TROUBLE SHOOTING PROCEDURE FOR AIR RITE MODEL 610 MODEL 610 HP AIR VOLUME CONTROLS.
- VOLTAGE TEST
- PRESSURE SWITCH
- MODEL 610HP ONLY
- ELECTRODE CIRCUIT CHECK
- CONTROLS WITH AN EXPIRED WARRANTY
- GENERAL COMMENTS
- TROUBLE SHOOTING PROCEDURE
- INSUFFICIENT AIR IN THE TANK
- INSUFFICIENT AIR IN THE TANK AND COMPRESSOR NOT RUNNING
- NO VOLTAGE AT MOTOR TERMINALS
- INSUFFICIENT AIR IN THE TANK AND COMPRESSOR RUNNING
- LEAK TEST
- COMPRESSOR PERFORMANCE
- LIQUID LEVEL SWITCH TEST
- ELECTRODE CIRCUIT TEST
- EXCESS AIR IN THE TANK
- UNUSUAL NOISES, VIBRATIONS, ETC
- REPLACEMENT OF PARTS
This procedure is a guide for locating the cause of a malfunction of an Air Rite Control installed on a hydropneumatic tank. Anyone who has experience in working on mechanical and electrical equipment will be able to perform the tests described below.
WARRANTY: It is important to be aware of the fact that the warranty on a new control may be voided if the control is tampered with, other than performing simple tests. Before starting to work on a control, determine whether the warranty is still in effect. The tests below are divided into tests for new controls and tests for controls out of warranty. Nothing in this procedure should be interpreted as a permit to waive the conditions in the warranty.
NEW CONTROLS, WARRANTY STILL VALID: These are tests which may be made on controls which fail to function at installation or shortly thereafter:
- Check voltage of supply line,
- Check pressure switch adjustment,
- Check Electrode Circuit function.
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VOLTAGE TEST: Test the voltage across the control's line terminal block: terminals with a voltmeter. This should read 105 to 127 volts for a 115 volt circuit or 204 to 250 volts for a 208 or 230 volt circuit. If voltage outside of these limits exists, get it corrected before attempting to operate the control. It is very important that the control have its own branch circuit which is connected to the main entrance switch of the pump station. The control should never share a branch line with a motor or other load.
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PRESSURE SWITCH: The control's compressor motor will not run if the control's pressure switch is open. The pressure switch on both the Model 610 and 610HP should be set to close (make contact) when the tank pressure is at, or less than, 5 PSI above the pressure at which the water pump starts. For example: if the tank pressure varies between 40 PSI and 60 PSI, the control's pressure switch should close at 45 PSI.
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The position of the contacts in the Model 610 control's pressure switch can be observed visually. After it has been established that the Model 610's pressure switch is closed when it should be and if the motor still doesn't run, proceed to the operation described in Section 3.100 below.
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MODEL 610HP ONLY: The Model 610HP pressure switch must be tested electrically to determine the position of the contacts. The easiest way to do this for the Model 610HP is to shut off the water pump and let the tank pressure descend to about 10 PSI. Then short one terminal of the thermostat to ground and turn on power to the control. If the motor starts within one minute, the pressure switch may be set too low. Next, leave the control's motor running and start the water pump; if the compressor motor stops before the tank pressure exceeds 6 PSI above the pump "START" pressure, the control's pressure switch is set too low. In this case, readjust the control's pressure switch in accordance with Air Rite Form 143. If the control's motor did not start when the tank pressure was 10 PSI, while the thermostat was shorted to ground, and the power was on, some other problem exists. In this case, send the control to the factory or authorized service center for warranty repair.
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ELECTRODE CIRCUIT CHECK: (Model 610 and MODEL 610HP) . The control's liquid level switch is connected to an electrode suspended into the tank from the control's base. When the electrode contacts water in the tank, the liquid level switch will conduct. If the control has power, and its pressure switch is closed, the control's motor will run when the liquid level switch conducts.
To test the electrode circuit, first make certain that the pressure switch is closed and that the control is receiving power. Then short the outboard terminal of the thermostat to the chassis with a jumper wire. (This is a low voltage circuit.) The motor should start within one minute of connecting the jumper. If the motor doesn't start, send the control back for warranty repair.
