[john martin]

Im not breaking down in the christmas rush with my two pumps   

Really though its about providing much more flow when using a four jet wand for example  , but u can see a big difference even with a 6flow total  two jet as it maintains its pressure with the incresed flow .
So two aquatec 250psi diaphragm pumps in parallel , with a selector switch for one or both t same time ... im flicking the switch a few times in the vid

https://vimeo.com/302926104

[JandS]

Why not just buy a bigger pump with variable flow....mine goes up to nearly 450psi but have had it as low as 60/70 with Drymaster tool on.

[Robin Ray]

Why not just buy a bigger pump with variable flow....mine goes up to nearly 450 psi but have had it as low as 60/70 with Drymaster tool on.

I have to agree, I have 800 psi and never go above 450 psi, and for upholstery with the sapphire im down to 50 - 60 with the flow controller on the tool turned down.

Whats the advantage over having a 400 psi to 500 psi pump?

[john martin]

well its just an example of something else that works  ,  its not my idea , a chap in the states used it first  and i wanted to try it .
I would now have the flow of a very big pumptec  , about 2.5gpm id say .
Advantages might be ...   less weight  ,  less current draw  , which is great for me as i rum two 6.6 on the same cord as the pump .
Diagraphm pumps need no priming before u start , can run dry .less fussy in general .

It works for me anyway , if just detailing with my single jet wand or doing upholstery the single pump if all i need , but if i have to relly flush something  bad the second pump makes all the difference and you use larger flow wands without the pressure drop at about 200psi .

[MarkSutcliffe]

well, thats tempting to try.. :p

[john martin]

well, thats tempting to try.. :p

Hi , if doing it  ...     my pump type has no electric demand switch  ...  so coming off the output hose of each pump i have a non return valve ...  bit like this ( there are various designs ) 
https://www.amazon.com/Check-Valves-Valve-Threaded-Female/dp/B07DY2RBBX

This is just incase the pressure from one pump running   damages or leaks into the second pump when one if off .

The guy in the states that runs this setup has the pump with the demand switch and  he didnt bother with check valves , as he dosn't switch one pump off either .