Wiring - Swap Nest-E for Worcester Easy Control on EMS

[Ccw71]

Life 8000 heat only boiler, currently controlled by Nest-E.

Hi all, I just bought a Worcester Bosch Easy Control thermostat to replace my Nest-E which is only operating as an on/off stat due to not being compatible with Worcester Bosch EMS on my Life 8000 heat only boiler. I want to take advantage of Load and Weather compensation, which the Easy Control can do on the EMS bus. Both stats require only 2 wires, so I can repurposed the existing cable.

When the Nest was installed, the boilers jumper "Link" wire(s) were removed by my installer as required for 3rd party controllers, and it's not so clear where I should put them back? I'm thinking it's 230v out to LR? If so do I need to a 230V link to both CH and HW as this is a heat only boiler?

I'm assuming I will be removing the LR Heating at the boiler (from NO at Nest), to then be re-purposed as 1 wire from the new stat to the boilers EMS connection and the 230v connection currently running from the (external to so not seen in the picture) boiler to the Nest (C) as the other EMS connection?

Many thanks for any input.

 

[awhite243]

The EMS connection is a bus style connection and therefore requires a loop. It also will only low voltage, therefore if you connect anything like 230v to the EMS terminals. The result would be pretty terminal.

Unfortunately I have the same boiler but a different controller (Tado- which is in the same boat as the Nest E). However when my boiler was installed, the installers just put the two EMS from the Tado into the EMS ports on the boiler. They didn't remove the jumper cables.

Therefore I'd say that you'd re attach the two jumpers to put it back to "factory". And then wire the two wires into the EMS ports (being a bus there is no polarity)

 

[Ccw71]

If your boiler is heat only, ie not a system boiler, do you know which connections the jumpers attatch to?

 

[awhite243]

Please see below, both CH and DHW want to be connected to the live terminal of the 230v out.

You can also see it in this video:

https://www.facebook.com/video.php?v=1411599455852038

Where the guy is starting afresh with a WB8000 and installing Hive.

Hope this helps

 

[Ccw71]

Thanks. This boiler is a system boiler as I cought a glimpse of an expansion vessel in it. But I guess connecting up both Ch and HW to the 230v wont do any harm. I noticed he also did not remove the white "on/off" jumper wire. Again I can't see how if I put it back it will do any harm, just maybe affect the functioning of the controller? Thanks again for that.

 

[awhite243]

Just because it has an expansion vessel doesn't make it a system boiler. A combi has one too.

The attached photo shows the expansion vessel of a WB 8000 combi.

 

[RandomGrinch]

But I guess connecting up both Ch and HW to the 230v wont do any harm.

If in doubt RTM!

Yes, the links join from L (supply), to the LR (Live Return) of CH and HW.

 

[Ccw71]

Thanks RandomGrinch.

Any idea about the "on/off thermostat input" link? This is fitted by default (perhaps to allow the intaller to fire up the boiler without any external controls). It was removed by my installer when the Nest was fitted, but I see it is still present in the video above after installing the Hive. With an EMS thermostat, should it be fitted or not?

I'm surprised there appears to be no instructions from WB on how to install these Easy Control thermostats.

 

[awhite243]

I happened to speak to my boiler guy yesterday. As I am in the middle of deciding if easy control is what I want.

He said the links stay in, so the boiler is powered 100% of the time. The EMS controller then has utilmate control.

In other words, if the link isn't in, and the EMS bus is wired correctly, you'll have no control of the boiler.

I was lead to believe the Easy Control could be used wirelessly and if so, it's just a plug and play. But I am assuming you are hardwiring it? I agreed, nothing seems are simple as it should be. But then again, Bosch doesn't want Joe Bloggs fiddling with the inside of the boiler.

 

[Ccw71]

Thanks awhite243.

Wireless would be simple, unfortunately I don't think the signal would reach as the boiler is quite a distance from the stat. I've heard quite a few complaints about signal drop outs. Not sure if people are refering to the WiFi or the wireless link, but at least I can eliminate one possibility by hard wiring as the cable's already there.

 

[awhite243]

That is also something the boiler guy said. He had the Easy Control wireless and it was very temperamental.

Cut a long story short, he went with Hive, which is what I am going to do. Easy control makes sense to me in a well plumbed house, unfortunately mine is very convoluted. So back to bog standard on/off

 

[Ccw71]

I don't have any fancy zones or smart trv's either, but I picked up the Easy Control for a good price, so thought I'd give it a go. I'll be hanging on to the Nest E just in case.

 

[Ccw71]

I'm nearly there (I think) but I've started a new thread titled "2 port valve wiring Easy Control CT200 EMS S Plan" Please help if you can.