Truma FrostControl
The Truma FrostControl is a currentless overpressure safety and drain valve featuring an integrated frost monitor function for Truma hot water systems (Boiler or Combi) and permanently installed water tanks. It automatically drains the boiler contents when ambient temperatures drop below approximately 3 °C to prevent frost damage, and relieves system overpressures up to 4.5 bar.
View official manual on manufacturer's site ↗Technical Specifications
Weight Kg200 g (flexible hoses version) / 250 g (fixed pipe version)
Master Troubleshooting & Diagnostics Matrix
| Error Code / Indicator | Symptom / Meaning | Possible Cause | Step-by-Step DIY Fix | Suggested Actions |
|---|---|---|---|---|
Drain valve (FrostControl) is opening | Below roughly 3°C, the drain valve opens automatically. | — | Switch on the vehicle heater if necessary. Once temperatures at the drain valve rise above approx. 7 °C, it can be closed again. | DIY Safe |
The drain valve (FrostControl) won't close any more | The drain valve's own temperature is below roughly 7°C, or the rotary switch isn't set to 'Operation'. | — | Switch on the vehicle's heater to bring the temperature above roughly 7°C, then turn the rotary switch to 'Operation' and press the pushbutton in until the button engages. | DIY Safe |
The FrostControl discharge nozzle drips water now and then | Water pressure is too high. | — | Check the pump pressure doesn't exceed 2.8 bar - fit a pressure reducer if it's on mains water, to keep the boiler below that pressure. | DIY Safe |
Frequently Asked Questions
Q: At what temperature does the FrostControl automatically open?
The FrostControl automatically opens at ambient temperatures below approximately 3 °C at the valve.
Q: When can the FrostControl be closed again after automatic or manual drainage?
The drain valve can only be closed by hand, and the boiler refilled, once its temperature climbs above roughly 7°C.
Q: What is the maximum pump pressure and system pressure allowed?
The maximum pump pressure is 2.8 bar, and the maximum system overpressure is 4.5 bar.