Any Rheem guys out there?

[Gary]

I just came back from my neighbors unit, its a 14 SEER Rheem R22 split HP. We walk our dogs together so he asked me if I could look at it tomorrow. He said it wasn't cooling when he got home yesterday so he shut off all night. I went & get my tools & checked it for him today. Water had been coming out of his secondary overflow at the eave so I figured it was probably the attic float switch. I used a wet vac on the secondary & primary & the system started up O.K. Here's where things get screwy. I checked the pressures & the system has fixed 25-30 degree superheat(TXV) on the plate. According to the chart the head pressures were right on the money. SP - 55 psi HP - 225 psi SH - 27 deg. SC - 20 deg.

86 DB outside temp 80 DB inside temp

Temp across indoor coil 12 deg.

I originally thought the charge was low but I always check the unit specs when available first. Any other unit I would say would have a restriction with high SH & SC but I've never seen a TXV that calls for such high SH. It doesn't even have a subcooling reference at all. Its pouring water out of the drain so its obviously doing some dehumidifying. I'm going back to check in the morning when I'll actually feel like working but curious if any one familiar with Rheem has ever run into this funky TXV 25-30 deg. SH spec. on a residential unit.

[Noon-Air]

I need model and serial numbers.

Something is not right.. need model and serial numbers.

What are the model numbers for the heat pump and the air handler? The coil model number would be good too.

As a rule, with Rheem stuff, you want 10 - 14 degrees of subcooling.

My first impression is that its overcharged....and there may be an airflow restriction to complicate matters, and until I know what the model numbers are, I really can't tell you much else.

[Zyp]

Superheat's too high for low air flow. I'm thinking the screen at the TXV is clogged or semi - clogged. Seems like the condenser's back up [high sub-cool] and the evaporator is dry [not enough refrigerant]. low performance [low TD on evap.] is also evidence that there's not enough refrigerant flow.

You should have a higher suction with the indoor temp. @ 80 deg., and a 10 -

14 deg superheat.

Check your TXV inlet screen.

[Gary]

Outside Model # RPNJ031JAZ I'll probably get the indoor model numbers tomorrow. I was in shorts & sandals & not about to go into the attic today. I just came back from walking my dog again & he said everything was working great. It's cold as ice in the house & it got to 90 degrees outside after I left.

I might try another set of gauges tommorrow just to be sure but it has specific charging instructions on the unit inside cover. They say that the TXV used for cooling is non adjustible with a fixed 25 to 30 degree SH. It doesn't have any subcooling specs but it gives specific head pressure readings under outside ambient conditions. The SH just doesn't make sense. My Suction line temp was 57 & air coming out was 68 which seems about right. According to what's written on the unit I'd need to have about

47 psi on the suction line to get a good temp drop across the coil. Most Rheems that I've worked on have a little higher than normal suction pressures because they run well over 400 cfm's per ton. Maybe this was one of Rheems experimental units. I can't find it listed in ARI at all.

[Gary]

The problem is the TXV is supposedly non adjustable fixed between 25-30 degrees. I've never heard of such a thing on a Heat Pump.

[Noon-Air]

ummm...no.

The correct TXV is non adjustable, and when properly installed, maintains

15 - 20 degree SH

Because its obsolete.

The RPNJ model was only made for about 5 years. It should be matched with an RBHK-21 air handler (with ECM blower motor), and RCHJ-36A1 Multiflex coil. According to the charging chart, at 80 degrees, your LLP should be right at

205psi with a 10 - 14 degree subcooling. Your SP is too low, your SH is too high... is there a kink in the LL anywhere?? or dirty TXV screen, or did somebody not properly install the TXV in the first place. When the TXV is installed on those, the piston is changed to .120 along with installing the TXV.(unless the coil/TXV were factory assembled). Just for grinns, when the heat pump was installed, did the installer put in a filter/frier?? or did the unit come with one internally?? I just had a thought(No, paul, it didn't hurt)... the problem with this system...is constant?? or does it come and go??

[Gary]

As far as I know he's never had a problem in 8 years living in the house. He says its working fine now too. I appreciate all the info. I'm sure if anything had to be field adjusted like the correct orfice it wasn't done. When I check piston sizes in systems that need to be field installed I'll find maybe one out of ten correct. Most guys around here just install a system with whatever it comes from the factory with. It's rare to even see a jumper on the defrost boards even changed. The only thing that concerns me is that I don't want to go tearing into the system just because it doesn't read the way I think it should. The owner has no complaints & the numbers pretty much match the specs written on the unit. Maybe I'll think clearer tomorrow.

[Stormin Mormon]

Water coming out the secondary drain is always a concern, to me. Makes me wonder, if the primary drain is clogged.

Since he had the unit turned off over night, it's possible the evaporator was frozen over. Not as likely with a TXV coil, though. High super heat may be from humidity removal.

