Hello, I have an achiever 90 plus ruud, when I turn it on the flame ignites but after 3 seconds it goes out, it does this 3 times than turns off. Help?

Look in the blower motor conpartment the is a re set button . Red one .

This could be water in the hoses that connect to the pressure switch , they should just pull off and blow then out also blow out the pressure switch , this sound like a moisture problem with all the bad weather you h, check air filter is not blocked .

no it shouldnt have anything to do with the cover, tighten all bolts, grounds, screws that you can find. Find the flame sensor and try cleaning it and also make sure sensor in inside the flame. let me know.

Hi,

Here is a tip that will help you try to figure out why your furnace is not working.

Basic Furnace or Heating System Troubleshooting

heatman101

Hi,
It would seem as though you have a bad flame sensor or the ground from the burner to the ignition control is bad...

Could be the ignition control also but not nearly as likely...

Pressure switch can also cause these problems...

Bottom line is that you will need to grab a meter and try to figure out what is causing the flame to cutout...

Here is a tip that will help you try to figure out why your furnace is not working.

Basic Furnace or Heating System Troubleshooting

heatman101

Hi,

Here is a tip that will help you try to figure out why your furnace is not working.

Basic Furnace or Heating System Troubleshooting

heatman101

Problem: Your furnace will not ignite the gas to produce heat for your home. When a furnace has a bad ignitor what I see most of the time is the following sequence of operation:

1. Thermostat calls for heat. 2. Draft inducer motor starts. 3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes. 4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small metal probe about 1/8" in diameter, with a white porcelain base) does not sense the flame, so after 8 to 10 seconds the hissing sounds stops with no ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas. Solution: You probably need to purchase and install a new ignitor. I would suggest that you inspect your ignitor closely for cracks. Make sure you do not touch the ignitor with your bare hands. If you do not visually see a crack, then you could have a furnace control board problem or a limit, rollout switch problem. The furnace's control board might not be supplying the voltage to the ignitor. If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you need to clean your flame sensor with light sand paper or steel wool. You might need a new flame sensor, but most of the time they can be cleaned an will work well after cleaning.

It sounds like the first thing to do is have burners and pilot cleaned and adjusted so ignitor and pilot flame is close to main burner ignition rail.

The "whoosh" is due to delayed ignition because the pilot flame does not come in contact with main gas.

One more thing that should be tested is the gas pressure and combustable air mixture to be sure it is correct.

It is always best to have a qualified technician do this for you, In many areas the gas supplier with check and safety test this for you.

does the furnace ignite?? your system may not have been lighting and has gone into ignition lockout count the codes of the led lights then remove panel led diagnostic codes are listed there.
if led codes indicate no problem verify capacitor is good and that mtr is getting 115 volts.

The door, you mean the metal cover on the front? if you have the door off and push the safety switch in with your hand everything works fine? I need more info here, but if what I said is right, then the "door" isn't making good contact with the switch.