Replacing Potterton EP3002 programmer with Hive

[DaveMatt7]

Hi. I am hoping that someone can clarify a few things for me on my HW/CH system in the house I have recently moved into. I would like to fit a Hive Active Heating system – my current programmer is a Potterton EP3002 which has no independent settings for hot water and central heating.

I have a Worcester Bosch 40CDi combi boiler on the ground floor in a cloaks room, a Megaflow CL250HE hot water tank in the airing cupboard upstairs, a Potterton EP3002 programmer on the ground floor in the utility room and of course a room thermostat in the main entrance hall. The 3A fused power switch is located in the cloaks room next to the boiler.

I have what I assume is a S-Plan wiring system in a Danfoss Wiring Centre next to the boiler into which goes the connections from 2 x 2-port valves (HW & CH), cylinder stat, and pump ( ). I can also see 4 x cables coming into the wiring centre from under the floor, and am currently trying to work out what these 4 cables are connected to.
Presumably one is for mains power from switch downstairs ( ), one from downstairs room stat () and one from EP3002 programmer (). I am not sure what 4th cable is from! It isn’t from boiler as that is connected to downstairs switch (white cable in switch image).

Regardless of this I assume that the change over to the Hive is pretty straightforward but I just wanted to check first to confirm the connections.

1. Existing Programmer (EP3002; see image above) has connections to L (orange), N (blue), E, 3 (HW ON? grey), 4 (CH ON? brown) – I cannot find any instructions online for this programmer but assume from what I have found on here that 3 is for HW and 4 for CH? There is also a link from L to terminal 5 with a brown wire – which I think is not required in Hive and so can be removed. Is this correct? Otherwise connections are just a straight swap – N, L, 3 (HW ON), 4 (CH (ON)?


2. I assume that as the Hive is controlled by a wireless room stat I need to disconnect the old one, which means tracing it somehow back to the wiring centre and then disconnecting the cable and putting a wired link between where the room stats live and switched live were connected. Is that correct?

Thanks for any help in confirming this before I go ahead with it.

 

[Johnmdc]

All your comments are correct. Well worked out.
The fourth wire will be the switched live to the boiler. It looks like only the brown is used you can see it in your picture of the spur on a connector.

 

[DaveMatt7]

All your comments are correct. Well worked out.
The fourth wire will be the switched live to the boiler. It looks like only the brown is used you can see it in your picture of the spur on a connector.

Many thanks for the confirmation. Much appreciated. Once I trace back the room stat I will get on with this.

 

[DaveMatt7]

Hi guys, I would be grateful for some further help before I start disconnecting the room stat and programmer. I think I have now traced all the wires correctly, including the wires from the room stat to the wiring centre - see image below (sorry just noticed I forgot to draw in the link wire between terminals 15 and 16). So can I please clarify that when disconnecting the room stat wires in the wiring centre (black wire in terminal 4 and brown wire in terminal 9) all I then need to do to ensure current flows from programmer direct to CH valve is use a piece of wire to connect terminals 4 and 9/10. Is that correct?

Having done all of this work in identifying the wires etc I have noticed a potential problem with the boiler which is a Worcester Greenstar 40CDi Conventional boiler for use with LPG. It is for a sealed CH system and indirect HW coupled with a Megaflow. It was the single black-connector-brown wire in the switch that alerted me to this, plus now seeing that the boiler and pump wires in terminal 16 in the wiring centre are connected together when for overrun I assume that terminal 16 would be connected to boiler SL and then boiler PL would connect to the pump live. So I have opened up the boiler to check and can see firstly that ST10 which is connected to mains (L & N) via switch is directly connected with link wire to Ls and Ns, respectively.

The black wire connected to wiring centre is not switched live but actually connected to the Live Return (Lr). Is this correct, it is not how it is shown in the installation manual!

However, it is clear looking at ST2 terminals that there is nothing connected as suspected, which I assume means no pump overrun! Is this pump overrun absolutely necessary? I thought that this was a safety feature and wonder why it wasn't done. I guess it could still be added but now it is going to be a pain trying to run a cable from these connections up to the wiring centre upstairs. I am thinking that I need to get a heating engineer in to check this out. But assume in the meantime that this will not stop me going ahead and switching progarmmer and room stat as mentioned above?

Thanks in advance for any help that anyone can give on these points.

 

[stem]

I think you are over complicating it. If your system is wired up and working correctly now, changing to a Hive won't make any difference to how anything works, and there is no need to change anything at the boiler.

The EP simply contains two 'on' and 'off' switches. One for the heating and one for the hot water. The Hive Dual Channel is exactly the same. Electrically speaking you are just changing one switch for another identical switch. No difference.

The EP has the connections as below, and it actually shows the internal switches for you.

The wires from the EP move to the Hive connections that have the same function, and in your case the terminals correspond, N-N / L-L / 3-3 / 4-4. The wire link presently in the EP between terminals L and 5 is discarded as this is already made for you inside the Hive, so the Hive doesn't need or have a terminal 5.

Once the Hive is installed, because it contains both time and temperature control, the existing room thermostat should be taken out of service so the Hive can have exclusive control over both functions.

I assume this is the photo of your thermostat wiring:

This can be decommissioned by either.

