After fetching the motorhome from storage I filled with water and found the Truma drain/frost valve will not close. Despite the 'pop out' button being in, water is draining out. I have tried repeatedly turning the top switch 90degrees but the pop out button does not pop out and the water continues to drain.
Anyone got any suggestions ? I have run the heating for about half an hour in case it was too cold. I guess air temp was about 6/8 degrees today.
Paul.