RTU 48TJE KEEP FREEZING

[fiscalito71]

Hi everyone, hard to learn something new by itself, unfortunately that is my case. I was checking an carrier RTU and i could not figure out why was keep on freezing on me. Finally I evacuate all the refrigerant and came up that the amount of refrigerant was exactly the exactly the same as the label in the unit said, 7.9 lb. So I got to the point to assume that it was getting freeze up because the inside of the building was not to hot???? because, nothing else was wrong. All tips will be greatly appreciated.

[Baycienda]

I doubt a low load would cause it to freeze up. Check your air flow, blower motor, and duct work.

[fiscalito71]

Thank you. I did and everything seems to be find. That's why I was wondering if outside temp will affect that.

[jpsmith1cm]

Did you take any readings on the unit other than pulling the charge and weighing it?

The answer lies within that data.

[sprmktrefertech]

Fire damper slammed shut....happened to me.

[timebuilder]

We need all the numbers.

You did gather the numbers, right?

For example, the temp diff across the evaporator when it was thawed and recharged.

Superheat.

Subcooling.

Outdoor and indoor.

Stuff like that.

[TMS134]

More info needed. What was the outdoor temp? Is there a fan speed control for the condenser motor for cool weather operation?

[fiscalito71]

Thank you every one for your advice, I really apreciate it. Is hard when you have to learn in your own. But thanks God and those who create HVAC TALK !!!!!!!!!!!!!!!. Thank you again.

[Tiger93rsl]

I've had a lot of problems with the headers plugging up on those units.

[kimosobee]

Before you emptied the units freon did you check temperature on both sides of the liquid line filter dryer to see if there was a temp difference? The filter dryer could have debris or to much braising leaked silfloss into filter itself creating a restriction How old is the unit?
Good Luck! Kimosobee

[fiscalito71]

Thank you, and yes I did check the filter, it was ok. no difference in temp.

[Assassin]

Tell them that they should look at getting a Lennox. Ha-ha-ha!

[timebuilder]

Tell them that they should look at getting a Lennox. Ha-ha-ha!

Everyone has an economic point-of-value. Lennox is not the right choice for some retail clients.

As far as durability, I replace just as many condenser fan assys on Lennox as I do Carrier. In fact, I was at a location last Monday with seven bad fans out of five RTU's. Today, I replaced a completely blocked, and I mean 100% blocked filter dryer in an LGA.

Good units? Sure. Perfect? No way even close. In fact, come winter, those JCI blue boxes are a staple of my no-heat calls on Lennox units.

I'm gonna miss the blue boxes....