i've got a 22mm coil in the hot water cylinder, this gets fed from the central heating boiler and a hot tube ( instead of the electric heater ), this is from the wood fired boiler. i have one 15 mm boss ( low down) left on the tank , but know of no device which would fit, being just 15mm. i would use this in the summer months when neither boiler is on.

zephania, October 2009

no, that hole is for a drain tap to fitted, so is too smal for any use.

erj, October 2009