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zenbones · Oct 20, 2008, 10:01 AM

Blinks three times

My goodman furnace does not ignite the HSI, and the board blinks three times. Is this the pressure switch or rollover, or perhaps something else

zenbones · Oct 20, 2008, 10:06 AM

My furnace is a Goodman GMP 100-3

hvac1000 · Oct 20, 2008, 10:51 AM

3 blinks is end switch closed without inducer on.

Check venter end switch.

Also see the back of the blower for a wiring diagram with the blink codes listed.

zenbones · Oct 20, 2008, 11:11 AM

I changed the pressure switch, and still got the three blinks. So I disconnected the tube and sucked on it to close the pressure switch, causing it to ignite the HSI. The inducer is running but apparently not creating a vacuum to the pressure switch. Could this be clogged? Do I need to take off the inducer and clean that port?

hvac1000 · Oct 20, 2008, 11:36 AM

Could this be clogged? Yes but you might check the connecting tube for cracks first.

zenbones · Oct 20, 2008, 02:43 PM

As it turns out, the inducer on the unit itself was not working. There was a secondary inducer that was causing it primary inducer to spin, but it was not coming on. I have changed the primary inducer, and now cannot get the primary inducer to work. What is the line voltage on the primary inducer. I am reading around 5vac between the white and black lines. What should it be.

hvac1000 · Oct 20, 2008, 03:12 PM

If I am not mistaken the inducer runs on 120 volts. How about posting a correct model number so we can check.

zenbones · Oct 20, 2008, 03:18 PM

The model number is GMP 100-3, and it is about 10 years old

hvac1000 · Oct 20, 2008, 04:46 PM

120 volts is the answer I found

zenbones · Oct 20, 2008, 04:57 PM

When I pull the wires off the vent motor mounted on the furnace, I measure about 5vac between the black and white wires. So would the problem be in the circuit board? According to the schematic, I should read 120vac. In the schematic, there is also a power vent relay. Is that on the board?

hvac1000 · Oct 20, 2008, 07:11 PM

In the schematic, there is also a power vent relay. Is that on the board?

Yes and it is possible it is defective.

zenbones · Oct 21, 2008, 06:34 AM

If that is on the board, and defective, does that mean I have to replace the whole board?

hvac1000 · Oct 21, 2008, 09:38 AM

If that is on the board, and defective, does that mean I have to replace the whole board?

Usually that is the solution since the relay is usually soldered to the board and not easily found at radio shack.

zenbones · Oct 22, 2008, 02:51 PM

Usually that is the solution since the relay is usually soldered to the board and not easily found at radio shack.[/QUOTE]

Replaced the whole board, and now enjoying heat once again. Thanks for all your help, you have been great.