Lennox minisplit driving me insane

[Cabral255]

I have a 2 head minisplit I installed for a customer. The upstairs unit,9000btu blows 40degree air but when I turn the temp up to 85 it just keeps blowing cold air. I stood in front of it for 5 minutes. The downstairs unit, 18k btu, was only blowing 63 degree air. I checked the factory charge, it was fine. I switched the unit that wasn't working to a different port on the condenser. I vacuumed and recharged using a scale. The downstairs unit was then 45 degrees but then went back up to 63 and upstairs unit won't stop cooling. Wtf

[pecmsg]

How did you check the charge?

[Cabral255]

I got 98 ounces out of the unit. That matches the factory charge. Each line set comes pre-charged for 25 ft. Each line set that I had was under 25 ft

[pecmsg]

Line sets pre charged on minis?

[Cabral255]

The line set isn't precharged. You open the master to release the charge into the line set after you vacuum them down below 500 microns.

[martyinlincoln]

Did you call tech support?

[Cabral255]

I will call them on Monday when they are open. I just finished working on it and it's driving me a little crazy so I figured I would see if anyone here had any input in the meantime.

[kangaroogod]

What happens when both units are calling for cooling? Do they both blow 40deg air?

'The more you know, the more you realize you don't know'

[Advanced Response]

Kang,
That is what I was thinking too, seen that issue many times on multi head minis..

I think you may be into something.
J

[Cabral255]

While I was recharging the unit both heads where set to to cooling. As soon as I had the correct charge I went into the home and both units where in the 40s. I let them both run for about 20 mins while I put.my equipment away. I went back inside and checked it one last time before I shut them both down and the larger unit was 63 degrees. The smaller one was still in the 40s.

[knave]

It was possibly reducing capacity being near set point? Oh. Yes. Triple check your wiring.

The zones may be crisscrossed

[Cabral255]

Wow that must be it. I must have wires 1,2,3 in the right places but the units must be criss crossed. Boy do I feel like a ****ing idiot! Easy fix though

[Cabral255]

It still doesn't make sense though because when both units are calling for cooling even if the wires were crossed both units should still be blowing cold air and they are not.

[knave]

They start modulating before they reach setpoint. Like 3° above on one manufacturer.