Frost is one of the biggest risks to the water system in a motorhome or Camper Van. Even slightly sub-zero temperatures can damage boilers, water tanks or water pipes. A frost monitor (the colloquial term for a safety and discharge valve in your motorhome’s water system)reliably protectsthe system from frost-related damage.
If the frost monitor (safety and discharge valve) cannot be closed, this is usually due to the temperature or the installation conditions.
Here’s how to do it, step by step:
1. Check buffer position
The frost monitor only closes directly at the valve when the temperature is above approximately 7 °C. If it gets colder, the valve stays open automatically to prevent frost damage. In most cases, this is not a technical fault, but a direct result of the current temperature at the frost monitor.
Heating the interior: Heat the area around the valve to above approx. 7 °C – then wait for approx. 15–30 minutes, after which the push-button will click back into place.
Note: The frost monitor is often positioned close to the floor – where it is colder than in the living area. Alternatively, heat the area around the frost monitor specifically (e.g. with hot air).
The location of the safety/discharge valve varies depending on the model. Please refer to your operating instructions for the exact position of the valve. For motorhomes, the location of the safety/discharge valve can be found under the heading ‘Location of the safety/discharge valve’. In Camper Vans, the frost monitor isusually locatednext to the heater, under the bench seat.
2. Close the valve properly
As soon as it’s warm enough:
Turn the (1) dial to ‘Operation’ . Set it to ‘Operate’ before pressing the push-button.
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Press the button (2) – which is usually blue – firmly until it clicks into place. If the button doesn’t click into place, it’s almost always still too cold.
Image: Safety and discharge valve open
Image: Safety and discharge valve closed
3. Check the installation position and mobility
Check that the frost monitor is easily accessible .
Check whether dirt, limescale or deposits are blocking the valve.
Carefully operate the valve several times (do not use force).
4. Switch off the water pump
Before closing:
Switch off the water pump
Turn off all taps
Check the water pressure: If water is leaking even though the valve is closed, this may be due to excessive water pressure. Use a pressure regulator if necessary. This will help you avoid back pressure, which can make closing more difficult.
5. If it still doesn’t work
Valve does not close despite the heat → possible fault
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In this case:
Contact a dealer or service partner
Have the frost monitor replaced if necessary
Abstract
✔ Heat to above 7 °C
✔ Turn the blue knob + press the push-button
✔ Pump off, no back pressure
✔ If the problem persists: Contact Customer Services/Dealer
See also: What is a frost monitor in a motorhome?
In your vehicle’s operating instructions , we answer many of your questions about our vehicles. There, we explain step by step how our vehicles work and how the standard accessories are used.
If you have any questions, please do not hesitate to contact your contract partner. You can find a list of all Carado dealers easily and conveniently using our dealer search.