Hytherm 500 and Hytherm 600 are heat-transfer fluids, not automatic substitutes for bearing, gear, chain, compressor or hydraulic oils. By comparing the manufacturer’s temperature and physical-property data with your heater design, circulation rate, film temperature and process duty, you can select a grade without confusing a dealer category with an application approval.
Key takeaways
- Use Hytherm only in indirect heating circuits, not bearings, gears or hydraulic systems.
- Compare maximum bulk and film temperatures, viscosity and circulation requirements.
- Check seals, hoses, metals and flushing needs before changing heat-transfer fluids.
- Ask for sealed packs, batch details, technical data and a delivered-cost comparison.
First identify whether your equipment needs heat-transfer fluid or machinery oil
Hytherm 500 and Hytherm 600 are heat-transfer fluids for indirect heating circuits, not lubricants for bearings, gears, chains, compressors or hydraulic equipment. A pump circulates the fluid through a heater and then through a jacket, coil or heat exchanger, where it transfers heat without contacting the product.
A general-purpose machinery oil listing can therefore put the wrong fluid in the wrong system. Search results for “general purpose machinery oil dealers hytherm 500 600 details in hubballi” do not prove that the seller understands heat-transfer service or has supplied the correct grade.
- Machinery oil may have the wrong viscosity for the circulation pump, causing poor flow, high pressure loss or pump damage.
- Its additive package and oxidation behaviour may not suit prolonged high-temperature service, allowing sludge, deposits or rapid fluid degradation.
- A fluid with an unsuitable flash point or film-temperature limit can create hot spots, vapour formation and a fire risk at the heater surface.
Hytherm 500 is generally described as a highly refined mineral-oil-based heat-transfer fluid, while Hytherm 600 is positioned as a synthetic, higher-temperature grade. Do not choose from the word “oil” or the product number alone. Confirm that your equipment requires heat-transfer fluid, then obtain the current manufacturer datasheet and written confirmation of the quoted Hytherm grade.
Hytherm 500 versus 600: compare the datasheet, not the product number
Choose from the manufacturer’s current technical data sheet, not from the number in the name. Hytherm 500 is generally specified for maximum bulk-fluid temperature of about 285°C; Hytherm 600 is the higher-temperature grade, generally specified around 320°C. Those figures do not establish the permissible heater-wall or film temperature.
| Specification | Hytherm 500 | Hytherm 600 |
|---|---|---|
| Operating temperature range | Verify the current data sheet | Verify the current data sheet |
| Maximum film temperature | Obtain the stated limit | Obtain the stated limit |
| Recommended maximum bulk temperature | About 285°C | About 320°C |
| Kinematic viscosity at each stated temperature | Compare exact values | Compare exact values |
| Flash point and fire point | Record both values | Record both values |
| Density | Compare at the stated reference temperature | Compare at the stated reference temperature |
| Specific heat and thermal conductivity | Compare heat-transfer capacity | Compare heat-transfer capacity |
| Vapour pressure | Check against expansion-tank and system-pressure design | Check against expansion-tank and system-pressure design |
For hytherm 500 versus 600, request the manufacturer’s exact values rather than accepting a dealer’s summary. The base fluid also matters: Hytherm 500 is generally mineral-oil-based, while Hytherm 600 is positioned as synthetic. That difference affects viscosity, oxidation life and replacement cost.
Before ordering, ask for:
- The current product data sheet and recommended operating limits
- The specified maximum film temperature, not only bulk temperature
- Batch or lot identification and a certificate of analysis where available
- Written confirmation that the quotation names Hytherm 500 or Hytherm 600 exactly
Match the grade to bulk temperature, film temperature and circulation
A 280°C heater outlet does not prove Hytherm 500 is safe: a restricted passage or fouled heater can create a much hotter film at the metal wall. Select the grade against the hottest wall temperature and the supplier’s maximum film-temperature limit, not the controller set-point.
| Grade | Approximate maximum bulk temperature | Selection signal |
|---|---|---|
| Hytherm 500 | About 285°C | Suitable only when measured bulk and calculated film temperatures remain within its datasheet limits |
| Hytherm 600 | About 320°C | Provides the higher-temperature margin when the system design exceeds the 500-grade bulk or film limit |
Use these readings to test the selection:
- Heater outlet temperature shows the hottest measured bulk point. Compare it with the grade’s maximum bulk temperature, leaving the margin specified by the equipment and fluid supplier.
- Return temperature shows how much heat the process removes. A small outlet-to-return difference with a heavy heater load can indicate excessive flow; a large difference can indicate inadequate flow or poor heat removal.
- Flow rate determines heater-wall cooling. A low reading, partly blocked passage or undersized pump can overheat the film while outlet temperature remains acceptable.
- System pressure confirms that the pump, restrictions and expansion arrangement operate within design limits. Pressure does not make a lower-temperature grade suitable.
