Quick Answer
Using an undersized pressure tank can lead to reduced water flow, increased pump wear, and potentially catastrophic failures such as tank rupture or pump burnout, resulting in costly repairs and downtime.
Inadequate Pressure
An undersized pressure tank is unable to store enough water to meet the demand of a household or commercial system. This can lead to a drop in pressure as the tank drains, causing water flow to decrease. For example, a typical household uses around 10 gallons of water per minute for a shower. If a tank is sized for only 30 gallons, it would need to refill every 3 minutes, resulting in a significant decrease in water pressure.
Increased Pump Wear
When a pressure tank is undersized, the pump must work harder to maintain adequate pressure, leading to increased wear and tear on the pump and motor. This can result in premature failure of the pump, motor, or both, requiring costly repairs or replacement. To determine the required tank size, calculate the total system demand in gallons per minute (GPM) and multiply by the desired pressure differential (e.g. 30-60 psi) to determine the required tank volume in gallons.
Potential Failures
In extreme cases, an undersized pressure tank can lead to catastrophic failures such as tank rupture or pump burnout. When the tank is unable to store enough water, the pressure can become too high, causing the tank to rupture or the pump to overheat and fail. To avoid these risks, it is essential to properly size the pressure tank based on the total system demand and desired pressure differential. A general rule of thumb is to size the tank for at least 2-3 times the system demand in GPM.
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