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Rick
Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 20757
Experience:  40+ yrs. experience as a licensed oil & gas technician.
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I have a Ruud High Achiever Super Quiet 80 model

Customer Question

I have a Ruud High Achiever Super Quiet 80 model #UPGQ-10EAMER, the fan continually runs and blowing cold air. The lights on the furnace show far right steady green, middle green flashes a pattern of 3 times and then pauses and flashes again 3 times, the ***** *****ght is not on. I have reset the furnace by shutting it off and when I power back up, the furnace fan begins running again. The thermostat fan is in to "Auto" position. When I do turn the furnace back on, I never hear the automatic pilot attempt to ignite.
Submitted: 3 months ago.
Category: HVAC
Expert:  Rick replied 3 months ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

You can try resetting the rollout switch(es) (see attached pic for typical). They are located just outside the burner chamber. Turn off the power then press the small button between the 2 leads to reset it. If it clicks you have reset it and the unit will fire up when you turn the power back on with any luck. If it doesn't click it wasn't tripped.
Check to be sure there isn't more than one by tracing the leads connected to the switch.

Customer: replied 3 months ago.
There are 2 of them, neither one of them clicked. When I turned the furnace back on, the fan immediately turned on and the pilot never attempted to light that I could tell.
Expert:  Rick replied 3 months ago.

Next trace out the leads connected to the rollouts to the limit (see attached for typical). It should be above the burners on the face of the unit. Once you find it connect the 2 leads together and turn the power back on. What happens?

Customer: replied 3 months ago.
when you say connect the 2 wires, do you mean to unplug them and touch them together or just use a screw driver to "jump" them while still attached?
Expert:  Rick replied 3 months ago.

Whatever you have to do to be sure you have and keep a good contact.

Customer: replied 3 months ago.
ok, took them off and connected them together with a piece of metal, turned it back on and again just the fan ran.
Expert:  Rick replied 3 months ago.

Then the next step is to trace those leads back to the board and test for continuity across the leads at the board. If you have continuity then the board is suspect. If you have an open circuit then you have to trace out the entire circuit and check for bad connections or open devices in the circuit.

Customer: replied 3 months ago.
I am not sure how to test for continuity. Does the middle light blinking 3 times repeatedly give us any direction?
Expert:  Rick replied 3 months ago.

That's an open limit circuit error which is what we've been tracking down. If you can't do a continuity test then you've done all you can and you'll have to call in a pro.

Customer: replied 3 months ago.
I guess we are done here. : (
Expert:  Rick replied 3 months ago.

I can't go any further with you without the continuity testing

Customer: replied 3 months ago.
with some digging on the internet, I was able to use a 3 amp fuse and by-pass the limiter system just long enough to see that the blinking green light stayed on and did not blink. The pilot ignited and I had heat. Then, one by one, I used the fuse to jumper each limiter switch independently to find the one causing the problem. What I found out was that the 3rd limiter switch was the issue. I will replace all 3 limiter switches tomorrow after work.
Expert:  Rick replied 3 months ago.

Sounds like you found a way to test the continuity of the limit circuit. Glad you worked it out.