See the attached file for sizing a pump for your application. If you are looking to replace your existing pump, the part number should be stamped into the suction side of the pump. If you can't find a part number, the gear plate thickness is the last 3 numbers of the part number. For example if the gear plate measures 1/4" (.25") then the pump would be a -250. There are four common Q pump styles, but if you need something different we also stock some other less common styles. The four common ones are:
12171-XXX For use with DC motors. Bearings bled to reservoir (pump mounted inside tank)
12172-XXX For use with AC motors. Bearings bled to reservoir (pump mounted inside tank)
12173-XXX For use with DC motors. Bearings bled to suction (can be used on units with the pump mounted externally like a M-326)
12174-XXX For use with AC motors. Bearings bled to suction (can be used on units with the pump mounted externally like a M-326)
If you are unsure of which pump you need or have any questions feel free to give us a call!
Monarch/Bucher 12172 “Q” Pump
Bearings bled to reservoir
Pressure o ring
Tank o ring
1 needle bearing
4 pump to base mounting screws
Note: Does not come with rear pump o ring #00116. Depending on the configuration of your unit you may or may not have this o ring. Generally all units can and should have this o ring especially vertical mounted units. It can be swapped from the old pump to the new pump.
Commonly used on units such as M-3551, M-319, M-3319, M-326, M-3528, M-3598, M-642, M-631, MAS-3530, MAS-3579, etc.