If the motor starts and then stops when the jumper is removed, either the electrode is not contacting water, the water doesn't ground to the tank or the electrode is not electrically connected to the liquid level switch. The next step is to move the jumper wire to the inboard terminal of the thermostat. This places the thermostat in the test circuit. If the motor now fails to start, the thermostat contacts are open. If the baffle, upon which the thermostat is mounted, is very hot, the thermostat may have opened because of its normal operation. Cool the baffle to see if the thermostat will close and cause the motor to start. If the motor now starts, the control is probably operating correctly, but if the motor doesn't start, send the control in for warranty repair.
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Should the above tests not locate the problem, either the electrode is not connecting the liquid level switch to the water in the tank or the water is not grounded to the tank. The latter is extremely unlikely. The next step is to turn off the power to the control and allow the water pump to pump up the tank. Disconnect the wire from the outboard side of the thermostat and use an ohmmeter to measure the resistance between the thermostat inboard terminal and the chassis. If this resistance exceeds 4000 ohms, the electrode circuit is not achieving proper conductivity to ground. In this case, turn off the water pump, drain the water from the tank and remove the control from the tank. Examine the electrode to see that it is intact. If the electrode is in place, measure the resistance between the electrode and the thermostat outboard terminal; this should be less than 10 ohms. If this resistance is greater than 10 ohms and the reason for the high resistance cannot be determined by examining the electrode and electrode wire, send the control back for warranty repair.
If this measurement is less than 10 ohms, the problem may be due to poor conductivity between the water and the tank. To test for this conductivity, allow the pump to fill the tank to a level where the electrode can be immersed in the water when the control is laying on its side on top of the tank. (The tank is at atmospheric pressure during this operation because the control is not attached to the tank). When the electrode is in the water, measure the resistance between the feed-thru connector in the control's base. (Where the electrode wire is attached) and the tank. If this value exceeds 4000 ohms, the water is not grounding to the tank properly. In this case, a connection must be made between the water and the tank steel shell either by installing an electrode on a pipe plug which is below water level or by installing an electrode suspended from a second flange fitting on the top of the tank. This second electrode should be connected to the control's chassis by an electric wire. This operation should insure proper functioning of the electrode circuit.
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CONTROLS WITH AN EXPIRED WARRANTY: Since controls in this classification do not have a warranty to protect and presumably, have been operating in a satisfactory manner for a year or longer, the owner has the option of performing more extensive tests to locate a malfunction. As a general rule, a control which has been performing in a satisfactory manner for a period of time, and then suddenly malfunctions, probably has a part failure. The emphasis of testing in this case is placed upon internal malfunctions, and the tests given below will probably locate the trouble.
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GENERAL COMMENTS: When a control has been operating in a satisfactory manner for a period of time and then suddenly ceases to function, the trouble is probably being caused by an internal part failure. The first steps to be taken in a case like this are to look for obvious things such as the water pump not operating, an open switch on the switch panel, etc. Test the line voltage at the control's terminal block and make certain that the control's pressure switch is closing when it should. If the water pump pressure switch setting had been raised, and no compensating adjustment had been made to the control's pressure switch, the control would be "locked-out" and could not operate.
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TROUBLE SHOOTING PROCEDURE: A malfunction of the Air Volume Control will fall into one or more of the folowing classifications:
- Insufficient air in the tank,
- Excess air in the tank,
- Unusual noises, vibration, etc.
These classifications are treated below in the order given.
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INSUFFICIENT AIR IN THE TANK: This situation can be caused by an air leak, the compressor not pumping air into the tank, or both. The first step is to determine if the compressor runs when it should.
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INSUFFICIENT AIR IN THE TANK AND COMPRESSOR NOT RUNNING: If the water level in the tank is excessively high and the compressor does not run at any time during the water pump cycle, either the compressor motor is not receiving power or the motor is defective. Check the pressure switch setting in accordance with Sections 2.120, 2.121 and 2.122 above.
Next, test the electrode circuit in accordance with Section 3.110 above. If the control's pressure switch is closed and the electrode circuit is jumpered to ground, voltage should appear at the motor line terminals. Turn off power to the control and remove the access plate from the motor terminals. Turn on power to the control and test for voltage across the motor terminals. DO NOT SHORT THE TERMINALS TO GROUND - THIS WOULD INSTANTLY RUIN THE LIQUID LEVEL SWITCH. If the proper voltage appears at the motor terminals and the motor doesn't run, the motor is defective. Have the motor repaired or replaced.
