Prevent Expensive Diaphragm Damage with This Easy Tip

Prevent Expensive Diaphragm Damage with This Easy Tip

Posted by andrew greess on Sep 12, 2022

Diaphragm pumps are great pumps for many spray applications such as weed control, landscape, pest control, etc.

The main benefit of diaphragm pumps is that they can pump almost any type of material, including abrasive materials such as granular fertilizers.  Diaphragm pumps can also offer higher pressures required to reach tall trees and throw water long distances.

At we stock Annovi-Reverberi AR Diaphragm pumps and parts.   These are top quality pumps used on many of our power spray rigs.    AR is the company that built the familiar Hypro AR253, AR30, AR50 and other diaphragm pumps.  AR and Hypro have severed their relationship and Hypro now has new models of diaphragm pumps.


Diaphragm pumps require the operator to pay attention.  Most diaphragm pumps have an oil reservoir.  The oil reservoir shows the operator the condition of the oil in the pump.  The oil in the pump serves a purpose much like the oil in your car.  It keeps the moving parts lubricated.


See the oil reservoir on this AR30 diaphragm pump.  It is a clean, clear slightly yellow liquid.  This is exactly what it is supposed to look like.

It is critical that technicians check the oil reservoir BEFORE starting the engine.  This check is necessary to ensure the oil is in good condition in the pump.  The technician should also be doing other checks such as checking the filter to make sure it is not clogged.  Clogged filters prevent water from getting to the diaphragm pump.  A diaphragm pump can run for a short time without water.  Eventually it will get too hot and bad things start to happen.

Examples of bad things:  diaphragms burst, oil runs out of pump, pump runs too hot. metal parts start to melt and fuse, pump is destroyed.

Here is an example of a pump with burst diaphragms.  All the oil has run out of the pump and it is replaced by whatever it is the technician is spraying.  You can see the clean, clear oil has been replaced by milky water-based material.

If the tech stops immediately when the diaphragm burst, then all that is required is to replace the diaphragms.  We recommend proactively doing pump preventative maintenance to prevent burst diaphragms.  If the diaphragms do burst, there are warning signs.  The tech will hear a change in the sound the pump is making and will sense a change in pressure.  It the tech stops immediately, the pump can be saved.

Here is a photo showing what burst diaphragms look like:

It appears the pump was run for a significant time after bursting, because the diaphragms are in such bad shape.

Here is a photo of a diaphragm pump from a landscape power sprayer that was completely destroyed because the tech ran the pump for too long after diaphragm failure.

You can see bits of metal (probably bits of connecting rods, etc.).  This pump was a total loss and an expensive problem for the owner.  This problem is completely preventable.  Perform power sprayer preventative maintenance either at end of season or before the new season.  Train and retrain techs on proper sprayer operation and how to identify and prevent power sprayer problems like these.