I have a Trane XE1200 1.5 ton heat pump system in my bonus
room that is my office. I am a pretty good DIY'r with some
history of commercial refrigeration in the 60's. I'll
probably get flamed but, I am tired of paying for service
calls with no results. This is my first heat pump.
A few days ago, it started using the heat strips constantly
where it seldom had ever used the strips and the air handler
runs constantly to keep up. OD temps in the 40's which
should be easy for it. All of the lines inside the unit
felt cool at about equal ambient temp. I pulled the
diagrams and checked the pressures and found both pressures
equal about where they should be for static ambient temps
with R22. The thermostat is calling for heat and the
contactor to the compressor is closed.
I checked again yesterday with temps in the upper 60's in
cool mode. Found the same - thermostat calling for cooling
and the compressor contactor closed with voltage to the
compressor feeds. Pressures are equal around 135psig.
Could not detect compressor running. (I don't hear well)
Voltage from contactor to compressor at 127 volts phase to
ground and 248 volts phase to phase which tells me the
compressor should be running. Checked for continuity in
compressor with feeds disconnected from contactor and found
both legs at infinity. The pressure sensor on the
compressor is closed. If I am reading all of this
correctly, the compressor is dead.
The reason I am asking is that the unit was not cooling well
in the fall. I had the service folks who installed the unit
when we built on 2000 out several times to check it. Even
though I was seeing what I believed to be low pressures,
they informed me this was OK. When I first started having
cooling problems, I was getting pressures like 150/82 on a
90 deg day with the unit running constantly. I have already
spent over $500 trying to get this resolved with the service
folks and the only thing they have done is test and add
refrigerant. The pressure have never increased above about
180 on the high side although the low side was about 125 the
last time I know the compressor was running while being
checked. This is an R22 system. I think the compressor has
been limping for some time. Am I missing something or is
it time to replace at least the compressor? Is a 6 year old
system even worth a compressor when install labor is
Any ideas or pointers greatly appreciated.
Obviously, the compressor should be running, and obviously something is
And we can't hear it here either. Did you test for the other indication that
would verify that it is running? You know, the one that doesn't involve
getting the gauges out, and works well regardless of the ambient noise
level. That measurement would answer the larger question, also.
You have a 3 phase compressor in a resi. application? Or, did you really
mean you measured line to ground?
The pressures, or the fact that you don't think the unit is cooling well?
Assuming the compressor is bad, it may or may not be under warranty. This
also depends on whether the tech. took notes on the fact that you've been
screwing with it. You will pay to have it replaced. The information that you
have provided regarding your tests does not definitively lead me to believe
that there's an issue with the compressor.
Stop screwing with it, and try a different tech. if you don't like the one
that's been coming out. Also... and this is REAL important. STOP telling
people - especially HVAC techs - that you've been releasing refrigerant to
the atmosphere. That itty bitty amount that leaks out when you take your 35
year old gauge set off is plenty to get you nailed by the EPA if you piss
off the wrong person.
On Sat, 25 Nov 2006 12:23:44 -0500, "Mo Hoaner"
Thanks for your response.
I was afraid of that. I may try to negotiate with the
service folks who have already not done me any good at
If you mean whether I tried placing my hand on it when it
should be running - yes - and felt absolutely nothing other
than a dead compressor. I also used my clamp-on amp meter
on the feeds and got no reading. The lines are all cool.
It is a single phase 230 volt unit. I have 127 on each leg
to ground and 248 across the legs on the compressor feeds on
the compressor side of the contactor.
The unit has never had a problem heating or cooling this
space. When it became obvious that it could not maintain
the ID temp of the roon at less than 90 on an 80 degree
space that it had neve had a problem maintaining 72 on
similar days, it did not appear to be performing well. I
used my guages and checked it finding what appeared to be
low pressures for the conditions and call the service folks.
They said it was fine and only need a bit of refrigerant. I
shrgged it off while the warranty expired. It got worse.
It was well within the 5 yr warranty when the tech came.
It is now out of warranty and out of my pocket. The
installers tech was the first to ever screw with it after
installation. It was built in 7/2000. Unless Trane has
extended their warranty without notice, it is all my nickel.
I would be more than happy for them to participate. I was
under the misinformed impression that Trane was the best and
should be good for a considerably longer time. I had to
have the Trane LPG furnace on the main level replaced a
couple of years ago. In this area, my prior heating/cooling
units have gone 12-15 years with no problem other than
Thanks, I'll only screw around with it if they experts I
hire can't help. I would have though the folks who
installed the systems during construction would have been a
good choice for maintenance. I appear to have been wrong at
Let's assume it is toast for the moment - or, at least, I
think it is. Do you have a recommendation. My thoughts now
are to go with a Lennox OD unit of similar specs since this
one seemed to work well untill it didn't. I am not inclined
to replace the air handler as it is in the attic and would
require some structure or roof to be cut out to replace. I
am sure as hell not in a mood to cut thru the roof.
