Hello everyone, I have a 2010 Haier gas furnace that is short cycling. I cleaned the flame sensor, replaced the control board, and put in a new gas valve. It still short cycles. It is a White-Rodgers board. Flame rectification seems to be the issue. I checked the outlet the unit is connected to and I have 120V from hot to ground, 120V from hot to common and 0V from common to ground. I am getting a single flash code when the unit locks out. The indication is low gas pressure, bad HSI, or bad earth ground. I ran jumper wire directly from the ground on the outlet to the unit and no change. The flame sensor has about 57V going through it. I disassembled the flame tubes and cleaned the heads. Anybody out there know about flame rectification?

 

Welcome to the forums.

Please explain short cycling in more detail.
What is short cycling ?

 

Short cycling is when the unit lights for 3-5 seconds, and shuts off repeating this process until it locks out for an hour or so.

 

You need to check the flame signal. This is done via measuring mA.

 

Thanks for the reply. I checked the flame signal and the required mA was correct. Volts going in are 57V and when I check the mA the number was within range. The code flashes one time which references low gas pressure, bad HSI, or bad earth ground. I installed a new gas valve and it did not correct the issue. The HSI glows and ignites the flame. It doesn't have a hot spot on it. I grounded the unit directly to the ground wire in the outlet and no change. I also ran an extension cored from the neighboring property and no change.

 

The AC voltage to the rod is not important.
The ground from the building to the furnace isn't critical for operation..... just safety.

The ground between the burners and the control box is what is critical. Make sure the burner screws are shiny and tight. Make sure the control box is well grounded to the metal frame.

You'll need to put a meter inline with the flame rod.
You need to be able to read ua. (microamps)..... not ma. ( milliamps.)
You should see approx 2-10 ua. when the flame is started.

 

Thanks for the reply. The unit doesn't have a ground from the control box to the burner. I am guessing it grounds through the frame. I did connect a ground wire to the frame from the ground coming into the unit from the outlet. It didn't change the issue. When I checked the flame rod, I did use the DC uA on the multimeter. It gives a reading of 6.5 uA which is within range. I am sure it is something simple I am overlooking.
I also took the burners out and cleaned the flame tubes. All screws were tight when I disassembled and put it back together. They weren't very dirty. I am in Arizona so we have a very dry climate with little condensation. The unit is in a closet by itself not in a laundry room.

 

Bingo...... and that's where you could have a problem.
Your furnace doesn't require a ground from the house to work.

How do you know it's within Haier's required current range?
It's typically in the manual but since you didn't post any technical info or model I didn't look it up.

Does that number stay that way the entire time the burner is lit ?
Is the rod well engulfed in the flame. Sometimes the bracket needs to be bent. The higher you can get the current the more stable it will be. Typically 6.5uA is enough to sustain a flame but some boards require more.

There are many videos on you tube discussing flame rectification but just a quickie. The control box applies an AC voltage to the flame rod. When the burner lights.... the flame creates a bridge between the flame rod and the steel burner. That bridge is DC and is the current you measured. Then that current flows thru the frame ground back to the control box. Usually if it's a ground problem that measured current will fluctuate or be very low.

 

The manual and the error code say the unit requires proper earth ground, bad HSI, or low The ground comes through the outlet which ties back to the main electric panel.
I do not know that 6.5uA is within the manufacturer requirements. Base on my research from online tutorials it appears to be what it needs. The board is a White Rodgers board. The manual doesn't specifically say what the flame sensor needs.
It appears the unit is not getting the DC current back to the control board. Unfortunately the flame does not stay lit longer than 2-5 seconds. But the reading is stable during the time when it is lit.

 

If the reading is stable then the circuit is working.
Try this..... check from the white/neutral to the metal frame for AC voltage. There should be 0v.
What's the part number on the W/R controller ?

 

Good morning, I checked the power supply. Hot to common = 120V, Hot to ground = 120V, Neutral to ground = 0V. Neutral to frame = 0V.

The original controller is a White Rodgers 50A55-250. It was replaced by a White Rodgers 50A55-843. It was a direct plug and play that didn't need any jumper wires.

 

It shows as an approved replacement.

The only thing I can offer that may be of some help is the W/R diagnostic manual.