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Ask Comfort Specialist Your Own Question

Comfort Specialist
Comfort Specialist, Designer, Estimator & Technician
Category: HVAC
Satisfied Customers: 1216
Experience:  Master HVAC & Gas, Air Balance, LG Master Commissioner, University of North Carolina Certificate holder for Industrial Ventilation Design.
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four flashes on goodman c h&a and no fan so replaced limiter still 4 f

Customer Question

four flashes on goodman c h&a and no fan so replaced limiter still 4 flashes and no fan
Submitted: 1 year ago.
Category: HVAC
Expert:  Comfort Specialist replied 1 year ago.

Wvfan79 :

Hello there! I'm Norman but you can call me Norm. Let's see what I can do to get you some answers today. I'm ready to get started whenever you are.

Wvfan79 :

Hope you are doing well today.

Wvfan79 :

To start out 4 flashes on the Goodman GMH8 could be one of about 4-5 items.

Wvfan79 :

1st you could have a problem with the priXXXXX XXXXXmit switch which is up on the vestibule (back) furnace panel near the burners. 2nd it could be the Aux Limit which is mounted down on the blower cabinet, 3rd it could be a wiring issue, 4th it could be clogged filters or a blockage in the duct work and 5th a bad blower in general.

Wvfan79 :

However, you say the blower is not working at all so that eliminates a couple items. If the PriXXXXX XXXXXmit had tripped you'd expect to catch the blower running non-stop trying to move air and auto-reset itself as it cools down.

Wvfan79 :

If the blower isn't running at all then the aux limit isn't likely the cause either because it is also an auto-reset limit. However you can test them both by jumping them out with a short wire, ohm testing them, or unplugging them both and jumping the two wires together. If the furnace cycles and fires you'd know the limit was the problem. If you would like to test them I can help guide you.

Wvfan79 :

As for the blower possibly being bad... I'd like to know if it ever starts in either heat/cool/auto mode?

Wvfan79 :

Also have you already inspected the wiring for loose/broken wires?

Wvfan79 :

We can use a volt-meter if you have one to test power at the ignition board blower terminals and quickly see if there is even power getting to the blower. If you have power at the terminals and still no blower that will quickly eliminate the limits and duct, etc.

JACUSTOMER-yl2xz6ub- :

i replaced the 2 limiters you spoke of fan motor is less than a year old capisator is original fan wont come on at all can the thermostat be stoping the fan

Wvfan79 :

It's possible but we should be seeing a fault flash like this.

Wvfan79 :

Do you have a volt meter handy?

Wvfan79 :

for measuring electrical voltage

Wvfan79 :

we shouldn't be seeing the fault flash like we have... typo above.

Wvfan79 :

shouldn't be... sorry

Wvfan79 :

If you have one I'd like you to grab it and set the thermostat to Cool and Auto

Wvfan79 :

Go to the furnace and remove the two doors.

Wvfan79 :

ON the board you should find 5 wires going to the blower from the board... Black, Blue, Red, Orange, White.

Wvfan79 :

White does to neutral so place one probe where it connects to the board, then place the other probe on the board terminal labeled COOL. While each probe is touching the terminals press in and hold the door switch so the furnace has power. At this point you should read Voltage in volts AC. Let me know if you are not able to complete this step or need help along the way.

JACUSTOMER-yl2xz6ub- :

go on

Wvfan79 :

Make sure power is on, and the thermostat is set to COOL and AUTO

Wvfan79 :

Of course be cautious not to bump anything in the cabinet. Safety first!

Wvfan79 :

If at any point you feel uncomfortable proceeding just let me know and we can pause or consider other options.

Wvfan79 :

From what you've said my suspicions immediately go to the old original capacitor but we'll see where we get with these test.

JACUSTOMER-yl2xz6ub- :

so if there is volts there maybe capacitor ?

Wvfan79 :

Absolutely possible. If you have voltage my first thing would be to search and make sure all wires are good and intact. Second I'd pull the capacitor and either replace it or take it to a local hvac service parts house to be tested. A fan capacitor is like a 5-10 dollar item and easy to change. Because you always want to change the capacitor when you change a fan I'm surprised to see the original one still in there.

JACUSTOMER-yl2xz6ub- :

so what if there is no volts check volts to board and check all wires what else ?

Wvfan79 :

If no volts we would work the other direction. We'd first check to make sure there is 24v from R to C, then 24v from G to C, if you have 24 in both places we know the thermostat is getting proper voltage and calling for the fan to run. At that point it would be left at the limits and or the board itself. But with 2 new limits I'd be left to say the board would be the culprit.

Wvfan79 :

when I say R to C I mean one probe on R and one on C at the same time.

Wvfan79 :

Some times when a capacitor fails you can see a slight bulging of the top cap around the terminals. It's harder to see on a fan capacitor because of it's shape and size.

Wvfan79 :

Full Size Image
Check out this image, it's a good example of a dual run capacitor as it failed.

Wvfan79 :

A new fan capacitor should look like this with no bulging or leakage

Full Size Image

Wvfan79 :

Have you been able to make any progress?

JACUSTOMER-yl2xz6ub- :

i will take heaters and check it out and contact you when im back

Wvfan79 :

Sounds good. I'll be online all night. Please keep me in the loop.

Wvfan79 :

It may take me some time to jump back in after you get back and reply so please be patient. I'm hoping I'm sitting at the computer when you reply. Thanks for working with me today and I look forward to hearing back.

JACUSTOMER-yl2xz6ub- :

no power from motherboard to fan

Wvfan79 :

Ah. Now we are getting some where.

Wvfan79 :

Let me pull your schematics so I can advise you on the next step.

Wvfan79 :

Did you measure voltage with the door switch held in?

Wvfan79 :

Also, go to the high limit in the furnace panel near the burners and jump the high limit out from wire to wire.

Full Size Image
You will only be able to see the back plate with the two wire terminals. The wires that lead to it are red.

Wvfan79 :

I'll be standing by when you get a chance to log on and reply.

JACUSTOMER-yl2xz6ub- :

I did not see the hi limit I see a limiter by the burners that i replaced it looked like the fan limiter (by blower)

JACUSTOMER-yl2xz6ub- :

I replaced 2 limiters one down by blower and one by burners but could not see one that was like your picture is there a third ?

JACUSTOMER-yl2xz6ub- :

hay man i think i want my

Customer :

so what else can i do there is no internal limiter that i could find

Customer :

I have not been able to contact you since the night i signed up so i will need a refund please or send me a tech that can be online long enough for me to get an answer

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