New Programmer for Vaillant Ecofit Pure 835

[jwadley]

Hopefully someone can make light of a simple question.

My parents boiler has been replaced and checked out by a Gas Safe Engineer, but he was called away before installing the programmer/thermostat. He said we could fit this if we knew what we are doing (father former electrician).

We were sold an ESI ESRTP4RF+. Looking at the wiring though my father and I are confused. Vaillant instructions state must not use 240v... but 24v it seems.

On the mains connection block there is an RT connection, and separate X103 block with 'burner off (hard wire link), RT24= (hard wire linked) and =/- bus.

Thing is, the programmer does not mention 24v anywhere. Is this the right programmer? How should we wire it?

Many thanks for your guidance and hopefully a prompt response... parents are having to leave CH on constantly so that they have hot water (too difficult to explain how to turn the CH temperature down to turn it off, and it's sited in an outhouse!)

 

[rbranco]

24v is for using a specific Vaillant thermostat or via relay, eBUS is a specific protocol to use the vaillant controls which are the best idea to get full efficiency of those boilers by adding Weather Compensation controls such as VRC720f, its just a two wire connection if using these controls. Installers should really advise boiler specific controls IMO for Vaillant.


835 is a combi boiler so no need to have CH on all the time for HW, it will fire up as needed for HW unless there is a config option to disable that.

 

[rbranco]

Just checked install for that boiler, there should be a pin called RT, this is for 240v programmers, then remove the 24v jumper link.

Page 22

https://www.vaillant.co.uk/download...tion-and-maintenance-instructions-1943272.pdf


ps. Or get IMO get a proper VRC720f controller, its far better and efficient having WC

 

[jwadley]

Thank you.... I'll check out the vaillant controller, though my parents will probably use it in their usual on / off mode only !!
It was hard enough to get them to have thermostatic valves and explain how to use them!!

 

[jwadley]

Actually, I just had a quick look and can't see my parents going for that... multizone that they wouldn't use, the weather sensing etc is unlikely to be really used due to parents 'switch it on when it's needed' approach.
You mentioned 2 wire, which I see mains Live and RT... on the programmer, I assume this goes to COM and N/O - can we use the live, neutral from the boiler also for the supply to the programmer?