When we turn the tv on it comes on then their is a small flame sounds as though it is arching then tv shuts off takes about 2 to 5 seconds for this

It sounds like you are on the right track. Be sure you can take back the parts if they do not solve the problem. Most flame sensors to go bad over time.

Sounds like you could have 1 of 2 problems:

1. The flame sensor is dirty. The flame sensor is a small rod just a little bigger around than a pencil lead. It is located in the burner section just a few inches left or right from your glow ignitor. The flame will surround this sensor, but it the sensor is dirty, it cannot sense the heat of the flame. Take the sensor out of the furnace. It generally has one screw holding it, and one wire connected to it. Use emory cloth or light sand paper, or even a small wire brush to clean the sensor. DON'T GET IT WET.

2. You may have air in the gas line. This happens especially if the gas has been turned off to the house. You can bleed the gas line by loosening the gas line connected to the furnace. (furnace turned off) Bleed it just for 10 seconds or so, tighten the gas line, check for leaks with soapy water, and try the furnace again. You may have to do this more than once.

Hi, this sounds as though your flame sensor is dirty causing the burners to shut down with in a few seconds. The flame sensor plugs into either your circuit board, or ignition module which ever you have. It has a long rather heavy wire, most are orange in color and look like a spark plug wire that lays along side of your automatic pilot. Some are made of porcelain with a metal tip on them that is in the pilot flame. This is what needs to be cleaned. Use a fine piece of sanding cloth or better yet, steel wool. Make it shine. Now try it. If it still shuts down, something else is locking out the module. Get back to me on this, just post a comment for me and I will check in on you. Please rate me on my help to you, and thank you.
Shastalaker7
A/C, & Heating Contractor

Ok so here is a sequence of the heater lighting and the solution for your problem...
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. Please see "limits, rollout switches & furnace control boards" further down on this page. 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. Please see the pictures below to help you identify a flame sensor.
Thanks and I hope this helps. Feedback apprec.

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.

If it was arching, It could be the HV Transformer, or the High Voltage Block. It could also be that there is a High Voltage Leak at a Anode Cap on one of the CRTs. Because of the arching issue, I would call a Mitsubishi Professional to diagnose it. If you need help in locating one, call Mitsubishi at 1800-332-2119 and they could help you find one local to you.
I hope this helps,
Skyassoc

Sounds like a flame sensor problem. The board is not getting the proper signal from the flame sensor so it thinks the burner did not light and shuts the gas supply off. It keeps the blower operating to ensure that no gas is accumulated in the burner area. I suggest you contact a local mechanical contractor to service your heater.

the pilot is there for two reasons one is to light the main burners the second is the safety feature. when the pilot is on there should be a cylindrical tube of metal near the flame. that tube is either a thermalcouple or a thermalpile. the t-couple or t-pile converts the heat energy to small amounts of dc voltage. the dc voltage powers a small magnet inside the valve when the voltage gets to low the magnet will release causing a small "click" and the gas will shut off. one thing that you can do to try and fix it is make sure your pilot is encompassing the top 2 3rds of the T-couple or T-pile and that the flame is strong and not blowing around when the burners come on. the second thing is that the T-couple or T-pile may have become weak with age, the only way to test the out put is with a special inline adapter. nice thing about T-couples and T-piles is that there a fairly in-expensive part. hope that helps some. good luck

A Make and Model number of the furnace not the thermostat will help but I can walk you thru the operation of a typical furnace. It sounds to me that the burners are igniting properly but the flame sensor is not sensing the flame and shutting down the system. You will need to find the sensor and clean it and check the wire from it to the control board. Typically, the flame sensor is found at one side or the other of the burner box. It is a small probe that the flame hits. Depending upon your model it may have a small wire attached to it leading back to the control. Or it may be part of your auto-pilot assembly. ? At any rate, you will need to get to it and very delicately brush it off. Then inspect the flame channel. This is a trough area where the flame travels to ignite all burners. Over time, they tend to fill with rust and debris. Take a small screwdriver and run the blade down the trough. Inspect the wire that goes from the flame sensor to the control board. Make sure it is not frayed or broken or shorting out and that the connection at the board is good.

Beyond that, it's time for a technician to come.

Let us know the Make and Model of the furnace (found inside the furnace cabinet) and maybe we can help you further.

yes ,it sounds like screen adjustment or focus block, should be around $200- $325 to repair.