What is this thermostat?

[rwski]

I’m trying to come to grips with our central heating system so we can add ufh and more sophisticated controls for the existing radiators.
This thermostat (white thing with black dial) turns the pump (running 2 radiators and a towel rail) on when the temperature from it’s probe in the tank is higher than the temperature on the dial. So shown here, if the tank temperature (in the middle) is more than 40°C the pump runs. We obviously have an open loop (through a towel rail) to cope with this basic level of control.

The person who installed the system (this was some years ago) suggested we could use heatmeiser eventully, so I’m trying to understand (at a high level) how this would work with a wiring center.
My question is, if I want to replace this thermostat with something heatmiser that I could see the temperature of the probe as well as have the same functionality what might it be?
Also I would want to take this output into the wiring center so that the ufh (and radiators) would only run if the tank had sufficient heat. Where would this go? Do I need to combine the output of this thermostat (and) with all the room thermostats so they only input a call for heat if both outputs are positive? Or I can input somewhere else? I see there are some hot water inputs but I think they relate to dhw.

The heat input is solar thermal and a wood gasification boiler, so if the tank is too cool we need to manually do something, we don’t have a boiler to fire up automatically. A wiring diagram for a similar system would be amazing if someone has such a thing…

Thank you for any help (at the moment I am trying to understand what is possible because otherwise it is difficult to find people to do the work - or even to help us do it. You can see my knowledge of heating is fairly rudimentary but I want to learn!)

 

[ianmcd]

It isnt a thermostat as such

Differential controller KSW-E with 2 sensors TF/Pt

Differential controller for the control of solar systems in combination with hot-water storage tanks. The controller provides a graphic surface and a start-up assistant for simple operation. The integrated data logger records all controller settings, system functions and excessive temperatures...

www.oeg.net

 

[rwski]

Sorry my question and photo weren’t v clear! Yes that is the thing that controls the solar thermal loading to the tank, I meant the thing below and to the left of it, which conteols whether the central heating oump runs or not - taking heat from the tank…
Sorry!

 

[Madrab]

That's the cylinder stat, it monitors the cylinder temp usually that would create the heat source demand once the temp in the cylinder drops below its set point.

 

[rwski]

Ok good to know it is just normal thermostat, there is no brand or anything on it so couldn’t look up characteristics). At the moment it turns on the central heating (so heating is on when thermostat is set lower than tank temperature), I suppose via a relay somewhere.
We’d like to input the output of this thermostat to the wiring center of UFH so that UFH would only run when the tank has enough heat. The boiler is wood, so it doesn’t fire automaticlly. Any ideas whether we can do that on any wiring center and what the wiring diagram might look like?

 

[Madrab]

As part of the system plan that you will have, the thermostat will be part of the HW circuit. When the programmer is calling for HW, the live signal form the programmer is sent to the thermostat, if the cylinder is below the set temp then the thermostat sends that live back out and into the (presumably) 2 port valve. That live activates the valve and as the valve opens it activates an internal microswitch which sends a live out to the boiler, firing it up.

 

[rwski]

So it is basically the HW stat in this diagram and none of the calls for heat from the room thermostats would result in an actuator opening until the HW stat was closed. And in this diagram the boiler would run, but for us it wouldn’t because we have to fire it manually…

 

[Madrab]

So it is basically the HW stat in this diagram and none of the calls for heat from the room thermostats would result in an actuator opening until the HW stat was closed. And in this diagram the boiler would run, but for us it wouldn’t because we have to fire it manually…

Yes it would be that stat but the system should be able to run with either calling, or all calling, unless it's setup as HW priority.

If it is, in essence, an S Plan then both the CH, UFH and HW could all be run at the same time.

With the UH8-RF, either the stat(s)/actuator(s) or the HW can call for heat, that call then opens up either the HW 2 port valve or the Rad 2 port (UFH 2 port) and those valves then sends a switched live to the boiler.

 

[rwski]

We don’t actually have a boiler to call to, and hot water can run all the time and won’t be connected to the wiring center (as it is a coil through the thermal store run on mains pressure), it will be more or less hot depending how much heat is in the store (depending on solar thermal input or wood burner input).
It sounds like if we set HW priority it would do what we want if I understand right. Which is only run the UFH if the tank is above a certain temp…
Would a different wiring center work better? Are there ones that are aimed at thermal stores. We have other Drayton Wiser and would like to use that one ideally but it may or may not be suitable I guess…