Has anyone been seeing new TXV problems?
Ive recently installed a Tempstar 5 ton 14 SEER condenser with an
Aspen TXV coil. (Sorry, the Tempstar matching coil had NO WAY fo
fitting in that space.) Ran fine about a month. Customer called
saying it wasnt cooling and was making a ton of noise outside. I get
there turned it on and watched it run perfectly and flawlessly for
about 1/2 hr. Subcooling was perfect. Went to the truck to do some
paperwork and customer came out and told me the noise started again.
Sure enough the Internal relief valve opened up in the compressor.
Shut the unit off and back on and it ran for almost 2 weeks fine
again. Same problem yesterday. Gotta change out the TXV this week
which is evidentially closing intermittently.
Had a Trane dealer close to me tell me the same exact scenario about a
week ago of a new Trane system he installed.
Anyone else found this lately?
Check the mesh screen in the liquid line connection at the valve. Also,
install a new liquid filter drier in the liquid line before the valve. If
the valves thermal diaphram is failing, it may be a "bad" liquid charge on
the thermal bulb. A failing thermal bulb will close the valve.
Thanks for the info Zyp but these are the factory installed cheap
expansion valves. You know, the ones those Tiwanese or Koreans or
whoever is shipping this cheap junk. No serviceable screens, parts or
adjustments. The bulb charge is not bad as that would shut the valve
and keep it shut. This is a very intermittent problem. It has occured
twice in about a 2 to 3 week period.
Im thinking there may be a lot of this showing up shortly.
As always, I always install a new drier at the indoor coil.
Hoping I find others that are running into this problem.
I just dont want to change the valve with another valve that has the
Is it possible that the bulb is not attached correctly or if its R-22, I
would also be wondering if there is some moisture in the system, or non
condensibles that make it *seem* like the valve is closing.
Sorry about that. This is Strictly R-410a systems. NO R-22. Bulb is in
the 10 oclock position on a horizontal run and insulated. No moisture
unless the new drier and 400 microns I pulled on it and held with my
JB Vac pump and digital guage lied to me. :-)
Sorry, my bad.... had to ask tho... sounds like wither a bad valve or
blocked screen. Is it a heat pump?? or straight a/c?? If its a heat pump,
when it does its thing, switch to heat mode to see if it clears when you go
back to cooling. That might help tell you if there is trash in the line or
its a bad valve. Just cause you did all the right things right when you
installed it, that doesn't mean that all the right things were done right at
the factory. A piece of trash in the line will ruin your day.
I am kinda surprised that the condenser coil and liquid line would not
hold the system charge and just pump down until the LPCO opens (if it
has one), rather than driving the head up enough to open the IPR. Did
you have the guages on the unit when this happened? I've never seen an
IPR open on 410A yet. Where does it open? I would assume about 550- 600
more or less. I've seen them weak on 22 units and open at about 275, but
these were on old units that had run with dirty condersers for years.
Probably not likely to have a weak one on a new unit, but I suppose
anything is possible. BTW, I agree 100% about the crappy valves they
have now. A couple of years ago I got tired of them and bought a Sporlan
at about $70 for a coil installation, and it was worse then the Amana
valve I took off. Larry
I just had one this week go out on an American Standard 410A system a year &
a half old. I don't know what brand TXV but it was smaller than usual & it
wasn't an Alco or Sporlan. They didn't put a dryer in the installation.
I asked one of the Trane guys about it & he told me they don't put dryers
in because they come pre-installed in the condenser.
Well, at this point Im open to ideas but I think just the opposite
would be true. Remember, Im not closing the high pressure service
valve and reading pressure from my gauge on the line set side of the
unit (which would drop as the compressor continued to pump.)
Whats happening is if the TXV is truely closing completly and I had my
high side gauge on the high side service valve, the compressor would
be sucking all the refrigerant pressure back to the unit via the
suction line and then trying to pump it back out which it could do.
BUT then it can only travel out the liquid line until it reaches the
Thus, If I were able to catch it actually happening but before the
internal relief valve opens, I would be seeing very high pressures at
my high side gauge on the service valve.
High enough in fact to open the internal relief valve.
Make sense or did I just redesign the law of physics? :-)
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