amount of coal on the fire.

So my parent's first central heating got the house warm while the lit the fire, it was never intended that it should run all day. I fitted a wall thermostat so they could run it all day without getting too hot.

But in my own house, the programmer and thermostat went in the 90s, and we went to the combined programmable thermostat at the same time as removing the tungsten bulbs. As we lost the heat boost as the lights were switched on.

It is easy to forget what the old central heating was like.

 

[Taylortwocities]

the new one is "Boost Zone 1/2".

I have already told you -- You can change the labels to call them water and heating instead!. RTFM

https://www.ephcontrols.com/wp-content/uploads/2023/02/2023-01-20_R27-V2_DS_135x100_JWEmail.pdf