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Mystic Tan - Booth repairs Customer switch / Air pressure switch Symptoms - with booth powered, tanning level can be sent to booth and customer button lights (green), but no tan is delivered when customer button is activated. Diagnoses - the customer activation circuit consists of a series input into the PLC input port #1. In series is the customer switch along with the air pressure switch. The air pressure switch is used to prevent a tan cycle from beginning when the air supply to the booth falls below the switch setting. Switch pressure is typically 46psi. Failure of a Tan input can be caused by a failure of the customer switch, pressure switch, or a loss of continuity in the circuit itself.
Troubleshooting - - Air pressure switch. In many cases, lowering or removing, then reapplying the air supply will cause a non functioning switch to reset itself. The switch must have a minimum applied air pressure of 50psi during normal operations. At an applied pressure of greater than 46psi, the switch will close, creating zero resistance (ohms) across it's terminals. This can be checked with an ohm meter. An alternative approach is to short the switches' terminals to simulate a closed condition (Mystic Tan has supplied a jumper along with the booth). Several configurations of the switch have been used. Earlier models had a problem with the air line at the switch's air port not holding. Later models went to a switch with the 1/8"NPT port.
- Customer switch. This switch consists of two components; an indicator (light) and a set of contacts. The contacts as well as the indicator on this switch are susceptible to pollution from the tanning lotion. Failure of the contacts will prevent a customer activation from reaching the PLC. As with the air pressure switch, the contacts can be checked with an ohm meter. Activation of the customer switch will close the contacts. Momentarily shorting the terminals on the contact block can also be done to confirm contact operation. Use care to short the contactor block and not the indicator lamp. - Circuit integrity. Be wary of recent work performed on equipment. Pulling on wires or connectors can cause an open or short in the circuit. An easy way to confirm circuit integrity is to open the control box and view the PLC input #1 while performing a wide jump. The input indicator will light when the jump exists. If a level has been sent, the tanning cycle should proceed upon such a jump. Repair - - The air pressure switch itself is a non repairable item and must be replaced. The switch may be shorted to continue operation, but the feature of the switch is obviously removed. Because booth operation can be continued in case of switch failure, replacement units can be purchased as required. - The customer switch can be replaced as a whole unit or in sections, depending on the requirement. For polluted contacts, only the contact block requires replacement. Switch removal is required to access the contact block. Although the contact blocks can be opened and cleaned, this is impractical. As such a spare contact block should always be on hand. The rinse bushbutton and the customer switch generally use the same contact block. You should check however as two models have been used, a Telemecanique and an IDEC.
Telemecanique (left) and IDEC (right) contact blocks The Innovation style booths continue to utilize an air pressure switch. The pushbuttons have been replaced with proximity sensors which should not be affected by the lotion.
© 2004 SunlessSystems
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