Quick Answer
Cycling too often usually indicates inadequate water pressure tank sizing. A larger tank may be needed to hold more water and reduce the frequency of tank cycling. Proper tank sizing should be determined based on the pump's flow rate and the household's water demand.
Assessing Current Tank Size and System Demand
To address the issue of a cycling pressure tank, the first step is to assess the current tank size and the demand placed on the system. Measure the flow rate of the pump in gallons-per-minute (GPM) and calculate the total daily water demand of the household. A general rule of thumb is to size the tank to hold 2-4 gallons of water per gallon-per-minute of pump flow rate. For example, a 2 GPM pump would require a 4-8 gallon tank.
Calculating Demand and Sizing the Tank
Calculate the daily water demand by multiplying the number of occupants by 50-100 gallons per person. Add the demand of appliances such as toilets, washing machines, and dishwashers. For a household of four, with two 1.6 GPF toilets, one 2 GPM washing machine, and one dishwasher, the daily demand would be around 300-400 gallons. Based on this demand, a 20-30 gallon tank would be needed for the 2 GPM pump.
Upgrading the Tank or Modifying the System
If the existing tank is undersized, consider upgrading to a larger tank with a capacity of at least 20-30 gallons. Alternatively, modify the system by installing a larger pump or upgrading to a variable-speed pump that can adjust to changing demand. This will ensure that the tank does not cycle too often and provide a consistent water supply to the household.
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