RAUJ - Reset Relay Troubleshooting (R410A)

• Relay 1 (Step 1 5U11) closes.
• After 5 minutes, 115 Volts will energize both 1DL8 & 1K15.
  

• 1K15 closes
• Once 1DL8 times out, the N/O 1DL8 closes
• If all safety CKTs are close, the 1K11 can not energize because 1k1 is Energize. 1K11 does not have a Path to Common.

• After 10 minutes, 1U5 (Low Pressure Bypass Timer) will open its contacts and allow Current to Flow through the 453 (Low Pressure Switch)
  

  

• Safety CKT opens (AUX-1)
  

• Safety CKT opens (AUX-1)
• 1K1 de-energize, allowing a path to common for the 1K11 (Reset Relay)
• 1K1 (Reset Relay) energizes, closing N/O 1K11 contacts, locking 120 volts in a the Reset Relay Coil
• 1K11 N/C contact opens
• Unit requires a manual reset.
  

If you are having intermittent Trips and can not fine out why the CKT is tripping

• Install 1/16 amp fuse parallel to safeties.
• If the safety opens, the current will flow through the fuse and blow.
• This will tell you which switch is tripping. 
  

1. AUX-1 tripped.
2. 1/16 amp fuse opens.
3. Reset Relay is now energize, locking out the CKT.
4. 1K11 N/C contact opens.
5. 1K11 N/O contact opens, locking in the Reset Relay.
   

The reset relay is designed to energize upon a trip of any of the safeties/components within the circuit. The relay coil is in parallel with the safeties and in series with the contactor coil. Due to its high impedance value the relay energizes when a safety trips. The 1DL8 (or 1DL9 on two circuit units) is a 0.3-second time delay in series with the cooling relay contacts. The purpose of this relay is to prevent a condition known as "relay race" from occurring.

The below table indicates specifications of the safeties within the reset relay circuit.

Reset Relay Circuit Components

To properly define the cause of nuisance lockouts, the following steps should be taken.

1. Fuses should be installed across the contacts of the various controls in the reset circuit. To do this, an automotive in-line fuse holder assembly should be connected. Use 1/16A fuses. When one of the contacts in the reset circuit opens, the fuse will be required to carry the load of the devices downstream of the reset circuit. This will cause the fuse to blow. This allows visual confirmation and accurate data as to the device causing nuisance lockouts.
   
   R410A - Tube and Fin Coil
   Note: R410A units utilize a discharge line thermostat instead of a compressor winding thermostat.  80 - 120T units have utilize compressor protection modules.  See Microchannel coil schematic to reference wiring.  
   
   
   R410A - Microchannel Coil
   Note: 20 - 60T RAUJ units do not have Compressor Protection Modules
   

   Note: Troubleshooting may require using more fuses than are shown.
    

2. If a "relay race" situation is suspected, try replacing the 1DL8 (or 1DL9 on two circuit units) with a known good time delay.
3. If momentary power interruptions are suspected to be causing nuisance lockouts, a special control voltage signal relay or a phase monitor may be required.