Author Topic: York RTU...  (Read 2193 times)

Offline nash668

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York RTU...
« on: December 31, 2015, 06:04:14 AM »
Spent more time yesterday than i should have on a rooftop trying to figure out why in the hell it kept tripping on high limit. Manual says gas should be at 3.5" on hi fire. Turned it down to 3.0-2.9". Couldnt increase fan speed due to duct noise being the issue or having air blow on you while you're eating. (Restaurant) Manual said nothing for LED codes. Only thing i could figure out was to keep fan on all the time to keep heat exchanger cool. I am probably missing something or the unit has a ghost

Help!

Offline Admin

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Re: York RTU...
« Reply #1 on: December 31, 2015, 10:21:09 AM »
Did you check the temperature rise?  Sometimes there's a filter hidden inside that might be dirty.

If the filter, airflow and temperature rise are good then it might just be a bad control board locking out.  Was the limit actually open when you were there?  There may have been a dirty filter in the past that caused the limit to trip and reset repeatedly.  The limit may just be weak and worn out.

Ductwork noise is sometimes a sign it's not big enough to handle the appliances airflow.  Maybe it's a bad design / install that causes the unit to overheat.

Offline nash668

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Re: York RTU...
« Reply #2 on: January 01, 2016, 01:52:02 PM »
Forgot to mention the unit was installed 2-3 weeks ago. Filters were brand new. Did not check temp rise. Other thing too is that there were 2 alarms showing up after a while. Said coil 1 and coil 2 were locked due to freezing up.

That's what it came down too. Either the unit has a shitty board, has defective sensor the ducting is sized to small.

Just frustrating when you tell the client "yeah hey.. there is something wrong but I don't know what it is".

Offline Admin

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Re: York RTU...
« Reply #3 on: January 02, 2016, 09:07:21 AM »
Is there an economizer stuck open?

Offline viking

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Re: York RTU...
« Reply #4 on: January 02, 2016, 11:53:56 AM »
I'd check everything mentioned and also if you think faults are erroneous I'd also check for proper voltages (line and control) and proper grounding.
If it's a re and re, is it bigger unit than what came out?

Offline Xiaopig9

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Re: York RTU...
« Reply #5 on: January 08, 2016, 07:58:37 PM »
When does hi limit tripping happened? How  long for the blower delay? You say "keep fan on all the time", it can solve the problem?