Gea grasso pulse pump

[mizar]

hello evverybody

i have a unit with a old style grasso pp35 pulse pump old.jpg where they are using all 3 ports on the lucifer magnetic valve. too control the gas activated valve for oil return from evaporator.

the normal port 1 & 2 running straight thru is used too activate valve and the port 3 in the top i dont now why they are using it is mounted on the other side of the gas activated valve as i recall i mean there is a spring in that valve too close when you are finished with oil return cycle. ( between port 1 & 3 there is connection when valve is closed so thre is running high pressure gas thru a nozzle and in too the evaporator but i havent seen this before.

but on the later grasso units they are just using 2 way valves too control the gas activated valve on the pulse pumps new.jpg so my question is can i convert this and block the 3 port and mount an 2 way valve
because my client is a bit tired if we have to change the coil so we have too drain the unit .