It comes with a Vacuum actuator, which I didn't want, but it is easily removed, see picture. It should also be pretty simple to make up a bracket to fit a Bowden cable, solenoid or other actuator in the future. The Lever in the middle isn't spring loaded so can easily be switched On/Off by hand.
So far have just ensured I have no leaks and it works, ie the heater inlet pipe does not get Hot with the Bypass On, but does get Hot with it Off.
The Inlet pipe does go up in temp a little! Could be a leak from the valve letting small amount of water through or just the heat from the engine bay, Have to let the system cool down now so will continue the Air Temp test when all is cooled again and post results here.
Obvious issue here is that the lever not being spring loaded, and in the absence of a positive actuator , the valve is not being held firmly in the closed position. You don’t need much of a gap to allow enough water to flow to warm up the heater.
As an example, if you shut the valve off on your household radiator, then just very, very slowly turn it until you can only just hear water flowing, you will find the inlet pipe gets hot very quickly. At this point, the valve seal has only just lifted off its seating by a whisker.
So fit a Bowden cable or similar and I think it will be much better. As a test, you could apply an elastic band or a spring to the lever to see if it makes a difference.
