Trane Intellipak - High Pressure

[dixie2005]

Looking for some advice. Trane intellipak's, two 40 ton and two 50 tons serving the building. R-407C. All units are having high-pressure trips causing the "compressor trip" diagnostic. I've been getting this alarm on all units. The pressure is in the 325 - 375 psig range.

So far, all we have really done is thoroughly cleaned the condensers, the pressure remains high. I'm considering recovering all the refrigerant out of one of the circuits to measure the charge...but it just seems so odd that I'm having the same issue with all four units, eight circuits in total! If it were one circuit, I could see the possibility of overcharge, or non-condensibles, or restricition, defective txv etc...but all eight circuits with the same issue seems odd.

Condenser fans are all working and rotation is correct. The issue is worse when the second compressor (two compressors in parallel per circuit) kicks in.

It seems like the condenser is undersized, could it be possible? We're only talking about a 85F outside air temp yesterday when I checked all circuits.

Does anyone have any advice on this?

Thanks,

[B1978]

Its overcharged. I would check the specs on on 407C to verify the correct charge amount. I cleaned the coils on an Intellipak, they looked clean, and had the same issue, to again go back with foaming coil cleaner, and that fixed the issue.

[Southern Mech]

Clean with gas pressure washer, be willing to bet coils are impacted with dirt

[Six]

You literally have to split the coils on some Trane units to clean them properly.

Also I wouldn't reclaim R407C if I could help it. It has a huge glide and is a terrible replacement for R22

[toptwo]

See if the unit has split coils, some even are 3 rows deep. Can't recall any intellipacks having 3 rows but make sure.

[Tommy knocker]

All 4 doing same thing screams dirty coils. However need alittle more info. Are they newer units. Did you just take them over from someone else. Check to see if you have any subcooling. No subcool keep cleaning. High subcool get the recovery machine. Never seen an intelipac with split coils myself but I ain't seen it all yet. Gut says get the NuBrite and lay it on strong. Good luck.

[FixItRight]

The unit was R22 and was changed to 407C right?

[hands]

What was the suction pressures, SH and SC. I have never seen a Intellipak with splitable coils, but they are thick, so they could be dirty in the middle. Check the delta T across the condenser coils to see if they need cleaned again.

[maxster]

heat has to be on those liquid lines if it isn't going off the condensers,chances of over charge on 8 Ckts? only thing common is the air and those condensers they have to be dirty.if it was a replaced freon situation Trane had to spec the charging of the 407C with the exsisting condensers...from 22

[FixItRight]

heat has to be on those liquid lines if it isn't going off the condensers,chances of over charge on 8 Ckts? only thing common is the air and those condensers they have to be dirty.if it was a replaced freon situation Trane had to spec the charging of the 407C with the exsisting condensers...from 22

Trane does not spec for changing R22. They say they only want you to use R22 and if you use a replacement it will void any warranty that is left.

[dixie2005]

The unit was R22 and was changed to 407C right?

no it was built 407c

[dixie2005]

What was the suction pressures, SH and SC. I have never seen a Intellipak with splitable coils, but they are thick, so they could be dirty in the middle. Check the delta T across the condenser coils to see if they need cleaned again.

the coils do not split, but i do know what you guys are referring to, i've cleaned those types of coils as well. i have cleaned those coils twice with the blue nu-calgon, very strong acid foaming cleaner. and i always use a 3000 psi gas pressure washer. you can easily get at both sides of the coil on these units, and i have cleaned them thoroughly from both sides.

[dixie2005]

What was the suction pressures, SH and SC. I have never seen a Intellipak with splitable coils, but they are thick, so they could be dirty in the middle. Check the delta T across the condenser coils to see if they need cleaned again.

i didn't take heat measurements on all circuits, but the one i checked had over 40 degrees of subcooling and 30 degrees of compressor superheat. the head pressure was high when these measurements were taken (340 psig) so when the system is operating that far away from design, it makes it more difficult for me to interpret the data. from looking at that subcooling measurement, i think my next step is to recover the refrigerant from one of the circuits to check charge. i will also check the p/t relationship at this time too - that's something i have not done yet. perhaps someone assumed r22 refrigerant and the charge is mixed? it's just really throwing me off that all the circuits are having the same issue...

in any event, i have to do something because the basics are covered off and i'm still having the issue. trane tech support was not helpful, they just told me to do the things i have already done. we don't have a history with these units so i don't know if this has always been an issue. the customer said that the previous service provider had to reset them a lot but said it was normal. this summer is exceptionally hot for our area and i'm sure this is why the problem is coming up now.

the building is about 5 years old, and that would be the age of the units as well. the equipment and building was never properly commissioned or completed. the building was vacant until about 1.5 years ago... that might be the reason this was never dealt with until now....

tomorrow i will check:
- p/t relationship on one of the circuits
- weigh-out the refrigerant charge on one of the circuits
- the specs on the installed txv
- the temperature difference across the condenser

anything else?