How do you drain the radiators?
QHave you any advice to give on the best way to drain a boat’s central heating system that comprises a Mikuni MX40 and three radiators? The lowest part of the system is at floor level so a bucket to collect water seems impractical. Incidentally, I enjoy reading your expert advice section of the magazine and have picked all manner of tips and ideas from it.
website TONY REPLIES... First, trace the pipes closely through the boat. Sometimes a pipe extends into the engine bay with a drain cock on the end (pictured right). You could also find a drain cock low down somewhere else in the system.
A drain cock has a barbed fitting on it for a hose. I have two on my system so that, with the aid of a drill pump, the liquid in the system can be pumped into containers for proper disposal.
Remember that antifreeze is classed as a hazardous substance and should only be disposed of at refuse sites with the facility to collect it.
If you have neither on your boat then I fear it is a case of seeing whether an oven roasting tin or perhaps fairly shallow plastic containers will fit under a pipe union so you can loosen the union and slowly drain the system that way. If you are forced to do this,
AI would advocate fitting a drain cock when the system is empty. You can often replace an elbow feeding the last radiator in the system with a tee piece and fit the cock to one arm of the tee.