York YCIV and YCAV air-cooled screw chillers cool the VSD with a closed glycol loop. Fill it only with York's approved coolant, never water. Forms 201.23-NM2 (YCIV) and 201.21-NM1 (YCAV) say to keep the level 9 to 15 inches (23 to 38 cm) below the top of the fill tube and to change the coolant 5 years from the equipment's ship date. On the YVAA, Johnson Controls bulletin SI0338 fills the loop at a stand pipe to 14 inches from the bottom of the pipe.
What does the VSD glycol loop do?
Form 201.21-NM1 says the VSD makes heat in its IGBT power modules and SCR/diode assemblies, and that heat has to be removed. The loop works like this:
- The coolant feeds a liquid-cooled heatsink, called a chillplate, under the IGBT and SCR/diode modules.
- A circulator pump moves the coolant through tubes in the lower rows of the condenser coils. The condenser fans reject the heat there.
- The same loop feeds a small coil in the Micro/VSD cabinet, with a fan blowing cabinet air across it.
Form 201.23-NM2 says the same for the YCIV: "The VSD is cooled by a glycol loop and circulating pump." For when the pump and fans run and for baseplate temperature faults, see York Air-Cooled Chiller VSD Faults: Low DC Bus and High Baseplate Temp.
What coolant goes in the loop?
Both manuals require the approved coolant and give these warnings:
- "Always fill the system with approved coolant to avoid damage to the pump seals and other components."
- "Mixing other coolants or water with the special glycol will reduce the life of the coolant." It can lead to VSD overheating and damage.
- "Substituting coolant or adding water will result in cooling loop performance loss and chiller shutdown."
None of the York documents cited here gives a part number for the VSD coolant. Our YCIV, YCAV, YVAA and QTC4 model pages list 013-03344-000 (Coolant Propylene Glycol, 5 gallon), but no York document we read ties that part number to the VSD loop. Confirm the approved coolant for your unit by model and serial number before you add anything to the loop.
How do you top off a YCIV or YCAV VSD loop?
| Step | What 201.23-NM2 (YCIV) and 201.21-NM1 (YCAV) say |
|---|---|
| Before starting the pump | "Never run the glycol pump without coolant!" Running dry can damage the pump seals. Fill the tube to the required level first, because the level may drop when the pump starts. |
| Level | Keep it 9 to 15 inches (23 to 38 cm) from the top of the fill tube. Check before running the pump. |
| Pump running | Top off as needed while the pump runs. Reinstall the cap before stopping the pump so the tube doesn't overflow. |
| Running the pump for service | 201.21-NM1: the pump can be run by putting the chiller in Service Mode. |
| Coolant life | "System coolant should be changed 5 years from date of shipment of the equipment." |
Form 201.23-NM2 shows where the glycol pump and fill tube are in its glycol system component figures, at the rear of the VSD panel.
How do you fill a YVAA VSD glycol loop?
The YVAA Style A maintenance table in form 201.28-NM1.1 includes a "VSD Glycol Change" row. Johnson Controls Service Information SI0338 (117), "Microchannel VSD Outdoor Glycol Coil," gives the fill steps for YVAA units after replacing that coil:
- Make sure the system has been drained and flushed once with fresh glycol.
- Fill the stand pipe with fresh glycol until it is 14 inches from the bottom of the stand pipe.
- Run the glycol pump for 10 seconds using service mode.
- Repeat the fill and pump steps until no air bubbles show or the level stays constant.
- Run the system for 30 minutes, recheck the level and add glycol as needed.
SI0338 Table 1 lists flushing, system fill and total glycol quantities by YVAA model and number of glycol coils, with totals of 10 or 15 gallons. Use the row for your model.
Don't mix up the two glycols
The YCIV and YVAA maintenance tables have two glycol rows. "Check Glycol concentration on Low Temp. or other applications where freezing may be a problem" is about the chilled-liquid side. "VSD Glycol Change" is about the drive cooling loop. They are separate fluids. Never top off the VSD loop from the building's glycol.
