ISSUE DATE:
SERVICE BULLETIN SUBJECT:
VINs or MODELS AFFECTED:
COMPLETE BY:
SERVICE BULLETIN #:
LABOR OPERATION CODE:

09/19/2023
35' Valeo Pack 7 Temperature Imbalance Retrofit
Service Specified Buses
Next Service Opportunity
SC-23-128
VA57Z

Labor Table
Operation
1

Step 1 – Step

Number of
Technicians

Hours

1
3
Total Labor Time

Labor Time
(T x H)
3
3

35' Valeo Pack 7 Temperature Imbalance Retrofit
Description:
The procedure describes the process of rerouting the rooftop coolant lines so the expansion tank is
downstream of the HVAC chiller and lowers the pressure drop between expansion tank and pump
inlet.

1 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

Tools/Parts Required:
Tools and Supplies Required:
Spring Clamp Pliers
Hose Cutter
Scissors
Hose Clamps
Kit Parts Required:
065453

SERVICE KIT, 35' VALEO PACK COOLANT IMBALANCE

012108

SWIVEL BUNDLE, SPACER

1

012138

CABLE TIE, HEAVY DUTY .5WIDE 9.1" BLACK

12 EA

017011

HOSE, COOLANT, EPDM. SAE J20R3 D2. 1.0 ID"

70 in

017073

HOSE,COOLANT,EPDM,SAE J20R3 D2 .63 ID

40 in

Part Denotations:
Parts are split into three categories based on origination and labeled by installation process. Blue
designates flex hose and elbows while Red designates hardlines.
Labeled New Parts:
1

5/8” Flex Hose

017073

40 in *

3

1” Flex Hose

017011

10 in*

4

1” Flex Hose

017011

50 in*

Labeled Removed and Reused Parts:
2

“T” Hardline

18 in

5

“L” Hardline

30 in

9

“L” Hardline

50 in

Labeled Reused Parts (Not Removed):
6

Elbow Hose to Battery

6 in

7

Flexible Hose from Expansion Tank

20 in

8

Flexible Hose to Expansion Tank

10 in

10

Flexible Hose from HVAC

18 in

2 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

Procedure:
1.

Run bus in High Voltage and confirm Low Voltage batteries are charged.

2.

Turn the Bus off to deactivate High Voltage and Turn off the low voltage disconnect at the rear
of the bus.

3.

At the rear of the bus, drain coolant from the Battery system to drop the level just below the
battery sight glass in the rear cage to ensure there is no coolant in the rooftop lines.

Battery Loop
Coolant Site Glass

Figure 1

4.

Using the Proterra approved practices for rooftop work, gain access to the rooftop coolant lines.

3 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

5.

Review the current routing of the rooftop coolant lines as shown in Figure 2. Review the final
retrofit routing shown in Figure 2.
NOTE: Disregard the wires and instrumentation shown in Figure 3.

Figure 2

4 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

Figure 3

5 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

6.

Remove ONLY the highlighted coolant lines shown in Figure 4. Label the hardlines as shown in
Figure 3 according to the Labeled Removed and Reused Parts Table. Any flexible lines
attached to hardlines can be disconnected if highlighted. Retain the hardlines and spring
clamps for reuse.

Figure 4

6 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

7.

Reference Figure 5 for part callouts. Attach the #1 5/8” diameter flexible hose (PN: 017073) to the
battery and secure with retained spring clamp. Attach #1 flexible hose to the perpendicular opening of
the #2 labeled hardline so that the long part of the hardline runs towards the HVAC system and secure
with a spring clamp. Measure and cut the 1” flexible hose (PN: 017011) shown as #3 so that the bend
radius of #1 is similar to what is shown in Figure 4. Install the #3 flexible hose to the hardline and the
battery and to the #2 “T” hardline. Clamp both ends to secure. Measure and cut the 1” flexible hose (PN:
017011) shown as #4 to be connected to the HVAC system and end of the #2 “T” hardline. Apply spring
clamp to both ends of #4. Secure the coolant lines with zip ties and double mounting base circled in
green.

Figure 5
7 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

8.

Reference Figure 6 for part callouts. Attach the #5 “L” hardline to the #6 flexible hose still
attached to the battery so that the short end of the “L” points towards the battery chiller and
secure with a spring clamp. Measure and cut the #7 flexible hose attached to the expansion
tank and connect to the short end of the #5 hardline. Secure with a spring clamp. Secure the
the coolant lines with zip ties circled in green.

Figure 6

8 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

9.

Reference Figure 7 for part callouts. Attach the #9 “L” hardline to the #8 flexible hose
connected to the expansion tank. Secure with a spring clamp. Measure and cut (if necessary)
the #10 flexible hose attached to the HVAC system and connect to the end of the #9 hardline.
Secure with a spring clamp.

Figure 7

9 | Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

10. Figure 8 shows the updated coolant flow path through the coolant lines.

Figure 8

11. Fill battery loop using the charge plate fill control until the coolant level sensor light goes out.
Confirm coolant is full on the site glass at the expansion tank on the roof.
12. Turn off fill switch and turn the bus ON to activate High Voltage so the coolant pumps can
circulate.
10| Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789

13. Turn on the coolant fill pump and watch the battery coolant light until it turns off. Turn off the
coolant fill pump a few seconds after the light turns off. Watch the coolant light and repeat when
the coolant light turns on. Continue until Battery coolant light stays off for 5 minutes.
14. Drive the bus and top off after first trip. Monitor coolant level and top off as needed.
NOTE: Driving the bus shifts the air around in the system allowing more air to be purged
through the expansion tank. Best practice would be to drive a route with rolling hills to get the
best air circulation in the system.
15. Return the bus to service.

11| Page
Headquarters: 1815 Rollins Road, Burlingame, CA 94010
East Coast Manufacturing: 1 Whitlee Court, Greenville, SC 29607
West Coast Manufacturing: 383 Cheryl Lane, City of Industry, CA 91789