View Full Version : Trane scroll chiller ECGAH235 info sought PLEASE !

29-03-2012, 07:20 PM
Hi folks,
I have been looking at an ECGAH235 chiller today - it's been off for past several months due to a collapsed AHU. I have rebuilt the AHU and now turned attention to the chiller.
If anyone can help with relevant cicuit diagrams and manuals it would be greatly appreciated

After repairing leaks on both circuit 1 & 2 and evacuating, charging etc, I have had the chiller running and got the chilled water down to 3.2 degrees - but it does not seem to be controlling.
I have some info but it conflicts, saying on one list that A1 is chilled water set-point and on the other list it's B10 (I think) (don't have lists with me at home).
Whatever - it ain't controlling. Both circuits will run until it goes out on LP (not sure yet if it's going out on LP switch or via LP pressure transducers.
Here's what I found so far:-
The circuit diagram pasted inside the door at time of manufacture (1996) SHOWS 3 SENSORS PER CIRCUIT. These are: -
5R51 - Water temp leaving evap (pocket at bottom of heat x)
5R58 - Refrigerant temp entering evap (pocket at opposite side of bottom of heat x)
5R56 - Saturated CDS Refrigerant temp strapped to manifold at top of condenser coil)

The evap 1 (5R51-1) Water temp leaving evaporator probe was disconnected
Both evap 1 & 2 (5R58-1&2) Refrigerant temp entering evap were disconnected
and 5R56-2 Saturated CDS Refrigerant temp (top of condenser coil) was disconnected

Not shown on the drawing (but fitted on each circuit - possibly added later and un-documented) are HP and LP pressure transducers.
Strangely these pressure tx's are connected to the controller sub boards, where the above mentioned circuit diagram shows the above probes should be connected.
I was told that a Trane Engineer has worked on this system around 18 months ago but it had proved difficult to get info from him. Its possible that another "fridge engineer" with limited knowledge worked on it too.

The chiller supplies CW to a single AHU via a ch wtr pump with a 3 port motorized valve at the AHU. The valve is controlled by a sensor in the return air duct which allows either full or partial flow thru the chiller with surplus CW being diverted back to the CW return. There IS a decrepit BMS which has some effect on the system elsewhere but as far as I can tell it's only effect on the chiller is to enable/disable it.

My biggest concern at the moment is trying to figure out how these 4 pressure transucers have been hooked into the system and if the program in the controller has been modified and if the limited info I have is correct.
Hoping for help !


29-03-2012, 11:09 PM
Found a little bit...