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NO VOLTAGE AT MOTOR TERMINALS: If the pressure switch is closed and the electrode circuit is jumpered to ground, voltage should appear at the motor terminals within one minute of the time voltage is applied to the control's line terminals. Failure of voltage to appear at the motor terminals means that one or more of three faults exist. (1) The pressure switch is not conducting, (2) the liquid level switch is not conducting or (3) the harness assembly is not conducting. The possibility of having a malfunctioning harness assembly is quite remote. Turn off the power and connect the two wires going to the pressure switch together on one terminal of the switch. This takes the pressure switch out of the circuit. Turn on the power. If the motor now runs, the pressure switch is probably defective and should be replaced. If the motor doesn't run, the liquid level switch is probably defective and should be replaced.
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INSUFFICIENT AIR IN THE TANK AND COMPRESSOR RUNNING: This situation would be caused by (1) the compressor not pumping, (2) an air leak or (3) both of the above.
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LEAK TEST: Inspect all fittings on the tank for air leaks. The tank should not be equipped with an air vent valve. If the tank does have a vent valve - remove it. There should be no pipes or valves connected to the tank above the water line except those required for pump control or instrumentation. If the tank is old, and there is a possibility of a weld leaking air, the entire top side of the tank should be swabbed with soap suds to see if any air leaks exist. Inspect the pneumatic system of the Air Volume Control for air leaks. Use a good grade of liquid leak detector to check all joints. Remove the tubing from the compressor and test for air leaking from this tubing by inserting a small wad of cotton in the end soaked with liquid leak detector. If air is leaking from this tubing, the check valve will have to be replaced. The tank pressure must be relieved before the check valve in the control can be removed.
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COMPRESSOR PERFORMANCE: If the leak test does not reveal an air leak, and the compressor runs when it should, it may be concluded that the compressor is not pumping air properly. Remove the compressor assembly from the control and send the compressor in for repair. The tank should be charged with air weekly until the control is restored to operating condition. A small portable air compressor may be utilized for this purpose.
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LIQUID LEVEL SWITCH TEST: Refer to the diagram on the baffle of the control, or to the electrical diagram pages, 3000.3 or 3000.4, of this procedure. (The serial number of the control must be known to select the proper electrical and pneumatic diagram.) After the motor has been tested and it has been determined that no voltage exists at the motor terminals, the liquid level switch and other electrical components should be tested. Turn off the power and test the fuses at the electrical panel. If a fuse is blown, replace it and see if the motor will run without blowing a fuse again. Sometimes fuses fail for no good reason, but this is not a frequent occurrence. The pressure switch jumper and thermostat ground jumper discussed above may be left in place for a few minutes after the fuse has been replaced, but must be removed before the control is placed back in service. After the possibility of a defective fuse has been eliminated, the liquid level switch function should be checked. The thermostat grounding jumper should be on the yellow wire which goes from the liquid level switch to the thermostat; move it if it happens to be on the feed-thru connector side of the thermostat. Turn on the power and test for voltage between the red wire on one motor terminal and the blue or purple wire on one pressure switch terminal. If voltage exists here and the motor is not running, check for a loose connection on both ends of the brown or yellow wire connecting the pressure switch to the motor. If no voltage exists here the liquid level switch is probably defective and should be replaced.
In the event that the motor does run when the pressure switch and thermostat jumpers are in place, the liquid level switch is probably in working order and the trouble lies with the pressure switch or the electrode circuit. Remove the pressure switch jumper and observe whether the motor will i-un when the pressure in the tank is not more than 5 PSI above the pressure at which the water pump starts. If the control pressure switch fails to close at the lowered tank pressure, adjust it per Section 2.120 above. Should the pressure switch still not close after being adjusted, replace it.
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ELECTRODE CIRCUIT TEST: This test should be made after the switch panel, fuses, motor, liquid level switch and pressure switch have been eliminated as possible sources of trouble. If the trouble is in the electrode circuit, the motor will definitely run when the pressure switch is closed or jumpered and the liquid level switch electrode wire is grounded. After it has been determined that the trouble is in the electrode circuit, the thermostat should be tested. Place a jumper from the terminal on the thermostat which is connected to the feed-thru connector (under the motor) and ground the other side of this jumper. Be careful not to ground the other side of the thermostat which is connected to the liquid level switch. Failure of the motor to start when the feed-thru wire is grounded indicates a faulty thermostat so the thermostat should be replaced.
(NOTE: The thermostat will automatically open when it experiences a temperature of 120 degrees Fahrenheit and it will not close again until the temperature has fallen to 100 degrees Fahrenheit so the thermostat should be cooled down to test it in case the control is exposed to the hot sun while this test is underway. Also, allowance should be made for the time delay in the liquid level switch.)
