One of my Honeywell F50F cells (FC37A1130) arcs incessantly. Everything is clean, and I can't spot a broken wire, touching plates, or anything like that. The area of arcing is very definite (I looked through the vent on the plenum with the pre-filters out); it's a 2-3 inch section along the bottom on the side away from the pre-filters.

which model XL series do you have? There is obviously something shorted or arcing on the plates of the cell. look at the plates and see if they are laying flat and the wires are all still attached across the front of the cell. A loose, sagging, broken or bad contact on the end plates will cause the bad cell lights. clean off the area where the cell makes contact inside the unit. The metal strips that run across the ends of the cell make contact with the plates inside the cell and get their power from them, dirty contacts in any part of these contacts will cause the problem. Even a bad contact from the end cap to the plates inside the cell will cause this. Try wiggling the cell around, kind of push on it on edge to get the plates to shift slightly and clean the points where the plates touch the outer strips on the sides. Check for arcing with the lights turned off,

bad connection on plates or wires that run along the front of the plates in the cell. If you hear snapping or arcing then its the plates shorting out, look for bent plates and broken wires or loose sagging wires.

I would use hot melt glue to hold everything in place. The air cleaner works by charging the air particle at the front and there is high voltage on the plates. The polarity of the plate alternates where the first plate is positive, the second is negative, the third is positive, forth is negative, etc .
With first wire in front charging the dust particle, the plate attract the charged dust particle to the plate to capture it.

The plastic insulators may have become dislodged. If the filter is fully dry, and it is arcing, look for plates that are nearly touching. and look for the distinctive black residue the arcing will leave behind.

Depending where the arcing is occurring, the cell may need to be replaced if inslutors have degraded excessively.

If hair or a dust bunny get in there, it is comparable to a bumble bee getting caught in a bug light zapper- it might take a while to clear.

Arcing (snapping) seems too frequent

1. If the electronic cell(s) are wet from washing, turn the air cleaner off for two to

three hours.

2. Check the cell(s) for broken ionizer wires or bent plates. Repair if necessary.
3. Wash cell(s) and prefilter(s) if dirty.

It's possible that the board is at fault. Triple check and make sure all the ionizing wires are in place on both cells and that the thin collector plates are not touching each other. Also, make sure the contact points are clean on both the cells and the cabinet.
The F50 is an obsolete EAC, so parts are becoming difficult to get. If the board is bad, I would recommend unplugging the unit and using a MERV 10 media filter in its place (Honeywell designed that EAC with the same cabinet as the media filter... all they did was add a power pack on top for the EAC. The media filter will slide directly in the cells place.) You will get better filtration with much less maintenance.

you need to change the power supply please contact your heating and cooling contractor for service on the unit.

It is normal to hear occasional snapping from your Electronic Air Cleaner. This occurs when larger particles are caught by the ionizer wires. Continuous snapping is not normal however, and should be investigated as outlined below: Please note that the metal electronic cells may have some sharp edges; use care when handling the cells. Wear gloves to protect your hands from being cut if needed. Remove both electronic cells. Make sure that there is no hair, dirt, sand or any debris on the bottom inside the Electronic air cleaner. If there is, remove what you can by hand. If a lot of debris is left in bottom of the Air Cleaner, you may want to use a vacuum attachment to see if you can vacuum up what you can. Do not vacuum the Pre-filter or Post filter this may damage it. Close the access door, and then turn on the Electronic Air Cleaner and the system fan. If the snapping continues with the cells removed, contact your heating and cooling contractor for service on the unit and turn off the Electronic Air Cleaner’s power. If snapping does not continue, make sure the electronic cells are clean, dry and properly installed. Inspect the electronic cells for bent collector plates, broken wires between the plates, dirt on the insulators, and damaged collector contact tabs located on the top of the cells. Make sure the pre-filters are in good condition and are in the cabinet slot farthest from the furnace (The order of the Electronic Air Cleaner Filters are from the return duct to the furnace is: Pre-Filter, electronic cell, and then Post filter, if your Electronic Air Cleaner has one). If the snapping persists and you are unable to locate any physical cause, please contact your heating and cooling contractor for service on the unit and turn off power to the Electronic Air Cleaner.

MAKE SURE THAT YOUR CELL(S) ARE CLEAN ... CLOSELY INSPECT TO SEE THAT THERE ARE NO BROKEN IONIZING WIRES (THE SMAAL STAINLESS-STEEL WIRES THAT ARE BETWEEN THE COLLECTOR PLATES). MAKE SURE POWER GOING INTO UNIT TO IS "OFF"!!! ... NOT JUST THE SWITCH ON THE UNIT. THEN TRY THE FOLLOWING: THIS AIR-CLEANER THAS A AIR-FLOW SENSOR THAT SOMETIMES GETS CLOGGED ... IT IS INSIDE THE TOP CONTROL PANEL. THERE SHOULD BE A DIAGRAM UNDER THE CONTROL BOX COVER PLATE TO ASSIST YOU LOCATING THAT SENSOR. MAKE SURE IT IS CLEAN. THE HIGH-VOLTAGE TRANSFORMER BEING BAD USEUALLY WILL SMELL LIKE BURNT WIRING. AND WILL LOOK BURNT. MAKE SURE YOU SEE NO LOSE WIRES ... SOME TIMES THE SPARK-PLUG LOOKING WIRE GOING TO THE CELL(S) CAN BURN OFF ITS CONNECTOR. YOU CAN CHECK THE DOOR SAFETY SWITCH TO MAKE SURE IT IS MAKING CONTACT WHEN HANDLE IS PROPERLY CLOSED. GOOD LUCK ... HOPE YOU HERE THAT ZAPPING SOON ... BY THE WAY ... IF YOU GET A POWER LIT ON ... GIVE THE RETURN-AIR DUCT A SLIGHT BANG ... IF IT IS WORHING IT SHOULD SNAP CRACKLE AND POP FOR A FEW SECONDS. MAKE SURE YOU SEE NOTHING (HAIR?) LYING ACROSS THE PLATES OR IOMIZING WIRES ON EACH CELL IF YOURS HAS TWO. ELECTRIC AIR CLEANERS ARE ONLY GOOD WHEN THEY ARE KEPT CLEAN ... PET HAIR IS A CONSTANT MAITENCE PROBLEM AND CELLS SHOULD BE LEANED EVERY TWO WEEKS. FOR BEST PERFOMANCE. Joe_Rex 40+ years Hvac Contractor (retired)