"Electrostatic Air Cleaner (Trion, Inc): Dead"

 By Ron Stultz

14 January 2017

Summary: although for a specific make and model, suspect below helpful for any brand. As circuit board has few components, most likely dead because of a switch or air flow sensor. Worth a do-it-yourself (DIY) investigate before calling service.

Background:

Trion, Inc. model TRIM-T, 120 volts alternating current (VAC) electrostatic air cleaner (cleaner) installed new, 1991.

Ionized cleaning cells (2 on this model, unit) removed regularly and cleaned in dishwasher.

No damage to 2 ionized cleaning cells.

Electrostatic air cleaners are wired directly to 120VAC,  do not have dedicated circuit or breaker and are not usually tied to air conditioning (AC) or heat pump blower or fan motor.

Note: apparently normal to not install return air duct cover, vent, with capacity to hold a paper filter when electrostatic air cleaner installed. When my Trion installed, air return vent had no way to insert paper filter. I changed out vent cover to accept paper filter (Electrostatic really not all that good at collecting large hunks of lint, other). Suggest you install or have installed, return vents with paper filter capability.

Cleaners are only "on" when: (1) getting input power; (2) main control switch is in "on" position; (3) ionized cleaning cells are inserted fully and correctly; (4) cover over cleaning cells access is fully closed and switch behind door is fully depressed and (5) air flow sensor inside unit detects air flow through ionized cleaning cells.

Note that from circuit diagram below and looking at actual circuit board, switches all are handling 24VAC, is is common "control", by electrical code, voltage in such devices. Below clearly shows that safety switch closes a relay that then supplies 120VAC to main circuit board.

Problem:

When AC blower "on", began to notice that sometimes, the green (input power) and red (output power) light emitting diodes (LEDS) on the front panel of air cleaner were not lit.

As recent house cleaning had stirred up considerable dust, wanted to run AC blower with working cleaner.

Tools Needed or Potentially Needed:

Long insulated screw driver or wooden stick.

Phillips screwdriver.

Can of compressed air.

Perhaps: liquid electrical tape, wire caps.

Investigation Steps:

For discussion purposes, the electrostatic air cleaner (cleaner) is 2 separate components. The collector cell base that is connected between the return air duct and the blower unit and is mounted permanently and the second component which is the control box that sits on top of the collector base unit.

First thing to do is ensure cleaner is getting electrical power. If you know which house circuit breaker or fuse supplies power to the cleaner, check the breaker is not "tripped" or fuse blown. Note: electrical codes do not require cleaners to have a dedicated circuit so cleaner could be on any circuit associated with room it it physically located in or any other house circuit for that matter.

If you do not know which breaker\fuse supplies power to the cleaner, proceed with caution.

Physically move to the rear of the cleaner and inspect where the 120VAC line enters the control box. The input power cable should go through a clamp that has been mounted to the control box and this clamp should be down tight on the wire to ensure it can not move or rotate in the control box power entry hole. (First time I worked on cleaner, clamp was "on" cable but not tight enough to keep cable from moving inside control box and electrical connection inside control box had worked loose.

If your unit does not have a clamp on power cable and cable simply goes into hole in box, proceed with caution or forget and call service.

Turn "off" cleaner (control box on top) (Red on switch not showing).

Remove collecting coils access panel and remove collecting coils.

Examine collector cells for bent plates, broken wires and inspect electrical contacts on top of units

If collector cells damaged in any way, need to repair or otherwise replace collector cells.

Electrical contacts on top of cells need to be clean, not bent and not electrically burnt in anyway.

Reinstall collector cells. Make sure they are fully inserted into base unit. As you should know by now, collector cells can only go into the base unit one way.

With collector cell access cover off front of unit, move small switch on control unit to the "on" position and then using a stick, depress the "safety" switch visible in the rectangular hole in the control unit. Very large white push button switch. This switch, from circuit diagram, is first control unit switch and must be fully depressed for unit to function at all. Please note here that if depressing safety switch turns on unit, collector cells will have 6000+ volts direct current (VDC) on them and although not enough DC current to kill you, would hurt if you accidentally touched the cell during this safety switch check.

