90+ gas furnace problems

[jibroni69]

I have never seen a variable voltage ignitor? If you decrease the voltage and the resistance of the HSI remains the same, the amperage would increase. There would be no savings in that. Who uses these? every residential brand of gas furnace I know of uses a straight up 120 v HSI, not sure about those stupid honeywell smart valves though. Enlighten me plz, i appreciate it

[stvc]

I have never seen a variable voltage ignitor? If you decrease the voltage and the resistance of the HSI remains the same, the amperage would increase. There would be no savings in that. Who uses these? every residential brand of gas furnace I know of uses a straight up 120 v HSI, not sure about those stupid honeywell smart valves though. Enlighten me plz, i appreciate it

I think you might be responding to my post but am not really sure.
My question to skippedover about the incoming electrical service, phase and the operating voltage of the equipment had more to do with what the source of that problem really was, rather than the equipment itself. Electronic equipment does strange things to the sine wave and can't be measured without a true RMS meter. In a perfect world if you have a single or 3 phase system with a balanced load on all phases neutral current will be 0. When you add a buch of electronic loads to the system the power supplies in them clip the sine waves and balance becomes distorted. It does strange things. A non true RMS meter may read zero on a neutral conductor but a true RMS meter could read 500 Amps. That is why neutral conductors of multi wire systems burn up in commercial sytems. I think it may also be migrating to residential systems along with other problems.

[ZZZRSC]

I think jibroni was refering to TinKnocker's statement "with these new ignitors the voltage to them drops to the point where they wont lite to burners then on the next try the voltage is increased to the last recorded voltage the burners lit and remain there till the power is disconnected the starts the search orver again"
I have never heard of this response, but there are a lot things I haven't heard of. Also, if you reduce the voltage to an electric heater (ignitor) the amperage and wattage will decrease I=V/R and W=VxI where R is a fixed value for the ignitor. This is not true for an electric motor.

[Airmechanical]

Strange, sounds more like the time delay built into the board is malfunctioning, check the HSI for voltage and exactly when the 120v is dropped from the HSI. I suspect the board is dropping the HSI too quickly, it cools a bit and the gas valve opens. These are 18 second HSI's are they not? Double check the sequence of operations on this particular model and time when the gas valve cuts in, also check the voltage at the gas valve, weak voltage could account for valve opening late. Could be a number of things , but resistance means nothing on this one.

agreed;

that is right where i would of started, (unplug the ignitor check voltage and timing voltage was applied and disengaged)

also as others have stated, it is easy enough to change every part in the unit

but why not just use your meter to diagnose the part you are thinking of changing

in this trade (servicework) when performed properly, parts are checked then if proven faulty (with a meter) parts are changed!



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[hvactech1jm]

The gas valve does not care whether the HSI worked or not. There is no check by the board to test the HSI while it is operating.

The gas valve doesn't care, but I know of at least one control board that does. It was on a commercial boiler though. A "senior tech" with any knowledge at all wouldn't put in a third gas valve, as the likelyhood of the first two being bad is pretty slim. If there is a drain pressure switch, it has to be closed at this point to allow board voltage to the gas valve, otherwise replace the integrated furnace control board. You should have a voltmeter on the gas valve terminals and a pressure gauge on the test port; it should have made four 8 second attempts to open to allow the burners to fire. If it opened and the pressure (3.5") was there, the burner should have lit o.k.
Above all let us know what you find, as sequence of operations are always changing.

yea thats what i was getting at why would a senior tech try 2 gas valves an still think thats what it is i mean what are the odds of getting 2 or 3 bad valves that do the same thing. thanks ill let ya no what happens.

[beenthere]

A manometer would be a help when doing a dianostic on this.

[Milk man]

need to give this guy a break. Because you are showing your ignorance as how some other equipment works. And some of you should know better.

My gas oven's HSI has to draw a minimum amount of amps before the gas valve to open and stay open.

[Milk man]

Goodman and maybe Lennox used an igniter and board that reduced voltage to the point the furnace would not light. Then on the next attempt the voltage was increased to the last ignition point. (As stated above)

[Airmechanical]

need to give this guy a break. Because you are showing your ignorance as how some other equipment works. And some of you should know better.

My gas oven's HSI has to draw a minimum amount of amps before the gas valve to open and stay open.

yap, and on the space shuttle before ignition takes place..........



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[erc tech]

This is most likely not the problem, But get the senor tech to check the condensate piping on this 90%er. if its not draining correct it will try and fire up by sputtering popping but the second pressure switch will not make. Also check the green gound wire that runs behind and routed back of the inducer housing. Its close to the heatexchanger box and I have found them badly burnt giving the gas valve a fit

[Milk man]

yap, and on the space shuttle before ignition takes place..........



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Are you sure they don't have a three tries for ignition before a soft lockout?

"Houston, we have a problem"
"Houston, the damn thing locked out again"
"Houston, I turned the key off and back on, it should light now. We can check the problem after the mission, during regular business hours."

[tinknocker service tech]

first i take it this is a new furnace
with these newer boards and ignitors the board does reat the ignitor
in some cases
some of the WR boards if you unplug the ignitor to test to see if voltage is been applied or when it is turned of the board will go into default and show ignito fault

you need to check the voltage at the board with every thing intacted

again is it propane or natral gas and what is the manifold pressure
is the ignitor lined up properly and are the burners clear and lined up

after te third valve what did he want to change next

if this is an older unit it may have a weak ignitor or the wrong one
amping the ignitor will give this info. If 3.0 or higher it is good, if less then 3 then time for a new one even if 2.99 it needs to be replace

being you are new then just kick back and watch. ask questions and learn
he isnt going to listen to you from what you are saying here

apply for pro menbership so you can realy learn things the correct way because there is a lot of good info there that cant be posted here

[hvactech1jm]

need to give this guy a break. Because you are showing your ignorance as how some other equipment works. And some of you should know better.

My gas oven's HSI has to draw a minimum amount of amps before the gas valve to open and stay open.

yea this is what im talking about i new some equipment did this. that shows what some of the other guys on here no. thaks