ReplyNot much to make an opinion about.....
we still don't have nearly enough info.
You are aware it is likely low, but you're main concern should be getting the leak fixed.
When it's fixed the tech should know how to tune it.
Regular Guest
Finally got some time to do some PM on my system for the summer. Washed/cleaned outside coil, checked inside coil, replaced air filter, and checked insulation on the suction tube.
I just checked pressures and temps after letting the unit run for a good 10-15minutes, and here is what I have:
liquid pressure: 150psi
liquid line temp (at outside unit): 84degrees
Suction pressure: 60psi (varied between 58-60)
Now, the system at my house is a bit of a frankenstien. The outdoor unit is a Frigidaire FT3BD, the air handler is a frigidaire B5BM. None of Nordyne's literature mentions these two together, and the FT3BD charging graphs do not have any data for an indoor TXV. So what I did was take the charging graph from their FT5BD literature (which uses the same ZRK3 compressor), which does have a graph for TXV charging, and used that. I attached the graph.
It appears the system is about 25psi low. I also measured temperatures at the air inlet and outlet of the air handler. Incoming is 75degrees and out is 64 degrees. System is cooling fine, but I wanted to make sure it is working at peak efficiency.
Just wanted to get some opinions here before I call to get it charged!
Professional Member
Not much to make an opinion about.....
we still don't have nearly enough info.
You are aware it is likely low, but you're main concern should be getting the leak fixed.
When it's fixed the tech should know how to tune it.
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Professional Member
another engineer trying to do HVAC......
its sad that those that make a decent living must find every possible way to save a penny.
25 psi low huh, yeah thats it. Now convert that to pounds at barometric temp, add your sea level, divide by the current temp and add the amout of rain (in centimeters in the last 24 hours) and you will know how many metric tons of "freon to add.
Get a real tech out to diagnose the problem. And to fix it properly.
I fully support the military and the War on Terrorism.
If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.
If you do know, then do. But do it right. Otherwise, you may not be doing it long.
Regular Guest
I actually don't believe it has a leak..
The system was installed in the summer, and was working very well. When the time came, I had the installer back out in the winter to verify heating operation. They said it was overcharged, and took some refrigerant out. According to them, it was due to the outdoor unit having a piston and the indoor unit having a TXV.
Anyways, I think they took too much out, causing it to be a little low during cooling operation. Trick is finding that happy middle between cooling and heating operation.
What other info would you like about the system? Outside unit is 2.5ton, air handler is a 3ton. R-22 system.
Professional Member
ok.,....
if you need to be put on a "freon" agreement. Then you either have a system mismatch or you have an improperly sized lineset.
Thats pretty easy.
next, you need to have the techs doing the maintainence. This is not a DIY site and we cannot help you as a DIYer. Not to mention, you technically just voided your warranty when you began taking pressure readings. And EPA regulations.(unless you have EPA cert.)
I fully support the military and the War on Terrorism.
If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.
If you do know, then do. But do it right. Otherwise, you may not be doing it long.
Regular Guest
A real tech huh? Like the 8 companies I called to come out and do the initial estimate, and all but 2 wouldn't do or didn't know what a manual-J was? Or like the company that just installed my neighbors unit and vented the entire system to the atmosphere?Originally Posted by iraqveteran
Thanks for adding meaningful information to the thread.. I didn't know the title of this forum was "You're not allowed to know, now go away".
Regular Guest
I spoke with a tech at Nordyne about the units that are installed, and he insisted that they are a compatible match.
I do have a 608 universal cert..
Professional Member
You may have a seasonal charge imbalance that needs to be corrected, for that.....you do indeed need a real tech.
Are you EPA certified?
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Professional Member
Ok
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Regular Guest
I was thinking along the same lines... Thanks. Had I known as much as I do now I probably would have requested models that were matched as per the documentation. Hindsight and all that.
Also wanted to appologize for my previous post. I am attempting to get as much information as I can before I consult an outside person. In my real line of work, I prefer the person I am working with is knowledgable about the problem we are trying to solve. It has been my experience that most of the people I invite over to inspect my system do not wish to discuss the details and instead only offer a price. I am not out to second guess anyone, but do like to be informed more than just "its fixed, gimme $300".
I decided to get my cert so that I could check my system myself, as well as my parents. I intend to keep a log of my readings to help troubleshoot future issues. Sorry if I came across as someone who decided to buy a goodman online and install it himself.
God Speed, Jim. We'll miss you - 2-26-23
You might have a seasonal charge imbalance. But you shouldn't if its a matched system as Nordyne said.
But, look at the fan data plate for that blower. Those are weak blowers, usually only rated at .4" TESP. Meaning you might have very low air flow. Which could make it seem over charged in the winter, and under charged in the summer.
Professional Member
Very good points
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Professional Member
Oh md.
If you are going to check those pressures yourself. Do yourself a favor and don't use standard charging hoses.
Get yourself some little stubby gauge connectors or the little short 5" or 6" hoses.
Every time you put the gauges on you are taking refrigerant out of the system, especially on your liquid line. Lose a hose full of liquid on several checks and it adds up.
Since you arent adding or taking away, you dont need to use a manifold.
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Professional Member
I've said it before and I'll say it again.........
Oh yeah, and I never said everyone in HVAC are "professional".
You can log your findings all you want. All your going to find is that everytime you checked your own pressures, you lost refrigerant. And when the system fails, I highly doubt the tech that comes out will want to see your pressure log. That tell us nothing other than the compressor was pumping.
You want to start a log, go ahead. But personally, I wouldn't use a HO logbook when I go to diagnose a problem. Thats just me.
Oh and I've been trying to get the forum name changed to "We know it all.....and don't you forget it!!!"
I fully support the military and the War on Terrorism.
If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.
If you do know, then do. But do it right. Otherwise, you may not be doing it long.
Professional Member*
mabee it was not overcharged to start with
Regular Guest
Good points. Do you have any sources for the short hoses? The shortest I've been able to find is 36". PM is okay if we aren't allowed to post links on the forum.
Regular Guest
That did cross my mind. I don't have any measurements from the winter, so I'm hoping once the system is at the proper level for cooling I'll be able to check this coming winter to see if it actually was out of spec.
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