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Older York rtu Md# d6cg060n07946ecc
This unit will not light off! Started out with induce running,then ignition was sparking and I could smell gas at exhaust. So I replaced ign control thought the spark was weak. No go. Then I threw a gas valve in. No go. I cleaned the sparking contact point and made sure burner had a good ground. Pulled burner out and made sure pilot tube was clear. I blew through everything and felt it coming out pilot holes. I can see it sparking on the pilot tube and smell gas SO WHAT THE HELL. The last thing I did before it got dark was check inlet pressure at the gas valve. Without running it was 6.0. I know the other york rtu next to it had an inlet pressure of 8.0 not running and that runs fine. These rtu's have gas reg's before the gas valve. Tomorrow I want to see what the inlet drops to when trying to fire?????Maybe its dropping below 4.0 And Im getting 26volts at pv on the gasvalve so its not voltage issue. My next replacement part will be the reg. Dam this is getting crazy. Alot of part changing. Thats not how to do it. If you have a suggestion please let me know.
Thx Bill
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When you say pilot tube do you mean the crossover tube? Did you check the orifice? Pilot outlet pressure should equal inlet pressure. Are you sure the pilot is not lighting? Maybe it lights but there is no flame rectifiction. Could be a draft issue or HX issue also
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Yea crossover tube and orfice are clear. Pilot def not lighting. Could be hx Ill have to check tomorrow. So if inlet pressure is 6.0 the pilot pressure should be 6.0??Originally Posted by 2sac
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Cut 1/2" off both ends of your spark plug wire I've had these spark but not hot enough due to resistancein the wire plus you should check or replace the pilot assy./spark assy.
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Sounds like you have the exact same problem I have been having with the York im working on. If you are using LP gas then you should have 11" at the pilot outlet on the gas valve. Other guys have suggested the burner plate at the exhaust collector box, and the plate that is above the inducer fan could be rotted out. I inspected mine today and they were kinda rough but not rotted out enough to allow excess airflow across the hx. Damn you York haha
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Oh yes that was replaced too.
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Ok. Hx looks fine and so does the collector box. When trying to run, the inlet pressure is almost 5.0 natural gas.
I looked in there with a mirror and it looks like every once in a while the crossover tubing will lite a little bit near the spark but it will not cross over? I again cleaned out pilot tube and crossover. No luck. Maybe the cross over holes are to small? I'd hate to ream them out. Any other suggestions? New pilot assembly?
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Have you taken out the cross over tube and blown it out?
You could have a spider web or something else blocking it causing your
problem.
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I agree this is a common problem on the York RTU's. Sometimes I have to use a piece of wire to clean them out because air, or N2 pressure won't dislodge the spider eggsacks.
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Yea already ran wire threw. Blew out with air.
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Just had one that did the same thing. Make sure your flame sensors are positioned correctly. I had that issue also. It would light the pilot but then go out with no flame sense. The rod was in the flame but not enough of it. Moved it a little and it has been fine for week now.
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What was the reading from the controller to the PV? Corroded or broken wire maybe? Sorry. I just noticed you had correct voltage at pv.
Last edited by mikeybow; 01-19-2012 at 09:13 PM. Reason: 26 volts at pv
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I serviced a Dork unit a few years ago that would light if I was on site but not when I left. I went back every day for a week. Checked gas pressures, voltages, everything I could think of. After changing the gas valve and the pilot head/ignitor/sensor it STILL would not light consistently. I finally noticed the pilot flame was barely encompassing the sensor. I bent the flame deflector down a little to direct the flame onto the sensor.
That fixed it.
The angle of the deflector was the same on the old and new parts. I hate it when a new part doesn't work properly!
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I had a 5 ton York where the orifice that is pressed fit into the crossover tube was loose,would not light! replaced ok!
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I'm wondering if these flame sensors can vibrate/rotate within the ceramic??
I went on an old york rtu on monday and the flame sensor wasn't even close to the flame.
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Yea this orfice is loose, I can pull it right out. I just can't see it being that. It's worth a try though.
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If the pilot does light its only neat the spark. The flame sensor is at the other end of the crossover tube. The flame hasn't made it there yet.
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If you are telling us your inlet gas pressure when trying to light is bellow 5 inches wc you inlet pressure is too low.
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Yea I always thought I should have 7 inches but the gas valve says min 4 inches???
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You will lose 1 inch going through the valve and that would give you a minimum of three on your manifold side. If the unit next to it has 8'' then it should be no problem bringing this unit up and your problems will more than likely go away.
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