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!
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.
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 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.
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.)
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".
I spoke with a tech at Nordyne about the units that are installed, and he insisted that they are a compatible match.
Originally Posted by iraqveteran
I do have a 608 universal cert..
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?
Originally Posted by mdengineer
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.
Originally Posted by DPSwitch
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 :(.
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.
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.