York RTU Nightmare

[qwerty hvac]

Got a call today from another tech in our company who is having heat issues. When he got there the inducer was running and the ignition module was sparking and gas valve was open but not lighting the burner. So he took apart the burners and cleaned the pilot burners and orifices. After putting it back together it still would not light. He finally got it lit with a torch and it ran fine but would again not refire after the call for heat. He gave me a call and I suggested that it might be an issue with the pilot burners or the electrodes. So he replaced the parts I suggested. When he went to start it up again he now had nothing at all except the inducer running. The ignition modules had no power to them for some reason. I have not been there yet but was trying to figure out what happened. He did not disconnect any other wiring except the electrode. If anyone has any ideas or the wiring diagram that would be great.

Model #D2CG180N32025ECC
Serial # NKDM085916

[allstar08]

You need a lot more info. What was the gas pressure? What was the pilot pressure? When he lit the burner with a torch ( not smart by the way) what was the gas pressure. When he put the new ignition module in was it a factory Johnson Control unit or a like in kind?

[DPinst]

Centrifugal switch on the ventor motor ,roll out switch ,or high limit could be the reason for no power to the module. As to not lighting sometimes the spark generated by the module is incorrect and is not enough to ignite the gas .

[qwerty hvac]

You are right about not being smart.. He only changed the electrodes and the pilot tube.. I have no other info but that for now. But I cant figure out why he has no control voltage to the ignoition modules when they were working before this.

[mikeacman]

Did he have it running "hot" and shut the disco off before shutting the heat off and letting it cool down ? He may have caused a limit to trip . Maybe he disturbed some wiring and doesn't know it yet.

Should be easy to trace down with the schematic .

I wonder if the pilot valve is opening and he faked it out with a torch . You know he's getting gas because he got the main burners lit . I would still check incoming and manifold pressures.


Good luck.

[qwerty hvac]

Centrifugal switch on the ventor motor ,roll out switch ,or high limit could be the reason for no power to the module. As to not lighting sometimes the spark generated by the module is incorrect and is not enough to ignite the gas .

He said the centrifugal and limits were all good. Voltage does not seem to be present before the limits. I am thinking he might have a bad relay but I have no diagram to look at.

[qwerty hvac]

He had it running while he went to go get parts. When he came back it was shut down but inducer was running. He changed out parts and it would not fire at all. He said he checked all the safeties and they are good.

Did he have it running "hot" and shut the disco off before shutting the heat off and letting it cool down ? He may have caused a limit to trip . Maybe he disturbed some wiring and doesn't know it yet.

Should be easy to trace down with the schematic .

I wonder if the pilot valve is opening and he faked it out with a torch . You know he's getting gas because he got the main burners lit . I would still check incoming and manifold pressures.


Good luck.

[ar_hvac_man]

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[qwerty hvac]

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Thank you. printing it off now

[timebuilder]

Heat relay.

[qwerty hvac]

Heat relay.

That's what I was thinking.


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[Theref]

I have a York Training manual for a D1CG 15/20 ton unit with wiring diagrams It may be similar to the D2 series you have. The larger units have heat relays. I can enlarge these drawings and fax them to you if you like?

[qwerty hvac]

I have a York Training manual for a D1CG 15/20 ton unit with wiring diagrams It may be similar to the D2 series you have. The larger units have heat relays. I can enlarge these drawings and fax them to you if you like?

Thanks. I have the wiring diagrams now. I appreciate your help.


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[Theref]

I noticed you said there was no voltage before the limit. If that is the case the 24 volt circuit breaker has tripped. The limit always has 24 volt power to terminal #1. If it trips it puts power to terminal #2 and energizes the TDR which then brings on the indoor blower

[qwerty hvac]

That I'd what I did not understand. Maybe he explained it wrong to me. He did say the breaker was not tripped.


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[timebuilder]

He needs some e-lec-trick-al diagnostic learnin'.

[Black Iron]

I have had similar problems with these units before. Look for corroded common/ground terminals and clean them, as well as clean the terminals on the flame rollout switch it always helps. Another thing i have found is that new source 1 spark electrodes tend to be spaced just a tiny bit too far away from pilot carry over tube, try bending the electrode in a fraction. Good luck!

[Mike19]

Last post is right on, I have had the same problems. When he did have it sparking, was it both stages sparking and neither would light? This is probably unrelated, have you checked the heat exchanger for cracks, we have had to change it on just about every one of those units we encounter.

[qwerty hvac]

I have had similar problems with these units before. Look for corroded common/ground terminals and clean them, as well as clean the terminals on the flame rollout switch it always helps. Another thing i have found is that new source 1 spark electrodes tend to be spaced just a tiny bit too far away from pilot carry over tube, try bending the electrode in a fraction. Good luck!

I will check that out. I did not even get to that site today. Have no idea if he got it running either. To busy with my own work.


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[qwerty hvac]

Last post is right on, I have had the same problems. When he did have it sparking, was it both stages sparking and neither would light? This is probably unrelated, have you checked the heat exchanger for cracks, we have had to change it on just about every one of those units we encounter.

I have changed a few York HE. They are not the easiest.


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