Why go with a lesser quality piece of ...(Lennox) equipment??.... for a lot
less than a new system, you should be able to get the compressor replaced.
Just find a *COMPETENT* tech to do it.....and this doesn't necessarely mean
it has to be a Trane dealer.
If the outside unit is replaced, then the inside unit needs to be replaced
also so they are matched and will work as they are supposed to, and you
won't have any warranty issues if the installer decides to take a powder.
If you have to cut a hole in the roof to get the air handler in or out, then
it sure as hell doesn't comply with code and *NO* inspector will sign off on
The units I spec'd for my homes and offices before this were
all Lennox with zero problems for more than 30 years. I
decided to go with what was reputedly the Cadillac of the
business this time and have had a bit of bad luck with both
units. There is only one Trane dealer in this area and I am
not inclined to call upon him based on my lack of joy in
getting this problem resolved and being jockeyed past the
warranty expiration for the compressor unit after it first
exhibited signs of failure.
From what I have been able to learn from limited reading,
bad pressures in a heat pump are basically caused the same
way as in straight a/c systems. The biggest twist in the
pump system is the reversing valve. I can see how a leaking
or stuck valve can result in low pressure and may (will)
also eventually lead to compressor failure. This one
appears to be electrically dead at this time. I believe the
key to this has been in the pressures and temperatures
during operation. If I do replace the compressor, how can I
be sure the reversing valve was not reponsible and cost me
more after the compressor is replaced to get it back online
operating properly?? If I read this right, there is no way
of testing the reversing valve other than the solenoid short
of putting it back to work to see what happens - is this
correct? I feel I have been given the mushroom treatment
by the installer now for a year and a half. I do greatly
appreciate any info I can get to help in making an
intelligent decision on how best and who to get in repair or
replacement of the unit. I hate someone trying piss in my
face and tell me it's raining!!
This is not a job subject to inspection unless I am
re-roofing the house. Nevertheless, the lineset and AH are
not going to get replaced quite simply because of the
structural work that would undoubtedly run into the
thousands to pull it off in this installation. That part of
the repair is not an option even if it works at less than
optimum. If I have to do that, I will scrap the heat pump
and install an attic furnace plus A/C unit. At this point,
I am not impressed with the life expectancy of heat pumps or
the availablility of competent repairmen in this area.
On Sat, 25 Nov 2006 17:17:15 -0500, "daytona°"
I have a decent Fluke meter and can get hands on whatever I
need to test or repair if I have to. My problem here has
been the lack of difinitive values that I may look for. For
that reason, I have only looked at the basics as I recalled
from my days with the chiller units.
Do an ohms test between the Start, Run and Common wires in the control
box...this way you do not have to get into the compressor. Some compressors
are a little difficult to get to...other are very easy.
The test is to see if the windings are open....I don't want to get into
shunted and weak. Shorted winding would blow the breaker or pop the fuse
quickly. Could be a burnt off terminal at the compressor, could a faulty
internal overload ...who knows. It's hard to diagnose with out being there
On Sat, 25 Nov 2006 17:17:15 -0500, "daytona°"
Just wanted to ask if by chance you are in the Daytona area
and been there for a while. I had a friend there in the
HVAC business for years. He disappeared after the divorce
to some black hole in MA.
I have wondered about the start cap on the unit but, have no
way to test. I suppose I could just put one in since thay
are relatively cheap. The condenser fan does runs as it
should when the contactor closes. I cannot detect current
to the compressor even though it has line voltage on each
feed. There is a relay to the caps that is closing as it
should. This is a Trane TWP018C100A3. I found the
schematics inside the unit. I have seen a couple of
compressor with bad start caps but, they always had a thump
when energized and tripped the breaker after a few seconds.
I am not getting that here - ammeter reads zilch when
powered. Is there a simple way to test the caps short of
burning a good screwdriver?
With the compressor cold.... ie not tried to start in a while... check
the resistance between the S and C.. and the R and C on the compressor.
Do this with the unit disconnect OFF and you'll have to pull the little
'flag' connectors off their various terminals.
R and C is going to be between the two phases of your 240 circuit on the
contactor load side. Again, you'll have to pull the connectors off
because otherwise you'll read other stuff.
S and C is going to be between one phase on the contactor load side and
the capacitor lead from the start relay going to the compressor S terminal.
You should get continuity between C AND both S/R.
If you don't... an internal overload (or the compressor motor) has
opened up and it'll never run again.