After the thermostat has been eliminated as the possible source of trouble, the rest of the electrode circuit should be tested. The next step is to determine if the electrode is making proper contact with the water in the tank. Make certain that the tank contains enough water to immerse the electrode.
Remove the liquid level switch wire from the theimostat and measure the resistance between the unconnected terminal and ground with an ohmmeter. This reading should be less than 4000 ohms. Usually it will be between 100 ohms and 1000 ohms. If the resistance is less than 4000 ohms, the liquid level switch should switch "ON" when connected to the electrode circuit, so check for a loose connection. A reading of 4000 ohms or higher indicates that either the electrode is not immersed in water or that the electrode is missing. Before proceeding further, make certain that there is sufficient water in the tank to cover the electrode, assuming that the electrode is in place and located where it should be per the installation instructions. After it has been definitely established that the electrode should be immersed in water if it is properly located in the tank and the resistance reading is still high, it will be necessary to remove the control from the tank and examine the electrode to discover what the trouble is. If it is discovered that the electrode is missing, replace it and re-install the control on the tank, taking care to get an air tight joint. The replacement of a missing electrode should solve the problem.
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EXCESS AIR IN THE TANK: When this occurs, one of two conditions exist:
- The water pump is injecting air into the tank,
- The control is injecting excess air into the tank.
If situation "1" exists, the control will seldom or never operate; if situation "2" exists, the control will run excessively.
Should the surplus air be due to the water pump, install a suitable air vent valve on the inlet pipeline to the tank. Do NOT install a vent valve on the tank. The vent valve will release the air before it can enter the tank and thus allow the control to resume its function.
Excess air caused by the control is due to an internal malfunction of the control. The first things to check are the pressure switch setting and the electrode circuit. The procedure for adjusting the pressure switch is given above. The control pressure switch should open within a few pounds pressure of the pressure at which the water pump pressure switch opens. Should the control pressure switch be set excessively high, the control will inject too much air into the tank. It should be noted, however that the control pressure switch would have to be grossly out of adjustment to cause a noticeable effect so it is unlikely that a minor mis-adjustment of this switch would cause excess air in the tank. The more likely causes of this condition are a ground in the electrode circuit, or a failure of the liquid level switch.
After eliminating the pressure switch as the possible source of the trouble, check the electrode circuit by removing the liquid level switch wire from the thermostat. If the removal of this wire stops the motor from running, check the thermostat for a ground. If it is discovered that the thermostat terminals are grounded internally, replace the thermostat. This thermostat is quite reliable, so be sure to double check before definitely deciding that the thermostat is faulty. After the thermostat has been eliminated as a possible source of the ground, the rest of the electrode circuit
must be checked. Remove the yellow feed-thru connector wire from the thermostat and measure the resistance from this wire to ground. When water is contacting the electrode in the tank this value should be less than 4000 ohms, but when the water in the tank is not contacting the electrode, the resistance to ground should be over 100,000 ohms. Should the necessary high resistance not be observed for the unimmersed condition, check the feed-thru wire for a ground. If no ground is found on the feed-thru wire, remove the control from the tank and check the electrode wire for a ground.
A faulty liquid level switch could cause the motor to run even though the liquid level switch yellow thermostat wire is disconnected and isolated from the ground. A properly operating liquid level switch will conduct when the thermostat wire is grounded and will definitely not conduct if the thermostat wire does not have a path to the ground. Should the liquid level switch not operate properly, replace it.
UNUSUAL NOISES, VIBRATIONS, ETC.: to check for unusual noises be sure to check the compressor mounts, counter balance weight and fan. Tighten any loose parts. Check the vibration bar to make sure it is bearing firmly against the tank.
Sparks or smoke indicate a short or loose connection. Check the wiring when this occurs.
If the tank has excess pressure, check the control pressure switch. This switch should open at a pressure that is not more than 5 PSI above the pressure at which the water pump pressure switch opens. In most cases, the control's pressure switch will open at a pressure that is lower than the pressure at which the water pump pressure switch opens.
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REPLACEMENT OF PARTS: Whitewater Manufacturing will supply any spare part described in the parts list. The compressor is supplied as a complete assembly only because field repair of this unit is impractical without proper training and equipment. Do not attempt to replace parts with unauthentic substitutes because this may cause malfunctioning of the control at a later date. The control Model Number and Serial Number must be given when parts are ordered to insure that the proper replacement part will be sent.