Finding TXV problems?

[KJPRO]

The pressure has to be high in order for the IRV to open.

[Gary]

I understand that but things don't always work exactly to specs & still have no effect on normal operation. Say the IRV was designed to open at

600 psi & the HPS to 550. It would not seem unreasonable for the IRV to trip first. It would only have to be 10 % off between the two of them. The other thing is with an IRV the back pressure may have a role in its opening to a small degree. A valve might open at 500 with 25 on the low side but not till 600 with 200 on the low side. I only guess this because like I said before I've had a lot of IRV's open on pump down before the HPS. The amount of refrigerant has something to do with it also because if I recover about three lbs. the same unit that trips the IRV will usually pump down with no problem.

[Zyp]

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]

What?

[Zyp]

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 ......

[Zyp]

What?

[Zyp]

Didn't he [new jersey "tony"] say to replace the R410 with R22 earlier? ROFL

[KJPRO]

I've saw some units with one Parker sv and one Sporlan sv... now what? :-)

[KJPRO]

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

[Bubba]

Agreed. I havent pumped it down yet.

Slightly larger yes, but remember.......Tempstar uses 7mm tubing instead of the normal 8 or whatever. This allows for a 40 something percent smaller amount of actual volume in the lines (straight from Tempstar info).

It isnt. Its charged correctly. Remember the smaller tubing though, above.

I didnt check superheat and I did add refrigerant to the system when it was installed because the lineset was longer than 15 ft. Somewhere around 35 if I remember correctly. I did measure it at the time so I could get an accurate number to add to the system.

See above

I have to check again but I dont believe this unit has a LP switch and I know for certain it does not have a HP switch.

?? Im just going to have to agree to disagree with you on that one.

Again, it has no HP switch.

We did the ductwork and HVAC on this home when it was new (about 18 yrs ago) and did a Manual J and manual D on it.

Yes it does. Externally equalized too.

Nope, just the problem it is exhibiting now.

I know you arent second guessing me and I appreciate the info. You did forget though that if Im going to dump the charge and add new that I would of course replace the filter drier. :-) I get no bouncing of the gauge pressures while the unit is running so I dont suspect any non condensables and as I always preach, this one got an evacuation to below 500 microns with my JB pump and digital vac gauge.

It still has only done this twice in about 3 wks now. Very intermittent and correcting it temporarily is as simple as turning it off and back on. I suspect the TXV or a weak IPS in the compressor but since I cant isolate it Id replace both at the same time and hope I dont receive another bad compressor or TXV. Im still waiting for some answers from Tech support at ICP since they seem to be acknowledging that they are having some sort of small isolated instances of this problem. Hopefully I will get an answer soon before this customer "fries my arse". :-) Bubba

[KJPRO]

He was indeed...

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[KJPRO]

Wouldn't make any difference, as the refrigerant charge is less because of the smaller tubing. It's a ratio that isn't really going to change.

No biggie... .6 oz times 20 feet = 12 oz extra.

The N4A360 should definately have a high and low pressure switches. page 17 numbers 17 & 19

It should have both a hi and lo pressure switch.

Why, you're not opening the system to atmospheric pressure. There's really no need to replace it unless you just want to. Now, if you are going to open the system up for repair... yes change it, no questions asked.

I don't think you'll have a problem with the client... she already requests you because she trusts you. It's just simply something that's odd and you're going to make it right for her when you locate the problem. It's not like you're not trying. :-)

[Bubba]

:-P I already changed the stat. That didnt work so I changed it again. Then someone told me it takes up to 4 stat changes before you get one that works so I changed it 4 times. It still doesnt work. Should I change it again? :-)

Nope. Not true. This came from the TSA at my local distributor. Im very good friends with him and get a lot of info Im probably not supposed to have sometimes. Like, I know exactly how many units have exhibited this same problem within about a 100 mile radius of here. The most recent being another one yesterday. Anyways........ With shorter line sets these Tempstars will NOT hold the entire charge and will allow the internal relief to open. I dont know if I can get that for you in writing but I will if someone wants it.

Bingo

If ONLY I could catch it in the actual act. :-)

There is NO high pressure switch factory installed or field installed on this unit. I have to look at the unit again to tell you whether or not it has a LP switch installed.

That might be ok on larger commercial stuff by soooooo not worth the effort on resi crap.

Thats a thought but right now Im pretty confident its not the bypass.

Not to worry though. I will figure out the problem and I'll be happy to report back with my findings. Bubba

[Bubba]

hehe. Somebody forgot to read the fine print. If you will look on page

3 of the link you sent you will see LPS DTS HPS, LLS switches ALL have an asterisk by them. Then look at the bottom of the Legend on that same page and you will see " * MAY BE FACTORY INSTALLED" Obviously that means "May Not Be Installed to because I dont have any of them that I know of but I will take a pic of it when I go back and post it for you. :-) Bubba

[lp13-30]

Interesting! I'd have thought the condenser would hold the entire charge and pump down easily. I guess the IPR would be easy enough to check. Disconnect the fan motor or block the condenser and see when it opens. One more question-- does that unit have a 2 speed fan motor? We have had problems with Amana and Goodman (ain't that a shock). The thermostat that switches the motor speeds acts up somehow. The only one I have had personally was DOA on a brand new unit I installed. I just bypassed the POS and hooked the motor to high speed. If the motor was cutting off on overload it would stay off long enough for the compressor to overheat and cut out of IOL also, but if that thermostat is erratic, maybe the fan can cut out just long enough to cause the IPR to open. Remember-- it is usually the thermostat. Larry

[KJPRO]

I like pointing out his lack of knowledge... especially since he brags about being smarter than HVAC techs. :-)

[KJPRO]

Yeah, I'm just the kinda of guy that would like to see just that, if you can get it.

[KJPRO]

The N series (which Bubba is dealing with) is a single speed motor, while the premium H series has the two speed motor.

[KJPRO]

Yeah, I saw that too... They list that on almost everyone of their tech sheets... like the H2A3, H2H3, H4A3 and H4H3. However, *all* of these come with both switches... this is the Premium line as you probably already know. The ad sheets say the H includes both, while the N says nothing. EPMS shows them, go figure. I don't mess with the N series... just don't care for them. I didn't think ICP manufactured a R-410a unit without a HPS... guess they must have found a way to save money.

[Gary]

The joke around here is anyone who knocks Goodman has never installed ICP. They come up with problems that defy the laws of refrigeration. I've installed some of their units that have lasted twenty years but also some that have gone where no unit has gone before. My favorite is the "Green Slime". For those who never heard of it, it's some chemical reaction in the oil that formed green slime & clogged up the entire system. The unit not pumping down doesn't surprise me at all. If you told me pumping down the unit made the garage door open with an ICP unit it wouldn't be a big surprise. So if there was a faulty TXV in another manufacturers coil be happy your truck is still running.