Arrows will be on the brass body of the valve, the plastic head simply attaches to the body, operating a pin which in turn opens/closes valve as required. The other end should have 'standard' rad valves fitted, with a small plastic cap to cover the spindle.
There is no standard for which side of a radiator the valves are fitted, but some Thermostatic Radiator Valves (TRV's) will only work 'one way', i.e. the water needs to flow through the valve in the direction specified by the arrow.
There is no standard for which side of a radiator the valves are fitted, but some Thermostatic Radiator Valves (TRV's) will only work 'one way', i.e. the water needs to flow through the valve in the direction specified by the arrow.
