I've got a CAPA 9 psi Powerdyne kit for my EF I6, but I think this question is universal to all CAPA kits.

It's come with two boost/vacum sensors, one for the water injection and one for the second fuel pump.

The first is 'Switch Vacum (NC)' (http://capa.com.au/capa_performance_hoses.htm) - this is for the fuel pump:


The second is 'Hobb Switch Boost / Pressure (No)' - this is for the water injection:



Can anyone confirm for me how these work?

I assume the Vacum Switch for the fuel pump senses vacum. When it senses vacum it doesn't run the second fuel pump. So any time when there isn't any vacum (i.e. there's boost) it will run the second fuel pump?

And the boost/pressure Switch for the water injection I assume does the opposite, in that it sense boost. So any time when there is boost it will run the water injection, but when there is no boost (vacum) it will not run the water injection?

They say the Boost Switch for the water injection is adjustable by removing the rubber cap on the top and using an alan key. Using a boost gauge and air compressor to adjust it.
The vacum switch for the fuel pump also has a rubber top cap, but it is different inside, no alan key fitting - so I assume it is not adjustable.

They both work exactly the same way, except the electrical part.

The bit at the end NO and NC denote what type of switch is used.

NO = Normally Open (off)
NC = Normally Closed (on)

So when there's no boost, one switch is off (NO), the other one is on (NC). When boost activates the internal switch, they change state. The NC (on) turns off, and the NO (off) turns on.