1) leaving the existing room thermostat in place and moving the brown wire from terminal 3 and putting it in terminal L along with the black wire, Electrically, this is the same as the thermostat calling for heat. If you want to remove the old thermostat, then the same thing can be achieved by:

2) Tracing the cable back to its origin, which you show below. Then disconnect the cable completely, taking care not to disturb any other wires. Finally insert a wire link to join together the terminals that you have just removed the brown and black wires from. So based on your diagram:

Becomes:

 

[DaveMatt7]

I think you are over complicating it. If your system is wired up and working correctly now, changing to a Hive won't make any difference to how anything works, and there is no need to change anything at the boiler.

The EP simply contains two 'on' and 'off' switches. One for the heating and one for the hot water. The Hive Dual Channel is exactly the same. Electrically speaking you are just changing one switch for another identical switch. No difference.

The EP has the connections as below, and it actually shows the internal switches for you.

View attachment 153326

The wires from the EP move to the Hive connections that have the same function, and in your case the terminals correspond, N-N / L-L / 3-3 / 4-4. The wire link presently in the EP between terminals L and 5 is discarded as this is already made for you inside the Hive, so the Hive doesn't need or have a terminal 5.

View attachment 153327

Once the Hive is installed, because it contains both time and temperature control, the existing room thermostat should be taken out of service so the Hive can have exclusive control over both functions.

I assume this is the photo of your thermostat wiring:

View attachment 153329

This can be decommissioned by either.

1) leaving the existing room thermostat in place and moving the brown wire from terminal 3 and putting it in terminal L along with the black wire, Electrically, this is the same as the thermostat calling for heat. If you want to remove the old thermostat, then the same thing can be achieved by:

2) Tracing the cable back to its origin, which you show below. Then disconnect the cable completely, taking care not to disturb any other wires. Finally insert a wire link to join together the terminals that you have just removed the brown and black wires from. So based on your diagram:

View attachment 153330

Becomes:

View attachment 153331

Many thanks stem for your clarification and sorry if I have over complicated it. Yes that is the room stat wiring but my diagram is also representating that same room stat, so if I remove the room stat then there is nothing to bridge (ie brown to black L in your 'becomes' figure) as the stat has been removed. I guess I could connect the black and brown using a small connector and then place that into the hole in the wall where the stat had been?

Alternatively I have traced the wires back to the 16-terminal wiring centre upstairs (top part of my diagram) with the brown going into terminal 9 and the black into terminl 4. I had assumed all I needed to do was disconnect these wires and then bridge these two terminals with wire. That was what I was trying to confirm. Many thanks.

 

[stem]

Unfortunately, the room stat can't just be removed, otherwise the heating wiring will be permanently open circuit (as if the thermostat was satisfied or 'off') and the heating won't come on. So a link has to be made to complete the circuit at some point. You have two choices. Electrically they both achieve the same thing

1) At the existing room thermostat simply move the wire from 3 to L so that the brown and black wires are linked together. Leave the thermostat and the cable going to it in place.

or

2) Remove the thermostat and the cable going to it. Then make the link where the thermostat brown and black wires have been removed from. From your diagram below as this is labelled "room stat" I assumed this shows the end of the room stat cable. Unfortunately I can't see most of your diagram clearly enough to read or follow the rest of it.

If the above is not the room stat cable, ignore what I said before, and instead, if the thermostat cable goes to 9 & 4...

I have traced the wires back to the 16-terminal wiring centre upstairs (top part of my diagram) with the brown going into terminal 9 and the black into terminl 4.

...then they are the two terminals that you should bridge, once the cable is removed.

I guess I could connect the black and brown using a small connector and then place that into the hole in the wall where the stat had

You could do this, but the connector should be contained in an enclosure for electrical and mechanical protection, and it must be left visible. Wiring regulations stipulate that an 'accessory' must be present to indicate the presence of a cable above.

 

[DaveMatt7]

Unfortunately, the room stat can't just be removed, otherwise the heating wiring will be permanently open circuit (as if the thermostat was satisfied or 'off') and the heating won't come on. So a link has to be made to complete the circuit at some point. You have two choices. Electrically they both achieve the same thing

1) At the existing room thermostat simply move the wire from 3 to L so that the brown and black wires are linked together. Leave the thermostat and the cable going to it in place.

or

2) Remove the thermostat and the cable going to it. Then make the link where the thermostat brown and black wires have been removed from. From your diagram below as this is labelled "room stat" I assumed this shows the end of the room stat cable. Unfortunately I can't see most of your diagram clearly enough to read or follow the rest of it.

View attachment 153344

If the above is not the room stat cable, ignore what I said before, and instead, if the thermostat cable goes to 9 & 4...

...then they are the two terminals that you should bridge, once the cable is removed.



You could do this, but the connector should be contained in an enclosure for electrical and mechanical protection, and it must be left visible. Wiring regulations stipulate that an 'accessory' must be present to indicate the presence of a cable above.

Thanks once again and apologies if the drawing was not clear, it was supposed to represent the wires going into the room stat not the other end of the cable going into the wiring centre. It is hopefully clearer in the diagram below (sorry don't seem to be able to rotate it!) - simplified version of the complete system shown earlier. So I will just go ahead and remove the cable as indicated (disconnect from terminals 4, 6 & 9) and then use a bridge between 4 and 9 which will permanently close the circuit. Many thanks for your help confirming this.

 

[stem]

Yep that's it. Sorry for the confusion earlier

 

[DaveMatt7]

Yep that's it. Sorry for the confusion earlier

No need to apologise, you have been a great help. Many thanks.