Welcome to the Piper Boat Owners club Forum. The Forum for owners of Piper built Narrowboats and Barges and anyone interested in Piper Boats. The owners club is completely separate from Piper Boats. Please feel free to post a message to club members and web site readers.
The heating system should be filled with a 50/50 mix of demineralized water and antifreeze. I change mine about every five years and have never had a problem with freezing in a British winter.