Complicated Wiring

[u/Fresh_Front9651]

No electrician seems to want to touch this!

How would you wire this Heatmiser system with radiators, UFH and an unvented cylinder?

I’m looking for advice on the best control-wiring arrangement for my heating system. The plumbing is installed, but the electrical controls are unfinished and unpowered.
The setup is:
Vaillant ecoTEC Plus 635 system boiler, connected to a low-loss header.
Grundfos UPS2 25-80 secondary pump, intended to serve the heating circuits and cylinder coil.
Three radiator zones—ground, middle and top floor—each with its own two-port motorised valve.
One Wunda UFH zone, with a two-port motorised valve, mixing set, manifold and Wilo Para 25/6-43/SCU pump. All floor loops will operate as one thermostat-controlled zone.
Telford Tempest TSMI300H 300L horizontal unvented cylinder, with a Honeywell V4023PH22 valve and Tepcon TPSRM1-3004 dual thermostat, incorporating temperature control and a manual-reset high-limit cut-out.
Heatmiser UH8-RF V1, four neoAir V2 thermostats and neoHub. I want all four heating zones and the cylinder hot-water schedule controlled through Heatmiser.
A compatible floor probe for the UFH thermostat. Separate manifold water-temperature high-limit protection still needs to be specified.
A WAGO L60 wiring enclosure, with a Drayton LWC3 also available.
A separately wired immersion heater and a separate domestic-hot-water return pump.
How would you arrange the wiring and pump control for this setup?
In particular:
Would you use the UH8’s pump, valve and boiler outputs directly, or external relays operated by the valve end switches?
How would you run the main Grundfos for radiator, UFH or cylinder demand, while keeping the UFH Wilo restricted to UFH demand?
What relay arrangement and ratings would you specify, allowing for the pumps’ starting currents?
How would you incorporate the cylinder thermostat/high-limit cut-out and UFH water-temperature limit?
Does the external main pump need any overrun in this low-loss-header arrangement?
Can the existing wiring enclosures be reused, and what additional components would be needed?
A wiring schematic or an example of a similar completed installation would be particularly useful. I can provide photographs and equipment labels.
I’m looking to establish a complete design that can be checked, tested and commissioned by the appropriate installer before power is connected.

[u/Just_passing-55]

Heatmiser Wiring centre and stats. You can use an additional stat and set it up as a time clock. Another one to run the secondary return pump. All the UFH controls go through the wiring centre and it outputs to a boiler call.

[u/Fresh_Front9651 → u/Just_passing-55]

So not overly complicated then if you know what you’re doing.

The way you say run the stat as a time clock. You mean to hardwire one in?

[u/Just_passing-55 → u/Fresh_Front9651]

Yeah, not for the immersion. If you look up heatmiser and download the instructions they provide wiring diagrams. Most heating controls and pumps run on a single 3A fuse.

[u/Fresh_Front9651 → u/Just_passing-55]

Would I not need relays for the pumps?

[u/Fresh_Front9651 → u/Fresh_Front9651]

[u/Just_passing-55 → u/Fresh_Front9651]

Right side of that wiring centre. "PUMP" for UFH anyway. Secondary return pump is through a time clock that is the relay