Choosing between Hytherm 500 and Hytherm 600 requires more than matching the number on the drum to a target temperature. You will be able to compare the two fluids against your heater, pump, expansion vessel, materials and operating records, then calculate the real delivered cost of the safer choice.
Key takeaways
- Treat Hytherm 500 and 600 as grade names, not temperature limits.
- Select the grade using bulk temperature, film temperature and pump duty.
- Inspect seals, strainers, expansion space and moisture before commissioning.
- Compare wholesalers on product traceability, technical support and delivery reliability.
What the HP data sheet actually shows for Hytherm 500 versus 600
The numbers 500 and 600 are product designations, not operating limits of 500°C and 600°C. In a hytherm 500 600 comparison, use the current HP technical data sheet, not the grade number, as the basis for heat transfer fluid selection.
| Property | Hytherm 500 | Hytherm 600 |
|---|---|---|
| Maximum recommended bulk-fluid temperature | About 300°C; confirm current HP sheet | About 315°C; confirm current HP sheet |
| Maximum film temperature | About 320°C; confirm current HP sheet | About 335°C; confirm current HP sheet |
| Kinematic viscosity at 40°C | Current HP value | Current HP value |
| Kinematic viscosity at 100°C | Current HP value | Current HP value |
| Flash point | ASTM D92 value on current sheet | ASTM D92 value on current sheet |
| Fire point | ASTM D92 value on current sheet | ASTM D92 value on current sheet |
| Density | Current HP value | Current HP value |
| Specific heat | Current HP value | Current HP value |
| Thermal conductivity | Current HP value | Current HP value |
| Vapour pressure | Current HP value | Current HP value |
| Pour point | Current HP value | Current HP value |
Viscosity at 40°C shows whether the pump can establish flow during a cold start without excessive suction loss or cavitation. Viscosity at 100°C indicates how the fluid will influence pressure drop and heat-transfer performance after circulation begins.
Flash point and fire point are safety-screening results, not allowable operating temperatures. ASTM D92 measures both; keep normal bulk and film temperatures below the applicable HP limits, and confirm every figure against the revision supplied with the quotation.
How to select the grade from heater temperature, film temperature and pump duty
Choose the grade from verified thermal and hydraulic duty, not from the higher number. Bulk temperature is the oil temperature measured in the tank or return line; film temperature is the hotter oil layer touching the heater surface.
A thin overheated film can crack the oil and form sludge or coke while the measured bulk temperature remains acceptable.
For heat transfer fluid selection, check the equipment before comparing price:
- Read the heater nameplate and manual; confirm process temperature, outlet temperature and heater watt density.
- Match required circulation rate, pipe diameter and calculated pressure drop to the pump curve.
- Check pump-suction temperature, viscosity at start-up and operating temperature, then confirm adequate NPSH margin.
- Inspect the expansion-tank arrangement, elevation, venting and available expansion volume.
| Grade | Choose it when | Do not assume |
|---|---|---|
| Hytherm 500 | Bulk and film temperatures stay comfortably below its verified limits, with better cold-start viscosity, availability, price or compatibility | “500” means 500°C |
| Hytherm 600 | The verified service envelope approaches Hytherm 500 limits, or the current HP data sheet and equipment designer specify it | The higher number automatically improves heat transfer |
Confirm the complete duty against the current HP data sheet, including maximum bulk and film temperatures. Flash point and fire point, commonly measured by ASTM D92, screen fire risk; they are not allowable operating temperatures.
Pour point does not prove pumpability after an overnight shutdown. For heat transfer oil in Bengaluru, ask for the minimum start-up temperature and viscosity limit, especially with outdoor storage, long unheated runs or small-bore lines.
What to check before filling and commissioning the circuit
Confirm compatibility before heat transfer fluid selection: the oil must suit every wetted part, not only the heater coil.
- Check carbon steel, stainless steel and copper against the current HP compatibility guidance.
- Identify elastomers, pump seals and gaskets by material and confirm their temperature and fluid-resistance limits.
- If converting from mineral oil, drain, flush and inspect the circuit for residual oil; obtain written compatibility approval before charging Hytherm 500 or 600.
- Replace seals or gaskets that have swollen, hardened or cracked.
- Calculate the complete inventory: heater coils, jackets, exchangers, piping, pump casing, filter housing and expansion tank. Size the purchase quantity and expansion vessel from this total, not pipe volume alone.
- Flush the circuit, drain all water and dry it. Water can flash to steam, expand violently, destabilise the pump or interrupt circulation.
- Fill the expansion tank only to the manufacturer’s cold level. Do not fill it completely or seal it.
