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Common Diaphragm Pump Problems and Their Solutions

Diaphragm pumps offer a cost effective solution to delivering a large volume of coatings at a relatively low cost. They are also relatively simple in design consisting of a gasket like diaphragm that air causes to switch back and forth and in the process of doing so moves material into and out of the pump. Given all their benefits a diaphragm pump makes a lot of sense. However, if your having problems with your diaphragm pump it can quickly become a solution you do not like. This guide will cover common diaphragm pump problems and their solutions. Please note if your regularly having problems with your diaphragm pump, you may want to evaluate if the pump was properly chosen for your application.

Common Diaphragm pump problem # 1 – Fluid is delivered inconsistently

A common problem that is mentioned with a diaphragm pump is an issue called a wink. A wink is seen when the material comes out of a diaphragm pump at an inconsistent pace. This can be problematic especially if your diaphragm pump is being used in an application where consistency in fluid delivery is important, like in painting. A wink coming from a diaphragm occurs when the air diaphragm switches from using one half of the pump to the other resulting in a brief change in fluid volume output which results in a slight wink. This is actually not a problem but more of a common challenge with a diaphragm pump. If your diaphragm pump winks when you are using it and this is problematic, you can consider a fluid outlet regulator. A fluid outlet regulator evens out the pressure at which material exits the diaphragm pump to your spray gun or through the system. By regulating the fluid output pressure the fluid will be consistent as it reaches the end of your fluid line on your diaphragm pump which will eliminate any winks that you may see.

The other potential issue that can create inconsistent fluid delivery is the diaphragm inside your pump has worn. Over time the diaphragm can wear down and even rupture. When this happens the pump will not move evenly side to side which can create uneven fluid delivery. Typically when this happens the pump will move relatively slow to one side and then rapidly move to the other. While it may be the diaphragm it could also be the ball and seats in the diaphragm pump (see photo below for greater detail on problem areas please note the photo doesn’t show ball and seats). Ultimately if the pump moves unevenly on one side, the diaphragm, air check valve, or ball and seats in the pump are probably worn too much or not clean and as a result, will not have controlled even delivery of material when the pump moves from one side to the other. The right steps to solve this if it is occurring is first to try to ensure your ball and seats are clean.  Second, review the diaphragm for any tears, and finally if both seem to be working well consider that the air check valves are too worn. If any doubts you can rebuild each component or contact us for additional help troubleshooting.

Diaphragm pump problems and solutions

Common Diaphragm Pump Problem # 2 – My pump breaks down excessively

If your constantly rebuilding your diaphragm pump, this is typically a sign that your diaphragm pump is working too hard. Diaphragm pumps are specified with a maximum working fluid delivery rate. However, this maximum rate is a bit misleading because it is showing the fastest the diaphragm pump can possibly go. Most of the time you want the actual GPM that the diaphragm pump is operating at to be about 40 – 50 percent of its maximum GPM ability. This will result in the pump moving slower and help improve the life of the pump.

Common Diaphragm Pump Problem #3 – My pump freezes and becomes Stuck

Another problem that occasionally happens with diaphragm pumps is that the diaphragm can become stuck as it attempts to switch from being on one side of the pump to the other. While this was a lot greater issue when diaphragm pumps first came out, over time it has been addressed greatly. However, if you find this issue occurring routinely it can again be a good time to review the internal diaphragms as well as the air check valves with the pump that control air delivery to each side of the pump and create the back and forth motion that keeps the pump working. You may also need more CFM of air to operate the diaphragm pump. If the pump physically freezes this also is typically an indicator that your diaphragm pump is being overworked. This typically happens when the GPM of the pump is not enough to support your application.

Final thoughts

Ultimately a diaphragm pump is a durable solution for fluid delivery. Common problems that can occur are typically related to the ball and seats in the diaphragm pump, a worn diaphragm, or worn air check valves. Otherwise, it may be that the diaphragm pump that has been chosen is not large enough for your application or doesn’t have the proper accessories like a fluid regulator to keep uneven fluid delivery. If you need additional help with a diaphragm pump you can contact us.

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