If stick depression of safety switch does turn on unit, then problem is with the access cover. Where the cover fits into rectangular hole in in control unit, the clip on the back of the access panel has been bent, over time, such that it is not depressing the safety switch all the way closed. Use pliers or other to bend tab far enough out to ensure it fully depressing the safety switch.

Note that one of the times I had problems with my cleaner, the access panel was the problem.

Depression of Safety Switch Does Not Turn "ON" Unit:

If when you manually depress safety switch in control unit, the unit does not turn on, you must remove cover over control box to proceed.

If you know which house circuit breaker or fuse the cleaner is tied to, throw that breaker to "off" or remove to the fuse, killing power to the cleaner.

Note here, that the breaker that controls the cleaner may also power lighting in room with cleaner so be prepared with some sort of high powered light that is powered by another house circuit. Do not proceed with only a flashlight.

If you are uncomfortable working around electrical, simply reinstall collector cell access panel and call service.

If you do not know which circuit breaker\fuse supplies power to the cleaner, from this point, assume there is 120VAC alive inside the control unit!! Be careful. Best to use only 1 hand at a time. Go slow.

To remove the cover over the top of the control unit: with power to unit dead (if possible) using a Phillips screw driver, remove the 2 screws that go through the base unit into the control box on top of the base. As shown below, these screws are vertical and just under the upper lip of the collector cell access panel hole.

With both sheet metal screws removed, can now grasp and pull the top of the control box towards you to have it slide off the top of the control box. Note here that control box unit is now simply tabbed into the back of the collector cell base unit and thus can move. Do not pull complete control box off top of collector cell base unit.

Now, look at rear of control box where electrical power comes into box. Should see black, white and a green or un-insulated cooper, ground wire from input power cable. Ground wire should be attached to metal of control box. Black and white wires should be attached to control box wires and have plastic terminal caps over them.

Carefully remove wire caps from black and white wires. Once cap is removed, input power wires should still be attached to control box wires but may not be.

At this point, use a volt meter to measure voltage between black and white input power wires. If volt meter reads 0VAC or less than 1 volt, input power is dead (either your have already tripped the applicable breaker or removed applicable fuse) or there is a problem with input power. My input power comes from terminals on an outlet located near the cleaner. If you have no power in the rear of the control box, going to have to find where the power circuit is broken. Perhaps a ground fault interrupter (GFI) outlet is feeding the cleaner???

If voltmeter shows 120VAC across black and white input power wires, find circuit breaker or fuse which kills power to these wires. Might have to experiment with breakers or uses and check volt meter readings. Carfully.

When you are sure input power to control box is dead, take black wire and connect control box wire to it with pliers or other and then screw on wire cap. Then connect while power wire to other control box wire using pliers or other and reinstall wire cap.

With wire caps in place and input power dead to cleaner, proceed.

In my case, because of how the control box was wired to house power (enough slack power cable and securely fastened to rear of control box), I could lift up the control box and remove it from collector cell base for better access to control box components.

Once again, the control box unit is tabbed into the collector cell base unit at the back and held to the front by the 2 Phillips screws you have removed.

If cleaner wiring allows, lift up front of control box in front, like shown below, pull slightly toward you and then lift control box up off the collector cell base and slowly, carefully put into a position that will allow you to see inside the control box.

If you can not remove the control box from the top of the collector cell and can not easily get in position to see inside the collector box, suggest you simply remount the control box top cover, attach control box to base unit with screws, replace access door and call service.

Below shows inside control box removed from top of collector cell base. As shown, very limited number of components on circuit board\other..

Below shows the collector cell base with top control unit removed.

To note here is: the large cut outs where the insulated collector cell electrical contacts fit as well as on the right side, the clip that is supposed to ensure a solid connection, ground, between the control box and the collector cell base. Also notice other holes in the collector cell base as these are used by the control unit.

Looking down into the front of the control box, you can see: the safety switch, the power "on\off" switch and the round, air flow sensor switch.

The air flow sensor has a tube coming out the back that fits over a fitting in the bottom of the control box. As seen from the underside of the control box, there is a hole in the control box that is open to the collector cell base below it.

