I have a Rheem RGDE-10EQAGS 100,000btu furnace 22 years old. When it receives the heat signal from the thermostat, the White Rodgers 50E47-843 HSI control flashes yellow for the self test then steady green, purge cycle for 40 seconds, ignition HSI glows bright, gas valve opens, burners light, and it runs for about 2 minutes, then closes the gas valve, no fault codes display; immediately yellow light flashes for self test, and cycle repeats, but burners only light for about 45 seconds on the second attempt, cycle repeats with burners lit for 35-40 seconds, then gas valve closes. I jumped the High Temp Limit in the center and the flame rollout limit switches - no help. Pressure switch seems to be operating properly. I replace the HSI hoping that the cause may be a weak flame signal - no help. I replaced the White Rodgers control at the advice of an HVAC repairman - no help. Filters are clean. Blower and inducer fan run properly. I have run out of ideas.
I did not see that your indoor fan motor started. Near your indoor fan motor there is a temperature switch that is called the fan delay relay. On a temperature rise the relay shuts a contact that turns on the indoor fan motor. If the contact does not close the high temperature limit will shut the gas controls off like your getting. A fan delay relay also allows the fan to run a minute or so to carry away the remaining heat in the furnace and help cool the furnace down. The fan delay relay is normally mounted in a recessed area in the fire wall of the furnace plate. I have also seen them on the top of the furnace heat exchanger. Anyway, the fan delay relay will probably not be available on a sunday, so temporarily until parts are available, try turning the thermostat fan from auto to on and try the furnace again. By turning on the fan to on the high temp limit will not shut you down again.
I have had high temp limit change there trip points, but you said you bypassed it and did the same thing.
Another cause could be using the wrong type of air filter. The new pleated filters sold block to much air flow. If air mass flow rate drops the difference in temperatur go up and when the difference in temperature go up, it gets nearer the high limit and causes it to trip. All pleated filters drop normal air flow through ducts by at least 35%. To make your air duct system work properly use the what is called throw away filters which cost about 1/3 the cost of the pleated filter. Remember to either clean or change the throw away filter monthly to reduce dirt being drawn into your duct system.
Hope this helps.
Testimonial: "Indoor fan motor had started. I tried it with the thermostat selected to Fan- ON and it still did the same thing. So I finally just had a new furnace 95% installed this week since the old one was already 22 yrs old."
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