Parts involved
| Component | Role | Where to find it |
|---|---|---|
| Propylene glycol coolant (store listing) | Listed on the YCIV Style A, YCAV Style A, YVAA Style A and B and QTC4 Style A pages. York's manuals don't give the coolant part number, so confirm it is the approved VSD coolant for your unit. | York 013-03344-000 Coolant Propylene Glycol 5 Gallon | OEM Chiller Part |
| Centrifugal pump | Listed on the same model pages. Match the part number on your glycol pump before ordering. | York 026-41611-000 Pump, Single Stage, Centrifugal | OEM Chiller Part |
| Coolant test | Store listing for a VSD coolant test. Not tied to a York procedure in the documents above. | York 013-04131-000 VSD Coolant Validation Test | OEM Chiller Part |
| Cooling fan | Listed on the YCIV and YVAA Style A pages. Confirm by part number. | York 025-32557-000 Fan, Cooling 115V, 70W 330CFM | OEM Chiller Part |
| Other pumps and chemicals | Browse by type. | York Chiller Pumps and York Chiller Compressor Oil & Chemicals |
Which York units this applies to
- YVAA Style A: VSD glycol change is in the 201.28-NM1.1 maintenance table. Fill per SI0338.
- YVAA Style B: later YVAA. Confirm the fill method in its own manual.
- YCIV Style A: 9 to 15 in. from the top of the fill tube, 5-year change, per 201.23-NM2.
- YCAV Style A: same level and change interval, per 201.21-NM1.
- QTC4 Style A: 013-03344-000 coolant and the 026-41611-000 pump are listed on its model page. Confirm the procedure for your unit.
Scope: York form 201.23-NM2 (YCIV0157 to YCIV0397 Style A, 60 Hz), form 201.21-NM1 (YCAV0157 to YCAV0267 Style A, 60 Hz), form 201.28-NM1.1 (YVAA Style A) and Johnson Controls SI0338 (117) (YVAA microchannel VSD outdoor glycol coil). Other YVAA styles, the YVFA and 50 Hz units have their own documents.
Before you order
Note the chiller model and serial number from the nameplate, and the part number on the pump or coolant container if you have it. Then contact us at help@totalhvacparts.com or 610-487-7999 to confirm the coolant and parts for your unit.
Frequently Asked Questions
Can I add water to a York YCIV or YCAV VSD coolant loop?
No. Forms 201.23-NM2 and 201.21-NM1 say substituting coolant or adding water will cause cooling loop performance loss and chiller shutdown, and that mixing water with the special glycol shortens its life.
What level should the York YCIV VSD glycol be?
Form 201.23-NM2 says to keep it between 9 and 15 inches (23 and 38 cm) from the top of the fill tube. Check it before running the pump, and top off while the pump runs.
How often should York VSD coolant be changed?
The YCIV and YCAV manuals say system coolant should be changed 5 years from the equipment's date of shipment.
How do you bleed air from a York YVAA VSD glycol loop?
SI0338 says to fill the stand pipe to 14 inches from the bottom and run the glycol pump for 10 seconds in service mode. Repeat until no air bubbles show or the level holds, then run 30 minutes and recheck.
Can the York VSD glycol pump run dry?
No. Both manuals warn "Never run the glycol pump without coolant!" because it can damage the pump seals. Fill the tube before starting the pump.
Sources
- York form 201.23-NM2, YCIV0157 to YCIV0397 Style A (60 Hz) installation, operation and maintenance (VSD cooling, p.224; glycol system components, pp.188-189; maintenance requirements, p.316)
- York form 201.21-NM1, YCAV0157 to YCAV0267 Style A (60 Hz) installation, operation and maintenance (VSD cooling and cooling loop, p.200)
- York form 201.28-NM1.1, YVAA Style A installation, operation and maintenance (maintenance requirements, p.164)
- Johnson Controls Service Information SI0338 (117), Microchannel VSD Outdoor Glycol Coil (YVAA) (fill procedure, Table 1 glycol quantity)
- Live product titles for the parts listed above, as shown on each product page
The VSD cabinet holds dangerous voltage and stored charge, and the glycol pump must never run dry. Service should be performed only by qualified personnel, following York's manual for your unit and your facility's lockout/tagout procedures.