ReplyIs it a recip or scroll comp? If recip is there a start kit on it?
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Removed a 3 ton lennox r22 split system on saturday and replaced it with a luxaire 3 ton r410a system. There was no place to run a new line set so we flushed it with par flush and nitrogen and did a bunch of leak checks. We installed the A/H with a TXV and installed the new condenser, pulled a 300micron vac that held, opened the valves and added 3.5lbs of refrigerant. The unit was running PERFECTLY: 20 degree split, 11 degrees of subcooling, no problems what so ever.
So i decide to cycle the white rodgers thermostat we installed as well. Turn the temp down, let the unit shut off and then turn it back on.....The CFM comes on but not the compressor. Ok so i clamp up my amp meter, turn the disconnect back on and check it out: The compressor starts pulling LRA. At this point im pissed, so I shut the stat off again and wait a few minutes. The condenser comes on and is working perfectly!!!! I shut it off again and turn it back on.....compressor out on LRA again. I did this a few times and got the same results everytime.
What could be causing this problem? I was thinking that maybe the pressures inside the compressor are not having time to equalize which could be causing the compressor to pull LRA....Tell me what you think.
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Is it a recip or scroll comp? If recip is there a start kit on it?
I miss you mom and dad.
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Is the time delay working? The condenser shouldn't restart on a call for cool for about 5 minutes.
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Its a scroll.
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The damn stat doesnt have a 5min delay. I thought all stats had that
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Most new condensing units have delay built into the board. I'm not sure about Luxaire though. rtfm
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let it equalize
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Most condensers don't have a board for time delay. Time delay cones from stat which this one doesn't have. Almost any system that tries to start right after being turned off won't nothing is wrong with the equipment. Just needs tine to equalize between cycles.
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thats what i figured, thanks for your help guys
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Agreed. If you want you could add a time delay, there's usually plenty of room in the control cabinet.Originally Posted by Crazecodyk
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410A
[QUOTE=dcx516;14166851]Removed a 3 ton lennox r22 split system on saturday and replaced it with a luxaire 3 ton r410a system. There was no place to run a new line set so we flushed it with par flush and nitrogen and did a bunch of leak checks. We installed the A/H with a TXV and installed the new condenser, pulled a 300micron vac that held, opened the valves and added 3.5lbs of refrigerant. The unit was running PERFECTLY: 20 degree split, 11 degrees of subcooling, no problems what so ever.
Not sure on length of line set but 3.5 pounds seems like too much too me. We usually are adding ounces to ours, not pounds.
Change out the stat, or buy a time delay relay.
As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84
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I would assume that the new condenser with R410a came factory charged? So the addition of 3 pounds and 8 ounces of to the new system would tend to tell me that you have a hell of a long lineset. If this is the case, you may need to touch base with the manufacturer as for what in addition may be required to operate this unit. Possibly hard-start kit, liquid line solenoid, etc. Many manufactures have Refrigeration Piping Manuals to make sure that you are not only properly sizing the piping, but also following good piping practices and adding necessary components to help the compressor stay within it's operational envelope.
Like said earlier 3.5 pounds of R410a seems like a lot. It is VERY EASY to overcharge a R410a system and if per chance this condensing unit uses aluminum micro-channel outdoor condenser...you could be in a whole world of hurt.
As with everyone else....a time delay is a MUST.
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Is that line set over a hundred feet? That's how long it would need to be above 15 feet for it to require that much gas. If so, then like said above you have other problems to deal with. A time delay is nice but nothing is going to help that compressor if it is grossly overcharged.
You need to put the phone down and get back to work!
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A scroll starts unloaded.
So I don't think its that alone causing problems.
Banned
FIRST OF ALL you need to make sure the system is equalized before you are turning it on and off....
Def. sound like an installer with all this talk of locked rotor amps etc.
if it was pumped down to 300 microns I don't think LRA would be a problem.. UNLESS you are not allowing a delay.
At this point I would suggest a hard start and crossing your fingers..
Since your out in the field dealing with some old r22 lineset, you need to follow your heart...
good luck...
No text book can explain your situation...
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the only problem is the fast intermittent starts. eliminate this rapid recycle and problem is gone
i do however suggest a 5-2-1 hard start and a time delay
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It takes a minute or two to for it to equalize.
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Hmmm. I have never ever witnessed a scroll not start up within seconds with no addl start components.
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Scrolls have check valves in the discharge to keep them from spinning backwards like the old Carlyle carrier scrolls( the green ones) when they shut off. Put a hard start on it and remove the exceeds refrigerant. York Trane carrier Ducane, pretty much all condensers except goodman have time delay built into defrost control board. Apparently yours does not but hard start will roll that compressor over even under loaded startups.
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I have a stupid question....did the Luxaire call for the same size line set as the Lennox?
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