Valiant 831 Boiler - Wiring of thermostats and motorised valves?!

chriswrench1989 · Mar 10, 2015

Sorry in advance for the long thread! Just want to make sure i provided as much detail as possible.

We are currently building an extension and whilst devastating the house have decided to install a new boiler, we have also opted for a John Guest UFH system to be installed in the new extension.

I installed the boiler and rerouted the pipe work (we previously had a boiler and tank upstairs) over the weekend and then had a qualified plumber connect the gas and commission the boiler yesterday.

I was also expecting him to complete the wiring of the motorised valves and stats however he seemed to lack knowledge on how these should be connected and just wired so that the boiler worked until an electrician had a look. Im not convinced its right!

At the moment we have no control over the heating and I would like some advice on how to connect up the devices.

Overview of system
Boiler - Valiant Ecotec Plus 831 combi

Heating zones -
1 zone for radiators
1 zone for UFH system

The Heating flow from boiler is connected to 2, two way motorised Honeywell valves. 1 valve serves the radiator heating zone, and the other valve serves the UFH manifold.

I have been advised that we require 2 independent programmers/thermostats for each zone.

For Zone 1 (Radiators) I have currently used the stat from the previous boiler as it was only few months old. This is a Horstmann Centaurstat 7 which is a 7day, single zone programmer allowing 3 programmes per day.

For zone 2 I have purchased a new JG 12v Programmable 7day thermostat.

I therefore have 2 programmers/stats and 2 motorised valves. One for each heating zone.

The UFH manifold pump has an automatic temperature sensor to shut off its pump when the motorised valve is closed.

The plumber has currently wired all 4 devices into a central wiring box including a feed to the boiler.

I would be extremely grateful if someone could help me on how the various devices should be wired into the connector block/ boiler.

The only control we currently have is to physically turn the boiler on and off if we want the heating, neither thermostat or programme seem to control the boiler!

Not ideal waking up in the morning to a cold house and having to manually turn the boiler on!!

Thanks for your help in advance, please let me know if I need to provide any extra details!

I have some pictures of the installation that i would like to upload, but my permissions don't seem to allow it currently??

Chris

Leesparkykent · Mar 10, 2015

http://heating.danfoss.co.uk/PCMPDF/021v01.pdf page 18 and 19

or alternatively you could fit a kit like this

http://www.honeywelluk.com/Documents/Installation-Guide/pdf/Sundial RF² Pack 5 - Installer Guide.pdf

these Honeywell kits are the mutts nuts IMO.

davesparks · Mar 10, 2015

Wiring diagrams for a 2 zone system (S plan) are included in the sticky thread at the top of this section of the forum.
You will of course have to make the appropriate adjustments for the combined stat/programmer and the 12V unit you have (why did you go for 12V?)
Other than that the only advice we can really give is to employ an electrician with a good working knowledge of domestic heating controls.

davesparks · Mar 10, 2015

Leesparkykent said:
http://heating.danfoss.co.uk/PCMPDF/021v01.pdf page 18 and 19

or alternatively you could fit a kit like this

http://www.honeywelluk.com/Documents/Installation-Guide/pdf/Sundial RF² Pack 5 - Installer Guide.pdf

these Honeywell kits are the mutts nuts IMO.

If that Honeywell kit is the one with the pcb in the joint box they are far from being the mutts nuts, damned things are plagued by dry joints on the pcb's.

Leesparkykent · Mar 10, 2015

davesparks said:
If that Honeywell kit is the one with the pcb in the joint box they are far from being the mutts nuts, damned things are plagued by dry joints on the pcb's.

No it's a twin channel programmer that is also the receiver for the two wireless room thermostats that come as part of the same kit for each zone and also has a connection for volt free connections etc 2 the boiler if required

I agree about the Honeywell sundial idiot proof wiring centre the PCB's are sh!t. If I get supplied one on a job I rip the pcb out and use connector block or wago's.

Geordie Spark · Mar 10, 2015

chriswrench1989 said:
Sorry in advance for the long thread! Just want to make sure i provided as much detail as possible.

We are currently building an extension and whilst devastating the house have decided to install a new boiler, we have also opted for a John Guest UFH system to be installed in the new extension.

I installed the boiler and rerouted the pipe work (we previously had a boiler and tank upstairs) over the weekend and then had a qualified plumber connect the gas and commission the boiler yesterday.

I was also expecting him to complete the wiring of the motorised valves and stats however he seemed to lack knowledge on how these should be connected and just wired so that the boiler worked until an electrician had a look. Im not convinced its right!

At the moment we have no control over the heating and I would like some advice on how to connect up the devices.

Overview of system
Boiler - Valiant Ecotec Plus 831 combi

Heating zones -
1 zone for radiators
1 zone for UFH system

The Heating flow from boiler is connected to 2, two way motorised Honeywell valves. 1 valve serves the radiator heating zone, and the other valve serves the UFH manifold.

I have been advised that we require 2 independent programmers/thermostats for each zone.

For Zone 1 (Radiators) I have currently used the stat from the previous boiler as it was only few months old. This is a Horstmann Centaurstat 7 which is a 7day, single zone programmer allowing 3 programmes per day.

For zone 2 I have purchased a new JG 12v Programmable 7day thermostat.

I therefore have 2 programmers/stats and 2 motorised valves. One for each heating zone.

The UFH manifold pump has an automatic temperature sensor to shut off its pump when the motorised valve is closed.

The plumber has currently wired all 4 devices into a central wiring box including a feed to the boiler.

I would be extremely grateful if someone could help me on how the various devices should be wired into the connector block/ boiler.

The only control we currently have is to physically turn the boiler on and off if we want the heating, neither thermostat or programme seem to control the boiler!

Not ideal waking up in the morning to a cold house and having to manually turn the boiler on!!

Thanks for your help in advance, please let me know if I need to provide any extra details!

I have some pictures of the installation that i would like to upload, but my permissions don't seem to allow it currently??

Chris