KNOWLEDGEBASE

1. The ErrP (PF, E- P, E-P in some older models) comes from a reset of the processor during a firing. Things that can cause a reset are power loss, a shorted relay coil, or electrical noise on the microprocessor circuit.
2. The shorted relay coil is easy. Every time the controller tries to turn on the relay, the display will go blank.
3. A pilot relay setup (such as in a DaVinci or Easy-Load panel) is usually the only time we encounter a noise issue. The cure involves a MOV across the contacts of the pilot relay, which we do as standard. Moving wires away from the back of the controller and ensuring that the low-voltage wires and TC wires are not intertwined with the power wires is also essential. For more information on electrical noise, please see this link.
4. The power loss is a little trickier since it is usually intermittent. It could be a faulty circuit breaker, a loose connection, a defective fuse holder, or a transformer issue - anything that interrupts power to the control. For instance, a transformer with a broken wire at one of its terminals could cause this, as it makes contact most of the time, but heat or vibration would open the connection. In 99% of cases, the issue is a faulty circuit breaker, which requires replacement. 
5. What do you do if this happens while you are firing?
6. Try running a new program and just see if the control works. Seeing a PF could mean that you experienced a power failure, but all is now okay.

Things to Check

1. Check Power Cord
2. Check Power Relay
3. Check the transformer for proper operation
4. Check Wires and Wire Connections
5. Check Your Voltage
6. Run a Paper Test
7. Troubleshoot an INF infinite input switch (older Manual Kilns)