I don't know what the labor rates are in your area... but I KNOW I'd
consider a compressor changeout on one that young. I'm not an HVAC guy
but a pretty competent electrician that's changed several. It's not a
DIY job, though... unless you wanna spend some serious money on tools
Chances are.. there is something else wrong here, though. Get a good
tech to take a look-see. You don't have to replace the indoor unit...
but replacing the coil to match the condenser is always a good idea if
you go that route.
Boy... I'll bet I've made some folks mad here... but you seem to have a
good grip on things.
Thanks, Jake. I am going to print this and give it a
look/see tommorrow. It may take me a while to learn what I
need to know on this but, I want to know WTH is wrong with
it that the installers were unable to detect. They were
just here a few weeks back for not cooling and gave it a
clean bill of health. If the compressor has to be replaced,
it won't be by me. I just want to make sure it is the
compressor before I pull the trigger on a problem that could
have been more reasonably repaired. I just got an e-mail
from a shop about 100 miles away that has an exact model
complete Trane outdoor unit for $695 loaded on my truck. He
said he has a couple for a job that he ordered for a
contract that fell thru a few years back and would still
have full warranty since they had never been installed. He
won't install for me because of the distance. I have no
idea what a tech would charge to hookup and charge with no
warranty responsibility. They may want to charge as it they
had installed a complete system from their supplier in which
case I will brush up my brazing skills that haven't been
used in about 15 years. So far they are suggesting a
compressor replacement is likely to be over $1200 with no
guarantee that it is all that will be needed. I have no
idea at the moment if those prices are real world right now.
It may be a decent price for all I know.
A couple of thoughts. If the compressor did burn out, it's very
possible that the system is full of acids, and other corrosive
chemicals. I'm not sure if acid neutralizer filter driers are still
made, but it's a good idea to ask for one.
I usually figure three hours for compressor change for refrigeration
equipment. Might be more for an outdoor Trane unit. But to change the
entire outdoor unit should be three hours or so. Including the freon
recovery. Figure five or six pounds of new freon into the price.
695 for the unit on the back of your truck sounds fair. 1200 for the
compressor, installed, sounds reasonable. But given those two prices,
I'd call around and try to find a tech to install the condensing unit.
May as well get the new contactors, reversing valve, and so on.
Christopher A. Young
You can\'t shout down a troll.
"I cannot detect" very often means that the writer does not own
the equipment necessary so that he can detect the value. People who
have the equipment often write "I read zero...."
Reading farther, it appears you have an ammeter, and can use it.
Which is it? Do you lack the equipment, or are you reading zero
current to the compessor while it's getting 220 volts applied?
Christopher A. Young
You can\'t shout down a troll.
On Sun, 26 Nov 2006 12:32:52 GMT, "Stormin Mormon"
I have the meters. The only thing I do not have are the
digital temp sensors which are not much good in what appears
to be a non-functioning unit. I could not detect meant that
I could not hear or feel the compressor running nor was it
warm as I would expect. I used my ammeter on the feeds to
the compressor and found a "0" reading. I went further and
checked the voltages by the diagram in the unit. I found
what apears to me to be correct voltages from the thermostat
to the controls and correct line voltages. I found the
compressor contactor closed when the stat calls for duty and
open otherwise. There is 127volts on the compressor side of
the contactor of both feeds to ground and 248 volts across
the feeds as it should be. The compressor sensor is
"closed" according to my meter. I believe this
qualification has to be met for the contactor to close
providing voltage on the compressor side of the contactor as
it controls power to the contactor solenoid preventing it
from closing if the sensor is open.
Another thing I have noticed is the green LED on the defrost
control board is flashing 3 times which can indicate any one
of several things but, the docs I have are a clear as muddy
water on how you would proceed from there. One of those
faults is low refrigerant charge. I should be able to rule
that out in the case of a no start/no run compressor if the
compressor has voltage and the sensor is closed and, I have
what appears to be at or above correct static pressure for
the ambient temp which should indicate at least a partial
charge. The docs indicate a single flash to be normal. I
am a bit confused as to why there would be voltage to the
compressor if a hard fault has been detected since the
compressor sensor is fed from this board. I believe the
board uses this connection to determine whether there is a
charge in the system. Again, I believe a lack of voltage
here would prevent the contactor from closing. Is it
possible that the closed compressor sensor is the indication
of a low charge instead of an open sensor? If this is the
case, I still would not understand why there is line voltage
to the compressor.
Your help and comments are greatly appreciated.
I hate to say it but your posts sound more and more like you are going
to perform the do-it-yourself route. Fortunately, Im in an area where
the hvac guys are a dime a dozen. Unfortunately, there are only a
couple that know what they are doing.
Just so you know, a properly sized and installed heat pump system will
last a VERY long time. A HUGE part of that is finding a company that
knows how to pull a proper vacuum. I am 100% convinced that a proper
vacuum leads to a long compressor life.
Short of all that being said, you need to have your system check and
or replaced by someone that knows what they are doing..............not
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