Electricity is flowing fine to the unit, gas is flowing fine, but the "hot surface ignitor" is not igniting. This is a frequent problem I've had over the years, and seems to get worse as time goes by. I've had it "repaired" a couple of times but technicians never would show me what they did. It seems like a system that is prone to frequent failing. Is there something I can do to fix it and then to maintain it so this no longer occurs, or is this new-fangled "hot surface ignitor" technology so sophisticated and complex that I'd be better off hiring a technician and/or replacing the faulty part? Thanks - Tom in L.A.
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Re: LARS 2 LITE HOT SURFACE IGNITOR IS NOT IGNITING
I think you could be buying you own HSI part and replace yourself. But I would suspect that the technicians are not being careful when the install the new ones, or someone is getting their hands on them. But even at that, they are problematic. I am not sure if there are different grades of HSI's either, so that may be the problem too. They are not that hard to replace. You just need to be sure that it is the as being the cause of the failure.
I would order new ones on the Net, and replace. Just be sure not to touch the HSI, PERIOD. Use only the wrapping that the HSI comes in to hold it, and only remove when all possibility of touching it has gone.
Let me know if you have any more questions. I'll be happy to reply. I somehwat got out of the business as HSI's were coming in, but I do know the right questions to ask, and how to figure out what's happening.
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Need to check power to your gas valve the same time the ignitor lites up. should have 24 volt. If so, replace gas valve, if not, you could have a board problem. Check for flashing codes thru the window of the blower door. Look at your label on the opposite side of the blower door and tell me what it says. (count the flashes)
Cycle the power first & see if the furnace goes through the normal sequence of order. On a call for heat, the vent inducer motor should turn on and the pressure switch should prove negative draft in the heat exchanger. the board then should power the ignition phase whenter it is hot surface ignition, or spark, you should hear a spark or see the orange glow of the ignitor & the gas valve is timed to turn on. If you have proper gas to the furnace, it should allow the gas to flow through the gas valve & ignite the flame. Once the flame is ignited, the romote or local sensor should sense the flame & the blower then kicks on from the time delay in the board. If you don't have any ignition, then something is wrong with either the ignitor, ignition module, pressure switch, or you have a manual limit that is tripped(this looks like a small 1/2 inch disc with a reset button on it) If you have ignition & the flame lights, but drops out, then your flame sensor is dirty & needs a touch of sand paper to clean it up(this looks like a 3 inch metal rod opposite of the ignitor) Make sure your power is off when you clean the sensor if you need to. Also if there is no ignition & the vent inducer motor is running... if it is hot surface igniton, there is a molex plug on the leead wires to it- disconnect & check continuity- should be under 110 ohms.
COMMON PROBLEM THE UNIT MAY HAVE A BAD HOT SURFACE IGNITOR .... these often go bad... if you have avolt meter unplug the ignitor and turn heater on see if you are getting 120 volts to ignitor plug...if so then the ignitor is bad and needs replaced....
The unit will go into lockout after a couple of attempts to start and fails. The most common reasons for this are the gas is shut off or not reaching the unit somehow, either the gas line in or the gas valve itself is defective, or you can also have an ignitor out. Depending on your model, you can have a ignitor the glows hot (hot surface), standing pilot, or spark (which you can hear sparking). Hope this helps.
Check to see if there is voltage going to the Hot Surface Ignitor when you first try to fire it up. If you have voltage but it fails to glow, the hot surface ignitor has failed and will need to be replaced.
Also ensure you have proper flow through your boiler......make sure you have water flowing through the boiler and, if there is a flow switch, check the voltage across the two terminals of the switch......check each to ground for voltage. If you have voltage, then check the voltage reading across the two terminals themselves, you should read 0 volts across the terminals (indicating the switch is closed).
Hot surface ignitors are "wear-n-tear" items and should be the first place to check.
I hope you find this information to be very helpful to you moving forward.
Please let us know if you need further help. :-)
The sequence is Igniter comes on, valve comes on, flame sensor senses flame. If no flame is sensed after 3 tries, a lockout occurs. If you have a volt meter, check for 24-27 Volts AC coming to the gas valve, if your getting voltage to the valve but no gas, your gas valve is defective. It could be a intermittent problem, no matter, still a bad valve. if no voltage to valve, defective circuit board.
Hi! First of all does this unit uses a hot surface ignitor or a spark ignitor? A hot surface ignitor is a resistive element that will get hot enough(glows yellow to near white) that ignites the main burners directly and a spark ignitor will light a pilot light first then that pilot light will ignite the main burners. If your system uses the hot surface ignitor then there will be a flame sensor on the last burner that lights. This is a thin silver metal probe that is actually in the burner flame when that burner is lit. It is held in place normally by a 1/4 inch screw. It will have 1 wire attached to the end by a female spade connector. You can pull this wire off before you remove the flame sensor to clean it. Use a fine emery cloth to lightly sand off any residue on it. Also you will need to clean the end of that burner that the flame sensor serves as this is normally the grounding field. This is most likely the problem with your system if it is a hot surface ignition type. If your system is the spark type then the problem is similar. Normally the pilot light is toughing a small flame sensing probe that is next to the pilot light. This probe also has to be clean. One more thing to look at is to see if the pilot light is large enough to surround the flame sensor. If the pilot is weak it will not touch the flame sensor enough and the system will do what it is doing for you now. If the pilot is weak then the pilot orfice is restricted. This should only be looked at and repaired by a qualified service technician. I hope I pointed you in the right direction!! Good luck!!
Check the roll out switch(s) and the lock out switches. They are a small disc looking about the size of a nickle, with with 2 wires attached on them. There will be a re-set button in the middle that resembles a small peg. Push this in to re-set. As the glow coil shorted out, the fuse on the control board may have blown. On the newer furnaces find the main board and look for a car type fuse. If blown, replace. You also have the symptoms of a bad limit switch, by the clicking noise (the heat fan relay) and the blower fan running instantlly.