R404A guidence wanted

[frank14]

Hi all

I am going in a few few days to have a look at an AC system. (only details I have at the mo is comp is a Carrier 5H120 and gas used is R404A). I have had very little exposure to 404 (low temp freezer room) so would appreciate an guidence on normal operating pressures and problems with POE oil etc

Regards

Frank

[nike123]

Is it AC unit or low temp freezer room? It is not clear from your question and it is unusual to have R404A in AC applications.

Pressures are depending on TD, pressure drop in lines to measuring point and air/water temperatures.
Measure air/water inlet temperatures, ad/substract TD , convert that temperature in pressure of saturated refrigerant and ad /substract pressure drop in lines. There are your expected pressures.

[Electrocoolman]

As Nike says, its unusual to use R404A in an AC.....more likely to be R407C.

POE oil is Hygroscopic...it attracts moisture, so one should not leave a system open to atmosphere for any longer than absolutely necessary.

[frank14]

Hi there, sorry about the delay, but have limited times to access the net onboard here.

my only previous experience with 404 was a small low temp freezer
The system is defintely an AC system for the vessel's living quatersAs I said only info I have on this system is that it is using the Carrier 5H 126 comp and has a cracked discharge vibro. The gas in this system as checked on the TEV is R404A. Not sure why they decided on 404 as they are using 407 on some of their other AC systems. Also not very familiar with 407 - we are sticking with R22 as long as we can

Again any guidence on problems associated with these gases would be really appreciated

Regards

[Brian_UK]

Does make you wonder if the wrong TEV had been fitted in the past.

[nike123]

Hi there, sorry about the delay, but have limited times to access the net onboard here.

my only previous experience with 404 was a small low temp freezer
The system is defintely an AC system for the vessel's living quatersAs I said only info I have on this system is that it is using the Carrier 5H 126 comp and has a cracked discharge vibro. The gas in this system as checked on the TEV is R404A. Not sure why they decided on 404 as they are using 407 on some of their other AC systems. Also not very familiar with 407 - we are sticking with R22 as long as we can

Again any guidence on problems associated with these gases would be really appreciated

Regards

Do you know history of repairs on this unit (with confidence in source credibility).

[frank14]

Hi all

The units have been "maintained" by mechanical fitters. I get the feeling they are wary of passing on what they have / have not been doing. Will have to gather as much facts as possible on site and will post again when I return

I know I have not given much info, but I thought I might get a bit of general info re operating problems for R404A, R407C and POE oil

Thanks

Frank

[Greengrocer]

Hi all

The units have been "maintained" by mechanical fitters. I get the feeling they are wary of passing on what they have / have not been doing. Will have to gather as much facts as possible on site and will post again when I return

I know I have not given much info, but I thought I might get a bit of general info re operating problems for R404A, R407C and POE oil

Thanks

Frank

If memory serves the Carrier 5F/H comps are open drive & I think the 126 size was a duplex casing with 6 or 8 cylinders. Originally these compressors were designed for use with R12, 22, 502 (they've been around since the year dot). Unless Carrier have modified them over the intervening years I would double check their suitability for use on 404a or 407c. How old is the install? Check with local Carrier service if you have one or perhaps some of our USA based brethren can assist further on this one.

[GeorgeWhaley3]

Hi, I am brand new to the site but I am designing a -20F, 30 Ton industrial chiller using a 5H120 compressor. I have a 5H60 that I am replacing. I am not sure which refrigerant I am going to use.
This info will give you 40 pages of application data on using 404A, 507 R22, 134A etc.
I can not cut and paste the link because I am new to the site. Maybe it will help. Good Luck

go to Carrier.com marinesystems and search for "510-509 5FHAppGuide 5fh 09rh-2xa.pdf"

[frank14]

Hi guys

Sorry about the delay, have been moving around and had net access issues.
The condensing unit's and AHU's are supplied by Carrier Malaysia and are stamped R404A. System was installed last year. There are no commissioning or as built records onboard.
They have twice had broken valves on the heads nearest shaft seal.
Besides replacing the leaking vibro, I was not able to spend much time on that system as they had problems with some units where they had moisture, NCG's and R404 mixed in R407C systems, but was able to take a few readings.

Suction Pressure = 300 KPa, Discharge P = 1680 KPa Oil P = 780 KPa, Cond water in = 31 C, Cond water out = 35 C, Cond liquid line temp = 37 C, AHU air in = 25C, AHU air out = 12 C, Suction leaving AHU = 16 C,
Comp motor amps 168 A, FLA = 192 A, AHU fan motor amps 45 A, FLA = 59 A
Cond unit +/- 6m below and 30 m across from AHU

My feeling is that they are a bit short of air through AHU and short of refrigerant ?

Any feedback appreciated

Frank

[nike123]

Hi guys

Sorry about the delay, have been moving around and had net access issues.
The condensing unit's and AHU's are supplied by Carrier Malaysia and are stamped R404A. System was installed last year. There are no commissioning or as built records onboard.
They have twice had broken valves on the heads nearest shaft seal.
Besides replacing the leaking vibro, I was not able to spend much time on that system as they had problems with some units where they had moisture, NCG's and R404 mixed in R407C systems, but was able to take a few readings.

Suction Pressure = 300 KPa, Discharge P = 1680 KPa Oil P = 780 KPa, Cond water in = 31 C, Cond water out = 35 C, Cond liquid line temp = 37 C, AHU air in = 25C, AHU air out = 12 C, Suction leaving AHU = 16 C,
Comp motor amps 168 A, FLA = 192 A, AHU fan motor amps 45 A, FLA = 59 A
Cond unit +/- 6m below and 30 m across from AHU

My feeling is that they are a bit short of air through AHU and short of refrigerant ?

Any feedback appreciated

Frank

According to your data, you have some subcooling. That mean that for present condition you have enough refrigerant. You also have 13K ΔT at evaporator which suggest that you have shortage of air flow.

First ting to do is to ensure enough air-flow so that ΔT is about 10K.

Your superheat and TD at evaporator is high, but you must first resolve air problem and then measure again your system pressures and temperatures.

[icecube51]

at the start of this topic i had a small mind spill.
the one ho invents a tool whitch can tell wat cind of gaz there is in the system, is going to fill a hole in the marked ???? i think....

Ice

[juma]

iam experiencing high discharge pressures when using R404a about 19bars, condenser water temperatures of 77F,compressor type is semi-hermetic screw 75hp. plz help?

[Emmett]

Juma,
Start a new thread and provide more details, from what you have provided I can only conclude you have a condenser issue.