- Local heater-wall temperature is the deciding measurement where available. Check hot spots caused by burner impingement, fouling or poorly tuned electric elements.
Obtain each grade’s maximum film temperature, viscosity at start-up, and thermal-stability limits from the complete technical sheet before choosing. India’s local climate does not change the grade; design temperature, circulation and heater duty do.
Check system materials, fluid compatibility and changeover risks before filling
A partly blocked heater passage can create a dangerously hot film even when the outlet-temperature display looks normal. Inspect the complete circuit before choosing either grade.
1. Check the expansion tank for adequate empty expansion volume, correct venting or inert-gas arrangement, and a level indication that remains visible during heating. Remove water and confirm the tank is suitable for the fluid’s maximum temperature.
2. Verify the pump is sized for the fluid’s viscosity at the lowest start-up temperature, not only at operating temperature. Inspect the mechanical seal, shaft seal and bearings for leakage or heat damage.
3. Confirm that seals, gaskets and hoses are rated for the fluid chemistry and maximum bulk and film temperatures. Replace swollen, brittle or softened elastomers, and obtain written compatibility confirmation for the exact materials before filling.
4. Inspect the heater for scale, sludge, restricted passages and poor flow distribution. Check valves for correct temperature and pressure ratings, and confirm that bypass, isolation and drain valves operate fully.
5. Calibrate temperature, pressure, flow and level instruments. Test high-temperature cut-outs and low-flow protection; a failed interlock can turn a circulation fault into local fluid degradation.
6. Do not mix Hytherm 500 or Hytherm 600 with fluid already in the circuit, including another supplier’s fluid, unless the supplier approves that combination. Base chemistry and additive packages can react or reduce thermal stability.
An approved changeover requires draining, checking residual fluid, flushing as instructed, drying the system and filling with the selected grade.
Ask a Hubballi dealer for evidence, sealed supply and a total-cost comparison
Request these items before accepting a quotation from a Hytherm-series dealer in Hubballi:
- The current manufacturer data sheet for the quoted grade
- Written confirmation stating Hytherm 500 or Hytherm 600
- Batch or lot number, sealed-pack confirmation and manufacturing details
- Certificate of analysis, where available
- Recommended bulk-temperature and film-temperature limits
- Delivery charges, taxes, drum size, payment terms and lead time
Heat-transfer-fluid specifications in Hubballi are not a separate climate-based grade. Your system design temperature, heater type, circulation rate, expansion-tank arrangement and process duty determine selection; local conditions mainly affect storage and start-up pumping. Bangalore Industrial Oils should provide the same traceability documents and written grade identification as any other supplier.
Compare the quotation using the complete operating interval, not only the delivered price per litre.
| Comparison basis | Hytherm 500 | Hytherm 600 |
|---|---|---|
| Delivered fluid cost | Price, freight, taxes and usable litres | Price, freight, taxes and usable litres |
| Replacement cost | Litres drained multiplied by delivered cost | Litres drained multiplied by delivered cost |
| Condition-related cost | Heater deposits, cleaning and disposal recorded from your plant | Heater deposits, cleaning and disposal recorded from your plant |
| Downtime cost | Drain, flush, refill and lost production hours | Drain, flush, refill and lost production hours |
Use actual heater-wall temperature, bulk and return temperatures, fluid analysis and deposit records to test those estimates. A higher-priced grade earns its place only when documented longer service, fewer cleanings or less downtime outweighs its purchase premium.
Do not mix either grade with the existing fluid unless the supplier approves the chemistry and supplies a written flushing procedure.
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Frequently asked questions
How do you know whether you need heat-transfer fluid or machinery oil?
Choose heat-transfer fluid for an indirect heating circuit that circulates fluid through a heater, jacket, coil or heat exchanger. Choose machinery oil for lubricating bearings, gears, chains, compressors or hydraulic equipment.
What should you compare between Hytherm 500 and Hytherm 600?
Compare the datasheets for maximum bulk temperature, maximum film temperature, viscosity at operating and ambient temperatures, flash point, pour point and circulation requirements. Do not choose from the product number alone.
Why do bulk temperature and film temperature both matter?
Bulk temperature measures the circulating fluid, while film temperature reflects the hotter layer touching the heater surface. A fluid can remain within its bulk limit while overheating at the heater film.
What should you check before filling a heat-transfer system?
Confirm compatibility with the heater, pump, pipes, seals, hoses, expansion tank and heat-exchanger metals. Review residual-fluid mixing, flushing, drain-down and disposal requirements before changing grades.
What evidence should you request from a Hubballi dealer?
Ask for the current technical data sheet, safety data sheet, sealed original packaging, batch or lot number, manufacturing date and traceable invoice. Compare delivered price with the required volume, flushing work and disposal cost.
