Trane chiller HP fault

[Kirky]

Hi all hope everyone one is well. Been asked to look at a Trane aircooled chiller ECG900. System one on the chiller keeps tripping on high pressure. Have gone for the usual suspects and cleared the coil and checked the fans all ok. Reset unit and it ran fine. However got called back a week later tripped again. I have check the running pressures suction 4.5 bar discharge 25 bar fully loaded. Have noticed that the coil is really hot. Have checked airflow accross coil ok. This chiller has been in service for 7 years and they have the same problem every summer could it simply be that the coil is undersized and during the summer with the increase in ambient and sun on the coil the unit just can't cope what you think am I missing something else

[lana]

NO you are right.

What you mention is usually the case.
The other case is : Non condensible in the system. May be previous service tech did not do a good job at the vacuum. Measure the sub-cooling.

Other thing is check the condenser location. Is the hot air (discharge of the condenser) circulating into the inlet?

Cheers

[bmundoorkote]

Cond:fan will be running.check its rotation. Some times it may be rotating opposite or filter core may be clogged partially or some times solenoid valve may be not opening fully. You can compare the readings of other circuit or chillers which is running on this same weather conditions.you can chck the calibration of the HP by using gauge reading......is it ok or not.
any way....try this
all the best

[FreezerGeezer]

I'd say the previous 2 answers have most likely covered it. I'd check the fan rotation first, then the discharge air recirculation (a very common problem in the U.K. with all the roof wells, acoustic enclosures etc.). Is the condenser fitted with some sort of acoustic housing or any ducting over the top? That'll usually stuff everything up as the contractor often forgets to tell Trane's tech. support peeps so nothing's done during install to ensure good air discharge.
If niether of those are the culprit, ring Trane with the serial & ALL the model no. (YES, all 30-odd characters!!!) and they may well (depending on who you talk to & how well they know all the tricks) be able to find out what that chiller's selection data was although it will take time.
If it's none of that, then it's time to start looking at the thermofluids if you haven't already started to.

[Kirky]

Cheers all

[goshen]

Hi all hope everyone one is well. Been asked to look at a Trane aircooled chiller ECG900. System one on the chiller keeps tripping on high pressure. Have gone for the usual suspects and cleared the coil and checked the fans all ok. Reset unit and it ran fine. However got called back a week later tripped again. I have check the running pressures suction 4.5 bar discharge 25 bar fully loaded. Have noticed that the coil is really hot. Have checked airflow accross coil ok. This chiller has been in service for 7 years and they have the same problem every summer could it simply be that the coil is undersized and during the summer with the increase in ambient and sun on the coil the unit just can't cope what you think am I missing something else

Hi kirky:
it seemes you are running on the high side if u are using r-22 ,25 bar is very high ,i think your diagnostic was correct .:)

[redroge]

when you say cleared the coil have you just brushed it, try jet washing or blowing through with ofn this usually does the trick with trane and lennox units

[centrecipew]

Check Fan set point in Configuration/ settings menu ( 13,5-17 bar ), also check what the HP limit setpoint is set to, should be around 23,5 bar- this will cycle a compressor off when the Headpressure exceeds the setpoint value.
Obviously cycling a compressor off will reduce capacity but at least some cooling will be available.
Good Luck