Finding TXV problems?

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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? Bubba
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Bubba wrote:

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.
--
Zyp



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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 same problem. Bubba
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wrote:

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.
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wrote:

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. :-) Bubba
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wrote:

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.
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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
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Yes, it has a LPS It also has a HPS, so *why* isn't it opening up first???

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lp13-30 wrote:

I have had a few in the last several years where the IPO did open after start up. Replacing the compressor cleared it up. [Although not a new unit.] Could it be a weak IPO spring?
--
Zyp



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Tony was in the factory the day it was made and substituted a R22 relief for a R410 relief. LMAO
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wrote:

It is a straight Air unit only. Bubba
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I know that none of you will agree with me however you have choice replace compressor or dump 410 and charge unit with 22 good lock tony
wrote:

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new jersey wrote:

What?
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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.
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Gary wrote:

Some Mfg's are using Parker valves which appear small. Since the service valves on the units are Parker / Hannifin - it only makes sense they'd use Parker driers and TXV's ......
--
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I've saw some units with one Parker sv and one Sporlan sv... now what? :-)
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Is this an N or T4A460?
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wrote:

N4A360AKB200 Bubba
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Oh, its a 13 SEER unit...
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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 expansion valve. 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? :-) Bubba
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