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This article describes how to diagnose the loss of and need for air in a water tank, how to add air to a building water pressure tank, and how to detect and correct air and water leaks in a building water supply system where a private well is the water source. We also discuss how to adjust the building water pressure by setting the cut-in and cut-out pressure on the pump pressure control switch. Several alternative procedures for adding air to a water pressure tank are described below along with advice about what to do when things go wrong, such as finding air and water leaks. The illustration at page top is courtesy of Carson Dunlop, Inc. in Toronto.

Short cycling of a water pump (which is discussed in this article) means that the water pump turns on and off too rapidly or too frequently when water is being run in the building. If this is the problem with your water pump, see SHORT CYCLING CAUSES

Intermittent water pump cycling which is discussed at Intermittent Water Pump Cycling When No Water is Running means that the water pump comes on for no apparent reason.

Loss of water pressure means that the pressure with which water enters a plumbing fixture has become too slow, or is sometimes too slow or weak in water flow rate, or water flow may stop entirely. See WATER PRESSURE LOSS DIAGNOSIS GUIDE

© 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

WHAT IS SHORT CYCLING - Introduction: What is "short cycling" of the water pressure tank and why can it be harmful?

The "water storage tank" is doing more than storing water. Its air charge acts like a spring to smooth the delivery of water in the building. If the building water supply pump is "short cycling" - coming on and off rapidly, you may need to add air to the water pressure tank. This step is important to protect your private pump and well from damage due to short-cycling due to loss of air in the pressure tank. Short cycling of the pump motor can burn up the pump relay control.

The minimum that a building owner or occupant needs to know is that short cycling is an on-off cycle of the water pump in a house with a private water pump and water supply well system. The "short cycling" water pump is turning on and off rapidly, perhaps every 10 to 20 seconds or even more frequently. Water pump short cycling can damage the pump or controls. Repair is needed at one or more of: the water pressure tank, water pump pressure control switch, water pump, water filter, or the well or building water supply piping. If you are not interested in tackling this easy repair yourself, call a plumber.

The sketch shown at the top of this page shows the components of a typical residential water well, water pump, water pressure tank, and water pump control system. Below we include other drawings and photographs of wells, water tanks, and their associated valves and controls. At some properties the well pump may be inside rather than in the well as in this drawing, and on your tank the water pressure gauge may be mounted on a special air volume control fitting on the back of the water tank itself rather than as shown in this sketch. Sometimes people think this water tank is to "store" water for use in the building. That's rarely the case. Usually water is "stored" by being present in the well and in the ground around the well.

If a pump-operated water supply system is turning on and off rapidly (every few seconds) it would be smart to turn off the water or turn off electric power to the water pump and call a plumber promptly.

DETECT SHORT CYCLING - How do we Detect Short Cycling of a water pump? What do we do?

Normally the "pump on" cycle is 30 seconds to 90 seconds or longer, depending on water tank size, and the "pump off" cycle is the same or longer.

What is Water Pump or Water Tank "Short Cycling" - rapid on and off water pump

Short cycling of the water pump means that the water pump keeps turning on and off rapidly whenever you're running water at one or more fixtures in the building. The pump on-off cycle may be perhaps every few seconds, or perhaps every 10-20 seconds. This is a problem, which we diagnose, discuss, and for which we offer repair procedures below. The minimum that a building owner or occupant needs to know is that short cycling can damage the pump or controls, and that action is needed.

These short cycling problems happen with both in-building jet pumps and with in-well submersible pumps. It's trickier to notice a short cycling submersible pump since you won't hear the pump motor, but you will hear the pump relay clicking on and off, or you can see the water pressure gauge cycling up and down rapidly.

If you are not interested in tackling this easy repair yourself, call a plumber. If the system is turning on and off rapidly (every few seconds) it would be smart to turn off the water or pump and call a plumber promptly since if you let this problem continue you're likely to damage a pump control or pump motor (expensive).

You can tell if your water pump system is "short cycling if:

• Water pressure pulses, that is the pressure goes from strong to weak, at a short time interval ranging from just a few seconds to perhaps a minute.
  
  
• The water pump turns on and off rapidly, on the same time interval. You may hear the pump motor running and stopping and running again.
  
  
• The water pressure gauge oscillates from high to low pressure rapidly on the same time interval. You can use this method if your well pump is not located in the building where you can hear it. The pump itself may be outside in a well pit or down in the well itself (a submersible well pump).

If you don't know how to find your pump pressure gauge, pressure controls, switches and controls, see WATER PUMP & TANK CONTROLS & SWITCHES

How to Detect a Short Cycling Water Pump and Tank

We give more description of how to detect short cycling of the water pump at SIGNS OF AIR LOSS

How to Fix a Short Cycling Water Pump and Tank

We describe how to correct water pump short cycling, in great detail and giving several methods, at WATER TANK AIR, HOW TO ADD for conventional water tanks that do not use an internal bladder. \

Bladder type or captive-air water pressure tanks and their repairs are described at WATER TANK TYPES and at WATER TANKS HOW THEY WORK.

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PLUMBING TOPICS
OIL TANKS
SEPTIC SYSTEMS
WATER PRESSURE REGULATOR ADJUST
WATER PRESSURE REPAIR GUIDE & COSTS
WATER PRESSURE LOSS DIAGNOSIS GUIDE
WATER PRESSURE & FLOW MEASUREMENT
  WATER PUMP PRESSURE CONTROL ADJUSTMENT
  WATER PUMP PRESSURE CONTROL REPAIR
  WATER PRESSURE REGULATOR ADJUST
WATER PUMPS & WELL TANKS
WATER PUMP CONTROLS & SWITCHES
PUMP TYPES & LIFE EXPECTANCY
WATER PUMP & TANK SAFETY
WATER SUPPLY & DRAIN PIPING
WATER TANK TYPES: WATER, OIL, EXPANSION, ALL
WATER TANK LIFE EXPECTANCY
WATER TANK REPAIRS
  CONTROLS & SWITCHES on WATER TANKS
  INTERMITTENT CYCLING WATER PUMPS
  WATER PUMP SHORT CYCLING
  SHORT CYCLING DETECTION
  SHORT CYCLING CAUSES
WATER TANK AIR, HOW TO ADD
  WATER TANK AIR LOSS SIGNS
  WATER TANK AIR VOLUME CONTROLS
  WATER TANK AIR ADD AT AIR VALVE
  WATER TANK AIR ADD BY DRAINING
  WATER TANK AIR HOW MUCH TO ADD
  WATER TANK AIR HOW OFTEN TO ADD
WATER TANK BLADDERS & CAPTIVE AIR
WATER TANK REPLACEMENT
WATER TANK BLADDER PRESSURE ADJUSTMENT
WATER TANK PRESSURE CALCULATIONS
WATER TANK SIZE & VOLUME
WATER TANKS HOW THEY WORK
WATER TESTING
WELLS CISTERNS & SPRINGS

• Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.

WATER PRESSURE LOSS DIAGNOSIS GUIDE
WATER PRESSURE & FLOW MEASUREMENT
  Water Pressure Intermittent
  No Water Pressure
  Water Pressure Tank Problems
  Water Pressure Tank Diagnosis
  Water pipe clog diagnosis
  Water pipe clog repair guide
  Making the "right" repair
  Typical Water Tank & Pump Prices.

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