Maintenance & Repairs - 5 hours ago
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So I'm in an HVAC class. My lab was a unit change out. Everything was going smooth and easy, until I tried to raise the head pressure to 278 psig.
The first time I got my head pressure up around 278 psig. While measuring my subcool(which was fluttering around 20 degrees) the high pressure switch cut out. After that It cut out at around 160psig. I bypassed the hi/lo pressure switches, because they kept tripping, and raised head pressure to 200 psig. Above that and the compressor cuts out while the condenser fan keeps blowing.
I weighed in the charge of 5.8 lbs of R-22, like the label on the unit called for, if anything it is overcharged. I pulled a triple evac. It is not on me yet to troubleshoot this unit, but I hate failure. This one has two of my instructors suspecting different causes; bad compressor or undercharge. Any ideas?
To raise the head pressure, we wrap the coils with plastic and limit airflow. I say it is overcharged because 5.8 lbs is a complete charge with 25' of lineset. This unit has approximately 19' of lineset. The evap coil was not replaced with the condenser. The TXV works fine, it maintains 10 degrees superheat.
I think I got everything.
The filter drier is just a standard issue. About the size of an orange. The sight glass has a few stray bubbles, which I have received mixed information on. A short time instructor said a proper charge should show no bubbles, another instructor said a proper charge would show some bubbles.
The subcool number does show an undercharge...either a coolant loss or I had the scale set to kilos?
I think it was a potential relay. All those little black boxes look the same, and I could not see the wiring diagram without removing it from the unit.
discharge temp. was around 85-110, the higher number with higher pressure.
hermetic, scroll, 208 volt, high temp, used residential unit. We have dozens of A/C's, I swapped out a 13 SEER unit for an antique 12 SEER Rheem.
I don't remember the amp draw, but it did increase as pressure rose.
This problem developed near the end of the day. So we didn't have time to start troubleshooting. School is closed till Monday, but I have been pondering this since last night.
From the questions you have led me with, I tend to suspect the compressor.
The compressor was extremely hot to the touch. I think it was a potential relay. I could not read the schematic on it.
I admit I am a rookie with no practical field experience.
evap pressure stays steady at 70 psig. The pressure rises to around 80 psig when head pressure is forced up to 200 psig.
Decorating & Remodeling - 9 hours ago
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I'm buying fabric for my couches and I wanted to know if a blend of wool and polyester would be a good fabric.. I want something that is colour durable, easy to clean and would last a long time..
OH and something that wont lint up when i put it in the wash..
if anyone knows of such fabric please let me know..
thanks in advance
Do It Yourself (DIY) - 11 hours ago
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I'm not sure if I make sense to you, this is hard to explain.
Basically there is a hole or groove about a inch deep in the sheetrock where he failed to snap the board clean. The grove is located in the middle on the ending. Now when I tape over this I can sorta see that I'm taping over a hole in a wall. I feel like this is not the proper way to do it and it can easy be "punched" through later on.
What can I do to fix this gap so I can tape over something solider and the paste?
Cleaning & Laundry - 12 hours ago
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I always wear them without socks because they are so warm and fluffy inside so Im thinking I should clean them, can they go in the washing machine and the dryer?
Decorating & Remodeling - 14 hours ago
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Cleaning & Laundry - 14 hours ago
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Cleaning & Laundry - 14 hours ago
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It pauses for about 3 sec about every minute during the washing.
Decorating & Remodeling - 16 hours ago
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someone knows who is hiring.i do framing metal stud,drywall,& T bar suspended ceiling and also i have my own laser for T bar ceiling i have more than 10 years experience i am available in east wenatche wash. thanks
Garden & Landscape - 16 hours ago
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I always thought you were supposed to trim them in springtime, but right now those little spindly branches with no leaves on them look pretty easy to trim to the height I want them at ......
Do It Yourself (DIY) - 16 hours ago
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Hi. I was at work and, in a fit of utter stupidity, I went to the swtichboard and flicked some of the trip switches off. Now they won't switch back on again. I tried to switch them on and they just kept going back to off.
Please help before anyone notices that nothing is working. Is there an easy way to get them back on again? I don't want to get the sack. I think I might just pretend it was a storm that did it. But I don't know if I can get away with it. Please help!
I think the switches are right over into the off position already but I'll check.
I think I have to call in the electricians and pay for them to fix it (in the middle of the night), because if the company can't function due to a strange lack of electricity then it will cause a lot of problems and then people will get angry and I will have to hide in the cupboards again. And I don't want to do that because it's very uncomfortable after the first few hours.
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