VT Pump Check Valve Instructions (VT4923 & VT4823)

VT style pumps w/ 2 air lines in head

These instructions are if your old pump had 2 air lines in the head; one for the air going to the tank and one going to the unloader on the side of your pressure switch.
The new style pump only has 1 air line hole in the pump head which supplies air to your tank.
To be able to make your motor start easier, the head pressure must be relieved from the large air line to your tank prior to each cycle that your motor comes on.
To do this, you must convert your old tank check valve, (the big nut at the bottom of your air supply line from your pump into your tank) which does not have a 1/8” port on the side as the new one does.
You will replace item 11 above with a new check valve, the CV221800AV below, which has a 1/8” port on the side to attach the tube kit, MP513901SJ

to the unloader valve on your electric pressure switch as shown below.
Now, every time your motor cuts off, your pressure switch unloader valve, above, will relieve a small amount of air trapped in the big supply tube. This air will travel down the small air line, from the check valve location to the unloader valve above on your pressure switch.