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I have a Raypak RP 2100 R405 pool heater. When I turn the rocker switch on the front panel to ?on? I get nothing or no lights on the front control panel and nothing happens to the heater. I checked and there is power going from the transformer via the blue wire to the PC board but no power being distributed to anywhere else. Is it the PC board and if so how can I check to verify this is problem? The board is expensive and no one will accept a return of this item it if this isn't the problem. Could it also be the rocker switch on the front control panel? When I first turned on the heater for the season 4 weeks ago the heater started up, went on for a few seconds then shut off. It continued to cycle on and off repeatedly for a few minutes until the heater unit shut off completely and there was a red light In the ?service? section on the front control panel. When I checked the circuits in this state there was power going to the blue wire from the transformer to the PC Board as well as the yellow wire connected to a terminal located next to the blue wire on the PC board running back to the transformer. In addition, there was power to the left side of the thermal fuse but no power running through to the right side of the thermal fuse going to the gas valve. I thought it might be the thermal fuse so I tried an experiment which I now regret ? I completed the connection bypassing the fuse across the 2 wires leading to and from the thermal fuse with my screwdriver. For a few seconds the gas valve stared to operate and then cut off completely. When I checked the circuits there was no longer any power to the thermal fuse or the yellow wire leading back to the transformer. There were green lights on the ?call for heat? and ?power? sections on the front of the control panel with no response form the heater. Eventually after a few minutes a red light came on in the ?service? section. Eventually there were no lights on the service panel which is the situation described above. I thought it might be the transformer or thermal fuse so I replaced both with brand new parts which unfortunately did not correct the problem.

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  • mvincentmd Jul 10, 2010

    Yes but I need further information.



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When you turn the power ON of the unit.It will show "Water pump" in the display". If its not showing "water pump" Then  3 things has to be checked> 1)Check ON/OFF switch right side of heater. 2)Check 120/240 volts for transformer.(Time clock,Circuit breaker,Wire connections) 3)check for 24volts to PC control board.(p6 connector --- 1Yellow and 1 Blue wire). Any of the one is faulty. If "service" is displayed on display panel then:--- "SNS" Temperature sensor out of range.Replace Sensor. Inspect Thermistor wire and Connector at Terminal P1. --------------- For step by step troubleshooting.And still to get very confirmed before replacing any part.Please click on the link show below.In that link check out page number 37 for step by step troubleshooting. ------------- Thanks. Keep updated for any more query. You can rate this solution and show your appreciation.

Posted on Jul 10, 2010

  • mvincentmd Jul 10, 2010

    The official model # for my unit is a Raypak RP2100 Model # C-R405-EN. I don't have a digital display on the control panel on the front of the unit - only #4 LED lights next to "Service", "Pressure/High limit", "Call fo Heat", and "Power". I tried consulting the link for the service manual but the troubleshooting section is apparently not directed to my unit. I apologize for resubmitting my problem but the original post was incomplete. Did you see my second post above, there is power to the blue wire connected to the PC Board but no power in the yellow wire. The transformer is brand new.

  • raj somaiya
    raj somaiya Jul 10, 2010

    Yes i saw.But if the yellow wire and blue wire not showing 24 volt then its pc board problem or may be loose wire mostly yellow.
    but if everything checks OK.) ON/OFF switch.The transformer is new and the pc board shows 24 volt then its fault in main control board.
    Thanks for the query.keep updated.



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