Good idea to check the temperature of the liquid line leaving the condensor. I'm finding that most of the systems I am asked to service have dirty condensors. Many times, some condensor cleaning is all the system really needed. Please let us know what you find.

[Stormin Mormon]

Eight years? Did he have the coils cleaned, in that time?

Another idea. Many times, when I'm diagnosing, the amp draw is the number that sheds light on the matter. see how hard the compressor is working.

[KJPRO]

There's the ole "clean the coils and measure the amp draw" routine.

How about measuring the "current draw"?

[KJPRO]

No shit?

Really, post the facts that back this up... I won't be waiting long.

Time for a good ole cleaning Eh?

So you can parrot the results on the next HP thead?

[Gary]

Rheem Outdoor unit Model RPNJ031JAZ man. date 10/99 Air Handler Model RHBHB-21J11NFAA Coil model RCHJ-36A1G

Things look a little better today: Getting about a 14 degree drop.

75 db inside 85 db outside

S Pres 64 S Temp 59 H Pres 210 LL Temp 87

So I'm running about 23 deg. SH & 18 deg. SC I reread the charge plate & it definitely says: "system equipped with non adjustable fixed TXV's - 25 -30 degree superheat cooling & 10-15 deg. superheat heating" Also on the unit it specs 10 -15 deg. liqid line temp above outdoor ambient. Since I'm only 2 degrees above that suggests an overcharge.

I did notice a 1/4" liquid line set which was smaller than both indoor & outdoor line set connections. So it should be 3/8" line set or at least

5/16". Plus its probably over 50 ft. line sets. That might account for the higher than normal SC.

Well the owner is happy & it's cooling the house fine so I'm not touching it for now. I'll still keep researching.

[Noon-Air]

1/4 inch LL?? Is this the second system since the house was built?? If it is, was the first system a Lennox?? That 1/4 inch LL will make for a high SC, and high LLP. BTW, your correct...over 50ft does require a 3/8LL. the RBHB air handler is not the correct one for that heat pump(at least not for it to be 14SEER), the one needed for that heat pump is either an RBHJ or RBHK with the ECM blower motor....the coil is ok, it was added as the air handler didn't come with a coil installed...

If your neighbor wants you to replace his 2 1/2 ton system in the future, try this out for size... RPNL-030JEZ heat pump with an RHLL-HW3617JA air handler. ARI rates it as

15SEER with 9.25HSPF. ARI REF# 823415

[Gary]

The original system was an old GE which probably had 1/4" LL but when this system was put in I would've thought they ran all new copper. They moved the condenser to the other side of the house & ran the copper down a closet from the attic to the crawl space. Anything's possible though, they could have saved the old copper & reused it.

I'd be curious if you could find any specs on the TXV with that AH coil? I still can't figure out why it calls for 25 - 30 deg. SH on the condenser chart.

[Stormin Mormon]

Did the liquid line set loop several times, at the one end or the other? Some of the really early systems, they used the lineset as a metering device. Should not be the case, with the TXV coil. I think you're on to something, try a 3/8 liquid line.

When the guys on the list aren't calling me a F' hack, they may agree. Clean the condensor is rapidly becoming my favorite thing to do to a system.

Gary, I presume you cleaned the condensor? Even if it appears clean, it can still be running way under efficiency.

[Stormin Mormon]

Hmm. Was it Lummox, that did the LL metering device? It's been years, and I only saw one or two.

[Gary]

You're talking about the old Lennox that used its liquid lineset as a cap tube. That was for straight air only. Its not got that.

Maybe I'm lazy but I don't routinely clean the condenser unless I suspect it as a possible problem. There's nothing in my readings that suggest a dirty condenser as the problem.

[Noon-Air]

no tellin.... I got no idea about the specs on the TXV... I checked the archives and it doesn't give specifics. The training I recieved on Rheem systems with Multiflex coils says 10 - 14 degrees SC to ensure a solid column of liquid refrigerant to the expansion valve.

BTW.. a little more info on that system as its configured(this is what not having the correct air handler will do)....

12SEER, 10.8EER, COP 3.3, HSPF 6.95...not even close to the advertised 14 SEER.

OTOH, the RPMC-030JAZ (12 SEER)with the RBHK-21 air handler with an RCHJ-36A1 coil will net

13.8SEER, 11.85EER, COP 3.52, HSPF 7.15. Maybe picking nits, but....

THe RPMC heat pumps with the RBHK air handlers were my premium line for many years, and I sold a lot of them.

[Gary]

That's interesting because the one thing the owner told me was that he never saw much of a difference in his electric bill going from an old 8 or so SEER unit to a 14 SEER that he was sold. So given the small lineset his 12 SEER might even go down to a 10 SEER close to where he started.

[KJPRO]

Most older GE's were in fact 1/4 LL