It may have been possible your valve was leaking as you stated. So you had a low charge. Then when you changed the drier, if you did not use a N2 purge, you may have gotten crap into the system and took out the TXV.
I didn't even think of that, i'm just a little surprised by it flooding back, i've never seen a manitowoc exp. valve fail like that, I've seen plenty that starve the evaporator, and had one flooding back that was solved by a little electrical tape around the bulb insulation. I'm sure its possible, but most of the time the crap plugs up the strainer in the valve and they starve the evaporator.
The 76-0019-3 should be the part number, a machine that old would have come with an alco valve from the factory, was the valve the original Alco or was it changed to a Danfoss? If so, make sure that the valve is installed with the liquid line coming in the bottom of the valve, dome on top. You will probably need to install a j-tube to make that work. Also, double check the insulation. A lot of guys put the insulation boot that fit the Alco over the Danfoss, which tends not to work. At the very least, if you don't want to order the boot, wrap it in several layers of pipe insulation tape. Finally, double check the bulb mounting. While I am assuming that this valve is bad due to the pressures being that far out of whack, you would be surprised how much the proper mounting as well as insulation will affect these machines.
look at the cap tube that connects the bulb to the body, stainless is danfoss, copper is alco. As for the hot gas valve, feel the line going in, and you can feel the line going out to see if it is warm. the outgoing line might not be warm if the hot gas valve has failed, but the incoming one probably will (if I remember correctly). They changed those alco hot gas valves to danfoss too, I think the Alco ones were a little more reliable, they just have a tendency to leak around the stem and where they screw together. Easy way to tell which hot gas valve it is is that danfoss hot gas valves have cube-shaped coils
I should be putting this all in the same post, but today kicked my butt.
Buy a set of stubbies to use just for IM's and small critical charged systems. Using your regular manifold will cause you to lose about two ounces just by hookin em up.
You only lose a measurable amount of refrigerant when placing gauges when you attach to the liquid side. Vapor amounts in hoses are insignificant. I have a ball valve end on my high-side hose. Close this valve then open the high side to the low side through the manifold. All your liquid will be drawn back into the system. No need for stubbies.
The valve was a danfoss and someone installed it incorrectly. There is no J tube, and it is feed above the valve with the powerhead going horizontal. The temps I took across the refrig lines lead to the TXV valve was over feeding the evap and causing the compressor to sweat and some frost to accumulate on the head.
i have a QY0424A model! i am an electrical engineer and extremely curious about HVAC and refrigeration! the problem with the machine i have is it makes a little bit of ICE like 4 and sometimes even 7 or 8 sheets of ice and then quits! i read the cleaning instructions and cleaned it and its still the same! i finally gave up and called a service tech - he could not find where to plug in his guages to the high and low side! i had to tell him! but before he did anything he was so sure that its a compressor problem and that it needs replacement - he quatoed me $1200 for compressor and 400 labor! so i saidd thank you i will shop around - i stumbled on this site and i think these is a lot to learn but since i dont have the education or training needed in addition to test gauges and tools, i am hoping ssomeone can help me diagnose from their experience...what couldd possibly be the root casues for the sympotms and if you can ecommen anyone from Huntington Beach area in Southern California!!! thanks for all your help
These are good ice machine companies near you:
Sorry for the Caps
AUMILLER INC DBA QUALITY AIRE 7245 GARDEN GROVE BLVD - UNIT G
GARDEN GROVE, CA 92841
Proximity: 4.93 miles Phone: 1(714)897-0083
Email: ICE MACHINES AND RELATED PRODUCTS INSTALL
RELIABLE ICE EQUIPMENT 13337 E SOUTH STREET #413
CERRITOS, CA 90703
Proximity: 10.72 miles Phone: 1(800)577-2585
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