Trane Voyager RTU Heating Issues
I got an issue with an older Trane Voyager pack that isn't lighting up in heat.
The model is YCD150B4LOBA
The ignitor was bad, so I got a new one, and installed it. On first ignition trial the burner lit for about a second, then went out. It hasn't lit up since,just three trial ignitions, then goes into lockout.
I put my ohm-meter on the ignitor and get 65 ohms. The ignitor gets 125 volts to it during ignition trial. The manifold gas pressure is -2.5" w.c. when the combustion blower is running during pre-purge. The gas pressure goes to -1.3" w.c. when the gas valve is energized.
I took out the ignitor and watched it "glow" during ignition trial, it gets bright orange and doesn't have any "hot spots" or cool spots. I removed the combustion blower and cleaned the little diagonal metal screen. The large diffuser grille is clean. Removed the brass orifice and did not see any obstructions. Put it back together and have same result-- does not light. Any suggestions or input much appreciated.
I had a situation that was similar to yours. A co-worker asked me to give him a hand on a voyager that wouldn't light. He had replaced the igniter and the gas valve and it still wouldn't light. We removed the combustion motor and inspected the mesh screen ad it was clean. Checked gas pressure just like you did, and everything was good, it just wouldn't light. We ended up removing the the combustion motor. And then we removed the the large circular plate that the combustion motor is bolted too. It has 5/16 bolts and rectangular shaped metal strips that hold this circular plate on. When we removed the plate there is a very large diffuser wall with tiny little holes in it where the gas passes through and then ignites Down stream from the diffuser. All the little tiny holes were plugged up. We blew them out with nitrogen and reassembled the machine. She lit up like a champ. Hope it helps man. Let me know what you find I'm curious.
gas psi too high
do you have the combustion book?
It`s better to be silent and thought the fool; than speak and remove all doubt.
Thanks Er14ic, I think the diffuser plate was clean, but I'll take a nitrogen bottle up with me next visit to be sure.
No I don't, if the manifold pressure goes from -2.5" w.c. to -1.3" w.c. when the gas valve is energized, that's too much gas pressure? Do you know where this combustion manual is available at?
Originally Posted by dandyme
Check your E-mail
Originally Posted by chrisnorris
Originally Posted by second opinion
Sounds like your gas pressure is too low. You should have -.2 wc when the gas valve opens. Make sure you have enough gas pressure going to the gas valve. Check between the reg. and the gas valve, if it is in the range required, adjust the gas valve to increase the pressure so you have -.2 wc.
You're absolutley right, hands.
Originally Posted by hands
When the gas valve was energized, I had -1.3" w.c.---there wasn't enough gas being put out to raise that negative pressure up to -0.2". Tried adjusting gas valve's regulator to increase pressure to no avail. Looks a like new gas valve.
And a side note if there's Voyager newbies like me reading this...
I went back to that unit with my supervisor.That morning I gave a quick read of the combustion manual that secondopinion sent me that morning. What I missed is that decimal point before the -2" w.c., and had the mistaken impression that the manifold pressure was supposed to be -2.0" w.c. wrong!. As my supervisor pointed out--its -0.2 inches ,thats 2/10ths of an inch w.c.----just a breath under 0.0"
I write this in hopes that somebody else doesn't make the same mistake.
I've been in commercial only a few months and this is my first time dealing with a Voyager's gas pressures. Everything I've dealt with before in residential was 3.5" or 10".
Learn something new every day.
Thank you all for your responses!
Before you change the gas valve, check the incoming gas pressure while the unit is trying to light. If it drops to zero when the gas valve is energized, you have a supply problem, not a gas valve problem.
And in the future, please post technical threads in the Pro forum instead of open forums.
Gas supply pressure was fine.
Originally Posted by chuckcrj
I should have mentioned that in previous post.
Just to clarify, you watched the incoming pressure through the complete lighting sequence?
Originally Posted by chrisnorris
Worry is a really gross misuse of one's imagination. -- PHM