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This article describes Water tank pressure gauges, how to read, use, repair or replace water pressure gauges. Readers of this document should also see WATER PRESSURE GAUGE ACCURACY and see Water pump and pressure tank repair diagnosis & cost an specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost.

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WATER TANK PRESSURE GAUGE

In this photo the water tank pressure gauge is visible mounted on a special brass fitting which is in turn connected to the bottom of the water pressure tank. The water tank pressure gauge is showing about 37 PSI. Note that water tank pressure gauges give a general idea of the water pressure measured at the water tank, and that the pressure shown on the gauge will normally drop down to the "pump cut-in pressure" at which point the water pump should start operating, and the gauge pressure will then rise up to the pump "cut out pressure" when the water pump stops. Water Pressure Indicator Gauge Accuracy Typical residential water system pressure gauges found at the water tank or water pump are only approximate and are not lab instrument grade, but the water pressure gauge is a very helpful diagnostic when you're diagnosing a loss of water pressure or pump operating problem as well as when you're adding air to a water tank. See WATER PRESSURE GAUGE ACCURACY for details.

How to Repair or Replace the Water Pressure Indicator Gauge on a Water Tank or Pump

How to Replace a Broken Water Pressure Gauge, or How to Correct A Water Pressure Gauge that Reads too High or Too Low

If the water pressure gauge glass is broken or missing, if the gauge is visibly rusty or damaged, or if the gauge simply stops changing what it indicates despite the water system pressure changing (in other words the pressure shown on the gauge never changes) you should replace the gauge itself.

The well pump is turned off, pressure is drained from the system (you do not have to let all of the water out of the tank, just be prepared for a little spillage). Then the new water pressure gauge is prepared for installation (make sure the gauge bottom threads match those of the old unit being replaced as diameters vary from 1/4" to 1/2").

• Turn off power to the water pump and drain most or all water pressure from the system.
• Have at hand a new water pressure gauge of the proper pressure sensing range - and be sure that the pipe thread diameter of the gauge mounting base is the same as that on the old gauge so that you won't also need an adapter to mount the new gauge in the old position.
• Prepare the new pressure gauge mounting threads by wrapping with teflon tape or applying pipe joint sealing compound - keep the compound away from the opening at the bottom of the gauge through which water passes, or you may clog your new gauge early. We put our teflon tape or pipe dope on the new gauge threads before trying to remove the old gauge. Then the old gauge is removed by using a wrench on the brass fitting at the bottom of the gauge.
• Use a wrench on the brass base of the old gauge to unscrew it. DO NOT try to remove a water pressure gauge by twisting the gauge body itself - you'll just break it off and you may get cut or start a water leak.
• Remove the old water pressure indicator gauge. Clean any debris around the gauge mounting hole - or water squirting out may do this for you.
• Calmly screw in the new one even though water is flowing out of the gauge mounting hole. Screw in the new gauge first by hand to be sure that you are threading it correctly don't "cross" thread the gauge into the mounting opening or it will leak. Finish tightening the water pressure gauge in place with a wrench around the brass gauge base. Tighten the new gauge carefully in position with a wrench on the gauge bottom brass fitting. Do not over-tighten, but screw in the new gauge until there is no water leakage.
• Screw in the new gauge first by hand, finishing it with a wrench around the brass gauge base. Turn pump electrical power back on. Observe new gauge pressure indications for normal operation. If you are confident that the new pressure gauge is properly installed and in good condition but water pressures are incorrect, the problem may be at the water pump pressure control itself.

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PLUMBING TOPICS
WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER PRESSURE REGULATOR ADJUST
WATER PRESSURE REPAIR GUIDE & COSTS
WATER PRESSURE LOSS DIAGNOSIS GUIDE
WATER PRESSURE & FLOW MEASUREMENT
WATER PUMPS & WELL TANKS
WATER PUMP & TANK SAFETY
WATER PUMP CONTROLS & SWITCHES
  IDENTIFY WELL PUMP TANK COMPONENTS
  MAIN WATER SHUTOFF VALVE
  WATER PUMP ELECTRICAL SWITCHES
  WATER PUMP PRESSURE CONTROL
    WATER PUMP PRESSURE CONTROL ADJUSTMENT
    WATER PUMP PRESSURE CONTROL REPAIR
    WATER PUMP PRESSURE CONTROL REPLACE
  WATER PRESSURE REGULATOR ADJUST
  WATER PUMP RELAY SWITCH
  WATER TANK AIR VOLUME CONTROLS
  TANK AIR INLET VALVE
  TANK AIR VALVE REPAIRS
  WATER TANK PRESSURE GAUGE
  WATER PRESSURE GAUGE ACCURACY
  WATER TANK DRAIN VALVE
  WATER TANK RELIEF VALVE
  CHECK VALVES
  WATER FILTERS
WATER PUMP TYPES & LIFE EXPECTANCY
WATER PUMP SHORT CYCLING
WATER PUMP & WATER TANK REPAIRS
WATER PRESSURE REPAIR GUIDE & COSTS
WATER PRESSURE LOSS DIAGNOSIS GUIDE
WATER PUMP PRESSURE CONTROL ADJUSTMENT
WATER PUMP PRESSURE CONTROL REPAIR
WATER PUMP PRIMING PROCEDURE
WATER PUMP WONT STOP RUNNING
WATER SUPPLY & DRAIN PIPING
WATER TANK TYPES: WATER, OIL, EXPANSION, ALL
WATER TANK AIR, HOW TO ADD
WATER TANK LIFE EXPECTANCY
WATER TANK PRESSURE CALCULATIONS
WATER TANK REPAIRS
WATER TANK REPLACEMENT
WATER TANK SIZE & VOLUME
WATER TANKS HOW THEY WORK
WATER SOFTENERS
WATER TESTS, CONTAMINANTS, TREATMENT
WELLS CISTERNS & SPRINGS
WINTERIZE A BUILDING
WELL, PUMP, TANK LIFE EXPECTANCY

• Thanks to readers Nancy and Eric for questioning water pump gauge inaccuracies 11/2/2009

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