Room thermostat control
How the TIS Tronic 260U uses a room thermostat on I2 — pump cycling once the room is satisfied, operating and pause times, and the overheat override.
The room thermostat controls the central heating circulation pump, not the fire. When the room is cold the pump runs continuously; when the room is satisfied the controller cycles the pump instead of simply stopping it.
Wiring requirement
The thermostat must be a dry contact on terminal I2, and its logic must be:
- Contacts closed when the room temperature is lower than the user's setpoint → pump runs.
- Contacts open when the room temperature is reached → pump cycles.
For a 24 VAC thermostat, use a 24 VAC SPDT relay. Wiring detail is on Room thermostat.
Inverted logic is a common fault
For correct controller operation you need a thermostat that disconnects the contacts when the room temperature is reached and connects them when it is lower. Verify with a meter.
Parameters
Enables or disables the room thermostat function.
How long the circulation pump runs during each cycle once the room temperature has been reached.
| Range | 30 … 250 seconds |
| Factory default | 30 s |
The pause between the next circulation pump start-up. Active only when the room temperature set on the thermostat has been reached.
Setting this to 0 makes the circulation pump inactive — that is, it stops completely when the room is satisfied.
| Range | 0 … 240 minutes |
| Factory default | 1 min |
Why cycle instead of stop?
Cycling keeps the emitters and the distribution loop from going cold and stratifying. With a 30 s run every 1 min, water keeps moving gently, so:
- the room temperature stays even rather than sawtoothing;
- the boiler's return temperature does not crash, which protects it from condensation;
- and heat continues to leave the boiler, which is important on a solid-fuel appliance you cannot simply switch off.
Set the pause to 0 only when you have another path for boiler heat — a buffer tank or a hot water load.
Overheat override
The thermostat is ignored when the boiler is hot
If the boiler temperature exceeds the maximum boiler temperature value (MBtek recommends 80 °C / 176 °F), room thermostat control is switched off to protect the boiler from overheating. The pump will run regardless of what the thermostat asks for.
This is deliberate. A wood fire cannot be turned off, so the controller must always be able to move heat out of the boiler.
NextQuenching and fuel shortageHow the controller decides the fire has gone out, and what it does then.
Hot water (HUW)
Configure domestic hot water on the TIS Tronic 260U — Summer and Winter modes, HUW priority, hysteresis, working hours and the boiler temperature increase function.
Quenching and fuel shortage
How the TIS Tronic 260U detects that the fire is out — by boiler temperature or exhaust gas temperature — and what it does with the fan and the central heating pump.