CaptHook
04-25-2012, 09:46 PM
Today I was dispatched to a PTU ~ Precision Tune up on central air system.
I arrived to a tennant, whom stated the landlord called us out to "tune up" the system.
Performed interior checks as normal. Condensate, blower, filter etc.. Temp split and equip particulars:
-Goodman GF furnace 3 years old
~Fixed orfice
~Changed 20x25 "plugged filter"
-Coil clean, (inspected through limit with camera)
CFM (measured with Vaneometer) 1500 Which matched the 4 ton coil specs
-Wet entering 57
-Dry entering 71
-LAT 50
-Temp split 21
-Fixed orfice
so far so good right. :)
Went outdoors, to find.. :)
-Goodman 4 ton cond 410a unit 3 years old
-2 Pieces of electrical tape loosly around suction and liquid line
-Suction line Schrader cap in dirt by unit
-A pocket thermometer stuck to the side of the disconnect, apparently left by a tech.
-3 or more screws missing from electrical compartment and cond fan top.
-The first companies sticker, so large, the second company couldn't put theirs on it to cover it up, The third companies sticker trying to cover the second companies sticker, which was partially pealed off.
Now thinking to self... "Self, your are not the first one here,, lol"
I asked the tennant if they knew of a service issue,
He started talking.
He stated a company came out to do maintenance the first year the condo was purchased, he was there for a few hours, on the phone alot.
He came in to tell him, there is a problem with the unit, call the installing company to return to fix it under warranty.
He then told me he "thinks" the landlord called the installing company, as another company came out a few days later.
The service man was outside for some time, another truck pulled up, another man joined him outside by the condenser, they brought refrigerant in and said it was low on refrigerant, charged the unit and left.
The next year, the landlord called in a different company,, "advertising special" to tune the unit up. Not us (yet)
The tennant told me, he was there for approx an hour, also brought refrigerant in, charged it and said it was low also.
Now the present, He said you are the 4th company out to "tune up" the unit.
I knew something was up, and took the challenge. ..LOL
Hooked the guages up and wala,, Head pressure bouncing from 250# to sometimes over 400# within seconds. Semi stable,, suction of 123#
I used my testo 570 this time, have digicools, but like my 4 way manifold on the Testo's.. And the batteries were good in them, lol.
When numbers settled the best they could, this is what I had ~
Suction
~ 123# Converted to 42.3 * 410a
SLT 46.8
Superheat 3.9
~231 to "all over the place" lol converted to 77.9
LLT 59.3
Sub C 19 to sometimes bouncing up to 30 +
ODA = 69
Compressor amps 14 rated at 16 (more than 80 Percent)
Normally stable pres would tell me with these numbers , they have flooded the unit.
The head bouncing concerned me, under normal flooded circumstances, i do not normally see the bouncing head so much and heavy.
First check, not normal to find in my area, but U can follow me i bet.
~Disable compressor..
~ Thermister on discharge line 69 deg
~Thermister on liquid line 69.something
~ODA on Air entering Cond,, 69 deg
When they were all about 69, givin prob 10 min
My LL guage , press was 217# Converted to 75 deg
Hence 75 much > 69 Deemed non condensables
At this time it was a starting to point to work, however even with non concensables, i truely dont remember such eratic head pressure, In less than a second, the press would be from 230's to nearly 400 #
Quoted the customer to recover, evacuate, inspect orfice, recharge.
After an hour or so explaining rocket science, had the approval.
Results ~
Recovered 10# refrig **System factory charge 7# 12 oz
Took LL apart at evap to remove orfice,,, was caught in a thought,, "does that look like it's in right" Nope,, in backwards.
Cleaned it, purged the system with nitrogen.
Reinstalled orfice in correct direction
Evac to 500 microns, wait 20 min, hold for another 10,, all good
Recharge 7# 12 oz with nominal 15 ft lineset,, should be good.
Fired up,, Stable suction, Stable discharge,, 13 SH 11 SC
So the job went well, but what caused it to start,, lol
To add to the confusion, the tennant inquired, "Do you all paint your tanks different colors?"
LOl... No,, it is definition of refrigerant type, he was sure, either second company or third, used a "green" can..
I think the Orfice was the main problem, the new blend of refrigerant one of the tech's created, was what caused my reading of non condensables, and one or the other flooded the system.
Customers happy, system is working well..
Thought as a newbie here, would share my exp, as all of you I bet have had, when you enter a "logistical nightmare" of service companies trying to solve the problem, mixed with a customer, hunting for the best tune up price.
Hope you all have a great day night, let me know what you think of my procedures, always love learning others tricks and tips, one can never know everything. I was very curious if 410 units, since i have been outside service for a couple of years, used a check-valve in the condenser circuit as well. I was concerned that could be causing the bouncing.
