Suitable for use with both the Tankmaster Mark I and Mark II.
Please note: The product being sold here excludes the hand-wheel and the circlip shown in this cut-away picture to help advise on the functioning of the valve in the centre of the Atkinson Tankmaster (as per the top picture).
The hand-wheel has a left-hand thread so when this is turned clockwise it comes out of the threaded union and starts to free-wheel. The valve is now in the closed position as it is sprung loaded to default to closed. When the hand-wheel is turned anti-clockwise (it may need to be pushed in slightly to 'catch the thread') this is driven inwards and the centre shaft is also pushed inwards thus opening the valve to allow the oil to flow out of the tank.
A number of reported problems over the years (outside our control) with the opening and closing of the valve include:
a) the 'O' ring under the valve seat to the oil tank has come off (this can happen when PTFE tape has been allowed to run off the end of the threaded male inlet section) preventing the valve from closing properly to shut off the flow of oil;
b) a bit of 'crud' has become lodged between the 'O' ring of the valve and the body of the union thus preventing the valve to closing properly to shut off the flow of oil;
c) this has been installed using the wrong tank-adapter, which physically prevents the valve from opening at all;
d) the hand-wheel bell-housing connection to hand-wheel threaded section has become corroded and broken adrift preventing the hand-wheel from controlling the flow of oil (i.e. turning the hand-wheel bell-housing does not turn the hand-wheel threaded section).
Occasionally we have had customers come on the phone saying that their installer has advised them that the central shaft of the valve has broken. This has never happened and is a most unlikely event because it is made of solid brass that is 6mm in diameter.
Tip: This can only be fitted safely when the oil tank is empty as this is the main control valve that prevents the flow of oil from the tank.