Again, the cleaner is only "on" (both the input power and output power LED's lit) when: collector cells are properly and completely inserted into collector cell base; the power switch is "on", the safety switch is fully depressed and the air flow sensor detects air movement through the collector cells.

Toggle or push button switches seldom go bad, especially when only handling 24VAC, low current. However, valid to look at wire connections to both power and safety switches to ensure connector pushed fully on and not burnt or otherwise defective. In fact, visually inspect entire inside of control box for signs of electrical burning. If any component shows signs of heat or burning, just call service.

At this point, most likely cause of cleaner not operating is air flow sensor switch. Not exactly sure how this switch supposed to operate but from appearance, has opening on side and hole in control box metal to allow access to ambient or room air as well as opening in front that goes to tube that is open to air in collector cell base unit. Theory is that once air starts moving across collector cells, creates a vacuum in sensor switch that closes contacts inside. Again, only 24VAC and limited current so not much more than a magnetic reed switch.

I have not taken the air flow sensor apart to actually see internal mechansim.

In my case, when I visually examined air flow sensor, noticed right away that port coming out side of sensor that is open to hole in side of control unit metal case was clogged with ???? Did not seem right that this port, with no tube on it, should be clogged shut.

I used dental pick to loosen clog and then used a can of compressed air to blow into the side port opening. (Always danger of damaging fragile components with compressed air but worth a shot.

Then removed plastic connection tube on front of air flow sensor and pulled loose from control unit base. Tube was clear of debris but enlarged diameter where it fit over port on sensor. With tube off sensor, used can of compressed air to gently blow air over the port on the front of the sensor. Then cut a small hunk of tube off and pressed tube back onto sensor port and other end over fitting in control unit base.

At this point, if upon inspection of air flow sensor, you do not see anything visually wrong with either electrical connectors or ports on side and out the front, could be switch is bad or something else like circuit board. Suggest you proceed ahead carefully.

In my case pretty convinced clogged port on side of air flow sensor was problem and proceeded ahead.

Note: Researched replacement for air flow sensor and found one available on eBay. Sooooo....might be available if replacement required.

Since control unit off collector cell base, turned control unit upside down to inspect bottom.

In image below, can see how collector cell electrical contacts made. Spring-type electrical contact in middle of insulating material as well as large, raised, bare metal, contact on control unit bottom. Bare metal contact on base aligns with spring-like metal tab sticking out of collector cell base. Underside of collector cell base spring-like metal tab spring-type contacts both collector cell metal frames.

In my case at the rear of the control box, found the center electrical contact had experienced some 6000+VDC arcing to control box or collector cell base.  Burnt. This was caused by one end of the spring-like electrical contact in middle of insulated material coming up out of the hole and sitting on top of the insulating material.

Point here is that both electrical spring-like contacts in middle of insulating material need to have both ends of metal tucked under insulating material. Check yours!

OK, with electrical contact end tucked back under insulating material, how to repair burnt area?

As insulating material burnt completely through or hole, used small piece of packing tape to cover hole.

Then using liquid electrical tape, applied generous amount to entire burnt area.

After electrical tape dried completely, looked like below, which should be fine.

Note control box tab on very end that fits under collector cell base metal case.

With air sensor "cleaned" and rear collector cell electrical contact repaired, placed control box above collector cell base, tabed rear of control box in collector cell base and lowered control box into place.

Visually inspected entire inside of control box one more time and then took control box top and slide it into place on the control box.

The top fits tightly over the front of the box such that the metal screw clips are up inside the control box cover.

With control box cover tabbed into rear of collector cell base, reinstalled 2 Phillips screws in the front of unit.

Replaced collector cell access down.

Switched breaker controlling power to cleaner back on.

Flipped power button on cleaner to "on".

Started up AC blower and clean came fully "on".

To be sure, turned off blower and back on again several times and has worked every time.

Have noticed that cleaner LED lights remain "on" for short time after blower or air flow is turned off.

Summary:

In my case, the air flow sensor was the problem and simple cleaning "fixed" sensor.

If you have gotten to this point, hope you have successfully repaired your unit.

As I have said above, doubt it circuit board (power supply as Trion calls it) but believe these are also still available via the Internet.