Central AC not cold enough, pro gets confused


  #1  
Old 06-20-10, 09:17 PM
S
SZ8
SZ8 is offline
Member
Thread Starter
Join Date: Jan 2007
Location: texas
Posts: 71
Upvotes: 0
Received 0 Upvotes on 0 Posts
Central AC not cold enough, pro gets confused

Hi, all,

Today I noticed that one of the two AC that for my
downstairs does not stop for the
whole afternoon. The temp set to was 78 and the room
temp stayed at 80. Outside was around 99 here in Dallas.
I noticed that the cold copper connector at the compressor
feels a bit cold but not very code (without condensed water)
while the other normal unit does have condensed water. The air
blown out by the fan still feels warm.

The AC is a carrier 5 tons installed 13 years ago.

I called a pro and he measured the high and low ends of
the ourside unit and it reads 111 and 205 (psi). He seems
a bit confused say that the low side is way too high and he
suggested the compressor valve is worn and I need a new
system.

But then (after he left), I read the plate on the unit and
it says "design/test presure gauge 300, 150 psi". Does that
means my unit simply needs recharge of foen?

Thanks a lot.

SZ
 
  #2  
Old 06-20-10, 10:04 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 6,532
Received 95 Upvotes on 88 Posts
It probably is bad valves in your compressor. A simple test would have been pumping the system down.

 
  #3  
Old 06-21-10, 05:29 AM
S
SZ8
SZ8 is offline
Member
Thread Starter
Join Date: Jan 2007
Location: texas
Posts: 71
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks for reply. I guess

my questions is: if low side is 111 psi given the plate
saying low/high test gauge of 150/300 psi, can we
say low side is not low enough?

Thanks again.
 
  #4  
Old 06-21-10, 07:40 AM
C
Member
Join Date: Aug 2008
Location: Texas, California
Posts: 1,423
Upvotes: 0
Received 8 Upvotes on 8 Posts
Your AC tech may be right, you want to see something like70-78/220-240 on the gauge in a hot 99 degree day. Check the compressor AMP draw to verify.
 
  #5  
Old 06-21-10, 01:11 PM
S
SZ8
SZ8 is offline
Member
Thread Starter
Join Date: Jan 2007
Location: texas
Posts: 71
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks for the info. A second guy came

and checked with a similar conclusion.

I've decided to have it replaced.

Thanks again.
 
  #6  
Old 08-09-12, 11:29 AM
A
Member
Join Date: Aug 2012
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Not Cooling Enough

Your pressures should be 70-80 and (at 99 degres) 285-295 psig.
In your case you have High Suction pressure and Low Head pressure.
Possible Causes:
1) Refrigerant undercharge
2) Water on the condenser coils
3) Inefficient compressor
4) TXV stuck upen
5) Iced evaporator
6) leaking check valve
7) stuck fixed bore piston
8) Refrigerant overcharge
9) Missing or incorrect piston size
10) Leaking reversing valve
11) bad solenoid on the reversing valve

It will take an experienced technician to isolate the true cause
 
  #7  
Old 08-09-12, 11:36 AM
S
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,213
Received 1,287 Upvotes on 1,225 Posts
Welcome to the forums, alex - this question was more than two years old
 
  #8  
Old 08-09-12, 04:08 PM
HVAC RETIRED's Avatar
Member
Join Date: May 2008
Location: Wisconsin USA
Posts: 664
Upvotes: 0
Received 0 Upvotes on 0 Posts
He will probably never respond; but what is he doing with two condensers & one is 5-Ton.

Doubt there was enough air flow through the indoor coil & with a piston metering device liquid would be flooding back to the compressor taking out the valves...
 
  #9  
Old 08-09-12, 06:43 PM
E
Member
Join Date: Feb 2010
Location: usa
Posts: 564
Upvotes: 0
Received 0 Upvotes on 0 Posts
Two years old. Lol Thats funny. Also, dont mention anything about pressures or the moderators will be mad.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: