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Re: low high-side pressure, help
oh i dont know if it matters, but whan i closed the suction shut-off valve, the high side pressure DID NOT rise.
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Re: low high-side pressure, help
Is there a model# on the coil?
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
oh i dont know if it matters, but whan i closed the suction shut-off valve, the high side pressure DID NOT rise.
Did the low side pressure at the compressor inlet go into a vacuum?
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Re: low high-side pressure, help
which coil? but probly not there is not alot of id numbers on it
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Re: low high-side pressure, help
not much of a vacuum, 8 inhg
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
which coil? but probly not there is not alot of id numbers on it
The indoor coil.
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
the condensor is a model # gsh130361bb
the air handler is a model#
adpf304216ba
i couldnt find the exact app for this unit in the charts.
The ADPF304216BA can have a 2.5 to 3.5 ton coil.
As near as I can tell a 2.5 ton needs .065 and a 3.5 ton needs .078
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Re: low high-side pressure, help
i cant find any other numbers, so what do u think about the vacuum and pressure?
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Re: low high-side pressure, help
i was told that the air handler was built to range from a 2 1/2 ton -3 1/2 ton, making it a good candiate for my 3 ton condensor
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Re: low high-side pressure, help
I am not ready to blame the compressor just yet. We need to get the right orifice in there and see what the temps/pressures tell us.
The .078 is just too large, so we can assume that the coil is not 3 1/2 ton.
Unless you can find the btu rating for the coil we will just have to keep changing orifices.
I want to see that suction pressure down around 70 psi (or a little less) with about 15F coil outlet superheat.
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Re: low high-side pressure, help
well before i knew about the superheat method, i was setting the suction pressure at 70psi or little below, and when i put in smaller orifices(trying to raise the head pressure) i would loose a significant amont of efientcy. wich is how i ended up with the .82 orfice, the gave me the coldest vent temp.
it still really concerns me, that when i shut off the suction valve completly, the high side didnt change but the low side came down to a small vacuum. before i blamed the compressor, i would question the reversing valve, but i dont know how to check it.
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Re: low high-side pressure, help
You keerp mentioning the vent temp as if it were important.
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Re: low high-side pressure, help
if it dont blow cold then whats the point?
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Re: low high-side pressure, help
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
if it dont blow cold then whats the point?
The point is transferring heat.
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Re: low high-side pressure, help
call it whatever you like but the whole fact of the matter is that it cant transfer heat if it cant make heat, and with a head pressure of 180psi, it cant make heat. and when i close off the suction line and it still dont raise the head pressure, nothing will no matter how many orifices i throw at it.
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
call it whatever you like but the whole fact of the matter is that it cant transfer heat if it cant make heat, and with a head pressure of 180psi, it cant make heat. and when i close off the suction line and it still dont raise the head pressure, nothing will no matter how many orifices i throw at it.
Why would you expect the head pressure to rise when you shut off the suction valve?
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Re: low high-side pressure, help
Did you try another orifice today?
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Re: low high-side pressure, help
no i didnt have a chance, but i would expect the pressure to rise since the refrigerant has nowhere to go, it would be compressed in the coil, hense the pressure should skyrocket.
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Re: low high-side pressure, help
the only other orifice i have is a .73, but when i installed it before it acted like it had too much restriction to flood the coil with enough refrigerant to keep it cool.
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
no i didnt have a chance, but i would expect the pressure to rise since the refrigerant has nowhere to go, it would be compressed in the coil, hense the pressure should skyrocket.
When you shut off the suction the compressor has nothing to pump into the high side... and the high side is still cooling off and draining off into the evaporator. If anything the high side pressure should drop.
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
the only other orifice i have is a .73, but when i installed it before it acted like it had too much restriction to flood the coil with enough refrigerant to keep it cool.
Trust me, it will provide enough flow.
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Re: low high-side pressure, help
at this point i have nothin to loose so ill try the .73 again
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Re: low high-side pressure, help
hi
ithink there is miss matching btw the comp&air handler unit it appear that u have a large air hanling unit condenser came with this small orifice should b too small to handle the load u can check the comp brand & serial #
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Re: low high-side pressure, help
Quote:
Originally Posted by
tonyelian
hi
ithink there is miss matching btw the comp&air handler unit it appear that u have a large air hanling unit condenser came with this small orifice should b too small to handle the load u can check the comp brand & serial #
I tend to agree about the mismatch. The evap seems oversized for the compressor, but then this could be simply an orifice mismatch.
More worrisome is that the condenser seems oversized for the compressor.
If the compressor is undersized (under-capacity) for both the evap and the cond, that probably means the compressor is inefficient.
At this point I'm still hoping that the right sized orifice will show a good condenser load, but that may be just wishful thinking.
As mackking says, at this point there is nothing to lose by trying another orifice.
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Re: low high-side pressure, help
i put in the .73, set it to 15f superheat but i still have a high pressure on the low side (85psi with a 66f suction line)
the high side psi did rise but only to 225 psi. i couldnt get any more readings because it started pouring on me, but its still not bring the room temp down.
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Re: low high-side pressure, help
are u telling me that u think goodman installed the wrong compressor from the factory?
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
i put in the .73, set it to 15f superheat but i still have a high pressure on the low side (85psi with a 66f suction line)
the high side psi did rise but only to 225 psi. i couldnt get any more readings because it started pouring on me, but its still not bring the room temp down.
Any idea what the indoor and outdoor temps were at the time you took those readings?
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
are u telling me that u think goodman installed the wrong compressor from the factory?
No... an inefficient compressor is one with broken valves. The symptoms are the same as having an undersized compressor.
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Re: low high-side pressure, help
yeah the air in evap was 79 and the air out was 62, i know there is a good difference but it still dont seem cold enough to me.
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Re: low high-side pressure, help
how would i confirm an inefficient compressor
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
yeah the air in evap was 79 and the air out was 62, i know there is a good difference but it still dont seem cold enough to me.
And what was the outdoor temp?
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Re: low high-side pressure, help
i couldnt check it at the time because of the rain but i thinkit was around 85
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Re: low high-side pressure, help
As the temp in the house comes down the superheat will drop, so you should remove some refrigerant to keep it up around 15F.
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
i couldnt check it at the time because of the rain but i thinkit was around 85
225 psi at 85F would be an improvement. There may be hope for this system yet.
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Re: low high-side pressure, help
I have to wonder if pix would help. There may be a surprise in store. It has happened with other threads.
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Re: low high-side pressure, help
there may be hope but it hasnt brought it down and shut off yet, do u think this is any indication of how its gonna perform?
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Re: low high-side pressure, help
what kind of pics do u want?
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Re: low high-side pressure, help
Quote:
Originally Posted by
mackking
there may be hope but it hasnt brought it down and shut off yet, do u think this is any indication of how its gonna perform?
To get the charge just right, you need to adjust to 15F superheat when the house is down to your shutoff temp. We've been just ballparking it to compare orifices.
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Re: low high-side pressure, help
is the superheat effected by night time or daytime?