DIYbanter - View Single Post - Hot Surface Ignitor replaced..still won't fire up..

Tony Hwang

wrote:
Back in the spring, my 1987 Carrier Vertical GFA system wouldn't fire
up. I saw that after the HSI didn't come on, it went into shutdown
mode. I figured I'd replace the HSI before fall.

Now, $30 later, the new HSI still won't fire up. The draft induction
motor starts, but no HSI. Could this problem be in the control module?
Is there any suggestion for giving it another DYI repair before I call
in a pro? Any links? Thanks.

Hi,
You should hang a meter on the HSI connector to read 120V AC before
replacing it.(I keep a spare HSI all the time)
What is error code? If HSI does not glow it is not getting the 120V it
needs on time. Control board may have a cold solder joint due to heat.
Or relay which switches HSI power is not working. In this case it could
be relay itself or logic signal controlling it.
I have a same family furnace here and went thru logic board once so I am
quite familiar with it.
Again, what is error code?
One thing I can suggest you off my head is flip the board over and look
carefully under the two high Wattage resistors to see if the solder
joints is cracked due to heat. I mean hair line crack. Wiggle the
resistors to confirm it. If indeed tha's case, resolder the joint and
drill couple holds around the resistor on the plastic cover for good
cooling. BTW, manual has trouble-shooting flow chart.
Good luck,