Matt
I arrived to a tennant, whom stated the landlord called us out to "tune up" the system.
Performed interior checks as normal. Condensate, blower, filter etc.. Temp split and equip particulars:
-Goodman GF furnace 3 years old
~Fixed orfice
~Changed 20x25 "plugged filter"
-Coil clean, (inspected through limit with camera)
CFM (measured with Vaneometer) 1500 Which matched the 4 ton coil specs
-Wet entering 57
-Dry entering 71
-LAT 50
-Temp split 21
-Fixed orfice
so far so good right. :)
Went outdoors, to find.. :)
-Goodman 4 ton cond 410a unit 3 years old
-2 Pieces of electrical tape loosly around suction and liquid line
-Suction line Schrader cap in dirt by unit
-A pocket thermometer stuck to the side of the disconnect, apparently left by a tech.
-3 or more screws missing from electrical compartment and cond fan top.
-The first companies sticker, so large, the second company couldn't put theirs on it to cover it up, The third companies sticker trying to cover the second companies sticker, which was partially pealed off.
Now thinking to self... "Self, your are not the first one here,, lol"
I asked the tennant if they knew of a service issue,
He started talking.
He stated a company came out to do maintenance the first year the condo was purchased, he was there for a few hours, on the phone alot.
He came in to tell him, there is a problem with the unit, call the installing company to return to fix it under warranty.
He then told me he "thinks" the landlord called the installing company, as another company came out a few days later.
The service man was outside for some time, another truck pulled up, another man joined him outside by the condenser, they brought refrigerant in and said it was low on refrigerant, charged the unit and left.
The next year, the landlord called in a different company,, "advertising special" to tune the unit up. Not us (yet)
The tennant told me, he was there for approx an hour, also brought refrigerant in, charged it and said it was low also.
Now the present, He said you are the 4th company out to "tune up" the unit.
I knew something was up, and took the challenge. ..LOL
Hooked the guages up and wala,, Head pressure bouncing from 250# to sometimes over 400# within seconds. Semi stable,, suction of 123#
I used my testo 570 this time, have digicools, but like my 4 way manifold on the Testo's.. And the batteries were good in them, lol.
When numbers settled the best they could, this is what I had ~
Suction
~ 123# Converted to 42.3 * 410a
SLT 46.8
Superheat 3.9
~231 to "all over the place" lol converted to 77.9
LLT 59.3
Sub C 19 to sometimes bouncing up to 30 +
ODA = 69
Compressor amps 14 rated at 16 (more than 80 Percent)
Normally stable pres would tell me with these numbers , they have flooded the unit.
The head bouncing concerned me, under normal flooded circumstances, i do not normally see the bouncing head so much and heavy.
First check, not normal to find in my area, but U can follow me i bet.
~Disable compressor..
~ Thermister on discharge line 69 deg
~Thermister on liquid line 69.something
~ODA on Air entering Cond,, 69 deg
When they were all about 69, givin prob 10 min
My LL guage , press was 217# Converted to 75 deg
Hence 75 much > 69 Deemed non condensables
At this time it was a starting to point to work, however even with non concensables, i truely dont remember such eratic head pressure, In less than a second, the press would be from 230's to nearly 400 #
Quoted the customer to recover, evacuate, inspect orfice, recharge.
After an hour or so explaining rocket science, had the approval.
Results ~
Recovered 10# refrig **System factory charge 7# 12 oz
Took LL apart at evap to remove orfice,,, was caught in a thought,, "does that look like it's in right" Nope,, in backwards.
Cleaned it, purged the system with nitrogen.
Reinstalled orfice in correct direction
Evac to 500 microns, wait 20 min, hold for another 10,, all good
Recharge 7# 12 oz with nominal 15 ft lineset,, should be good.
Fired up,, Stable suction, Stable discharge,, 13 SH 11 SC
So the job went well, but what caused it to start,, lol
To add to the confusion, the tennant inquired, "Do you all paint your tanks different colors?"
LOl... No,, it is definition of refrigerant type, he was sure, either second company or third, used a "green" can..
I think the Orfice was the main problem, the new blend of refrigerant one of the tech's created, was what caused my reading of non condensables, and one or the other flooded the system.
Customers happy, system is working well..
Thought as a newbie here, would share my exp, as all of you I bet have had, when you enter a "logistical nightmare" of service companies trying to solve the problem, mixed with a customer, hunting for the best tune up price.
Hope you all have a great day night, let me know what you think of my procedures, always love learning others tricks and tips, one can never know everything. I was very curious if 410 units, since i have been outside service for a couple of years, used a check-valve in the condenser circuit as well. I was concerned that could be causing the bouncing.
Matt