- Open vents, check low-point drains, and confirm flow, low-flow, over-temperature and pump interlocks.
- Keep the heater off while the pump circulates and removes trapped air. The heater must shut down automatically on low flow.
- Raise temperature in controlled steps while watching flow, suction pressure, expansion-tank level, leaks and abnormal noise. Stop for unstable pressure, foaming, vibration or a falling level.
A cold overfill becomes a hot spill. Trapped water becomes a circulation hazard. Do not commission until the circuit is dry and air-free.
How to judge used oil and prevent avoidable fluid failure
Replace an in-service charge because its test trend has deteriorated, not because it has reached a calendar age or turned dark. Sample the circulating fluid at a consistent location and interval, then compare results with the original Hytherm specification and previous reports.
| Test | Warning trend | Response |
|---|---|---|
| Kinematic viscosity | Rising at 40°C or 100°C | Investigate overheating, contamination and degradation |
| Acid number | Rising | Check oxidation and plan controlled replacement |
| Insolubles or sediment | Rising | Inspect strainers and filter before circulation is restricted |
| Carbon residue | Rising | Check heater film temperature and deposits |
| Flash point | Falling | Stop and investigate low-boiling degradation |
| Distillation or low-boiling products | Abnormal result | Use when the fluid or laboratory method supports it |
| Oxidation stability | Falling | Review temperature control and expansion-tank exposure |
A combination of rising acidity, viscosity or insolubles with falling flash point is a stronger replacement signal than colour alone. Include laboratory oxidation-stability testing when the service is severe.
Do not mix Hytherm 500, Hytherm 600, another thermal-fluid brand, reclaimed oil or engine oil without written compatibility approval and a traceable certificate of analysis. Unapproved mixing changes viscosity, boiling range and thermal stability, undermining heat transfer fluid selection.
- Low expansion-tank level: stop, find the leak and restore the manufacturer’s cold level.
- Water contamination: shut down, drain, dry and inspect for steam damage.
- No flow, blocked strainers or inadequate NPSH: trip the heater, verify suction conditions and clear restrictions.
- Heater started before circulation: shut it down immediately and confirm flow interlocks before restarting.
How to compare HP wholesalers in Bengaluru beyond the per-kilogram price
A low per-kilogram quote is not the lowest purchase cost. Ask heat transfer oil wholesalers HP for comparison in Bengaluru for the current HP technical data sheet, safety data sheet, batch number, manufacture date, certificate of analysis, sealed-pack details, packaging format, minimum order quantity and lead time.
Authorised distribution status proves the supply channel; it does not prove that the quoted batch is physically available, sealed and ready to dispatch.
| Cost item | What to compare | Why it changes the decision |
|---|---|---|
| Product | Hytherm 500 versus Hytherm 600 price per kilogram | The cheaper grade may not suit the verified service envelope |
| Packaging | Drum or other sealed format, pack size and quantity | Part-used or unsuitable packs increase handling and storage losses |
| Delivery | Freight, taxes, hazardous-material handling where applicable, storage and lead time | A late delivery can extend a production shutdown |
| Changeover | Draining, flushing, disposal and recommissioning | A complete cleanout can erase a kilogram-price saving |
Bangalore Industrial Oils can help industrial buyers evaluate heat transfer oil in Bengaluru by matching the requested HP grade and documents with available stock, rather than treating an urgent replenishment as a price-only purchase.
- Quotation batch and documents match the selected grade.
- Quantity covers coils, jackets, exchangers, piping, pump casing, filter housing and expansion tank.
- Expansion capacity and cold fill level are adequate.
- Any existing charge is compatible, or its drain, flush and disposal are costed.
- The equipment manufacturer approves the fluid before purchase.
Related product
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Frequently asked questions
Do Hytherm 500 and 600 operate at 500°C and 600°C?
No. The numbers are product designations. Use the current HP technical data sheet for maximum bulk temperature, film temperature and other operating limits.
How do you choose between HP Hytherm 500 and 600?
Compare your heater’s bulk and film temperatures with each grade’s data sheet limits, then check viscosity at start-up temperature and the circulation pump’s duty.
What should you check before filling a heat transfer oil circuit?
Inspect the circuit for leaks, clean strainers and piping, confirm expansion-tank capacity, remove moisture, verify valve positions and record the initial oil batch number.
How can you identify avoidable heat transfer oil failure?
Trend fluid colour, viscosity, acidity, insolubles and flash point through laboratory testing. Prevent failure by controlling film temperature, air ingress, moisture and low-flow operation.
