Ruud furnace issue on upgrade board and flame sensor

rubberman · 10-17-2009, 11:29 PM

let me start by off by saying i have a Ruud Silhouette natural gas furnace. model UGLG-07eauer. made in 1994. In june 2009 i had the circuit board(Protech 62-24084-82) and blower motor replaced. The problem i have is that the electric glow igniter lights up and ignites the gases. The gases will stay lit for 5 secs or so then shut off. So after reading i get the picture that it would be the flame sensor. I cleaned it with steel wool but it made no difference. so i thought maybe i need a new one but no one is open on the weekend. But after doing more researching it shows that the updated circuit board might need the remote flame sensor kit. But since mine already has a flame sensor, the wire needs to be re-route from the white wire.

Quote:

If there is no flame sensor then you will need to install one, run the supplied wires per the instructions to the new 3 light control board. ( 2 Green & 1 Amber Light)
If there is an existing flame sensor, check the wiring, if it is spliced into one of the Hot surface Ignitor wires it will need to be disconnected and then run the supplied wires per the instructions to the new 3 light control board. ( 2 Green & 1 Amber Light)

Flame sensors Installed with 2 Light Boards was spliced into the Ignitor wires.
Flame sensors Installed with 3 Light Boards must wire back to the control board.
ALL Rheem HOT Surface Ignition Furnaces should be equipped with a Remote Flame sensor.

has anyone done this? instead of buying the remote flame sensor kit since i already have the sensor. i should be able to reroute the wire to the board connector. any guidance is appreciated.

yuri · 10-18-2009, 09:33 AM

You don't need to change anything as it already has been done and has worked. Clean the face of the burner the sensor sits in front of with fine emory paper or clean steel wool. Make sure the circuit board is secured properly as it needs to be grounded properly or it won't sense the flame. The new board should have a diagnostic set of LEDs. You may have to remove the lower door and put duct tape on the door switch temporarily. Then fire it up and see if a code appears. You would need the instruction sheet with the board for the code. Post it here and someone may know it or find it on the net yourself. Check the porcelain of the flame sensor for cracks. If cracked or brown/black in color replace it.

rubberman · 10-18-2009, 10:12 AM

well i wired that flame sensor to the spot on the board as the instructions said and it works now. The flame led light comes on now which it never did before.

yuri · 10-18-2009, 10:21 AM

Good for U.

rubberman · 10-18-2009, 02:46 PM

instead of buying the RHeem/Ruud remote flame sensor kit that includes the wire, connectos and that. i think i might go to radio shack and get the same stuff. be cheaper and work the same.

yuri · 10-18-2009, 03:30 PM

Post a pic of the burner area of your furnace. Sounds confusing what you are saying. The older Rheems and Colemans used the HSI hot surface igniter as the flame sensor also. Had an extra white wire spliced into the HSI wire. The system was crap. Then they went to the standard flame sensor like everyone uses. The "remote" kit was nothing more than a flames sensor and a bracket. I think you have that already and don't need it. It is INCREDIBLY important that the flame sensor be mounted exactly where they intend it with the proper kit or you could blow up your house. The flame failure response time is less than 1 second and if you have the sensor in the wrong spot KABOOM and I am deadly serious.

This is nothing to fool around with if you don't understand it. You could be liable if someone gets hurt.

rubberman · 10-18-2009, 08:10 PM

ok here it is. the glow igniter is on the right. the red wire behind the black gas pipe is where the flame sensor is and its mount in its bracket. in the top left corner you see the 2 white wires plus the red flame sensor wire come together in that pigtail connector. the instriuctions say to remove the red wire from that pigtail and run that to the board cause this new board monitors that different than the old revision board.

yuri · 10-18-2009, 08:34 PM

Now I feel better. Just follow their instructions and you should be okay and use their parts.

rubberman · 10-18-2009, 09:16 PM

Here is another view showing the flame sensor mount.

yuri · 10-18-2009, 09:25 PM

Looks good to me and the same as their newer furnaces. You should remove the burner on the far left and clean its face with fine emory. A flame sensor is not a sensor. It is a live probe with AC voltage which jumps thru the fire and converts to DC (rectifies). Then feeds thru the burner back to the board in microamps. A dirty burner prevents current flow.

needy · 11-18-2009, 03:01 PM

Hey Rubberman, I need to install the same board. However there are two teminals missing from the new board. Any way you could post a pic of the control board. Unemployed right now and a tech wants $450 to replace the board . I can buy one for less than 200. However there are 2 extra wires and I don't know were they would go.

On the old board they are labled 24vac and com , grouped together.

Anyone else know or have the instructions for installing this board. Would like to see before ordering it, and its getting very cold in here.

Marty S. · 11-18-2009, 06:16 PM

Easy to follow instructions come with the new board needy. If I remember correctly those go through a 9 pin connector instead of directly to the board. Everything you need comes in the box,just follow the instructions.

StationaryDave · 11-24-2009, 02:19 PM

I have similar equipment and similar issues as those discussed in this thread. I went ahead and replaced the circuit board but the flame still doesn't stay on. The two green leds stay lit, but yellow flame LED doesn't come on.

I took the flame sensor out and cleaned it with steel wool and also took its burner out and cleaned it with emory cloth. I've verified that the sensor has a good ground connection to the chassis and the wires to the board seem to be in order.
Still no flame LED and gas cuts off.

Is there a way to bench test the flame sensor?

Thanks,
Dave

Marty S. · 11-24-2009, 08:08 PM

If your meter can read microamps hook one lead to the sensor and the other to the sensor wire. Reading should be over 1.8 microamps when the flame is on the rod. If less then that and the sensor is clean then replace it.

StationaryDave · 12-02-2009, 07:36 PM

Threw on a new flame sensor...same results.
The troubleshooting chart on the panel says to check these things:
- check polarity of hvac supply
- check continuity of sensor wire (checked that - it's ok)
- check insulation on ignitor leads (it's igniting fine - so why worry with this?)
- if checks are ok, replace ifc (already done that--what are the chances this one's bad, too?)

So I'm off to research exactly how to check the polarity. Why would that make a difference?