Bubbles in the water gauge glass has always been a problem on the smaller locos so it was decided to fit a blowdown valve on one of the rebuilt Mamods to see if it would solve it.
Method chosen for the tiny Janet boiler is based on the system used on Accucraft Sabrina (enormous boiler) where the valve is on the other side of the cab to the gauge glass.
- Purchased a 1/4 x 40 1/8 Pipe 90 degree globe valve from Macc Models
- Drilled a 1/8 hole in the lower fitting of the sight glass unit
- Soldered a 1/8 copper pipe into the hole and ran it from there to the input side of the globe valve
- Ran a further 1/8 pipe from the output side of the globe valve and vented it through a hole in the footplate
