01Align the duty and calculation basis
Confirm that each proposal uses the same fluid, flow, inlet and outlet temperatures, operating and design pressure, ambient conditions, supply and operating mode. Different flow references, design margins, heat losses and warm-up times can change rated power and equipment size.
Ask suppliers to state key assumptions and distinguish heater rating, normal operating load and startup duty. If process conditions are not final, list open items so each supplier does not price against a different basis.
02Compare materials and mechanical construction
- Pressure-boundary, element-sheath and sealing materials
- Design temperature, design pressure, connection standard and size
- Element construction, watt density and maintenance method
- Insulation, supports, vents, drains and field accessories
- Applicable design code, inspection and test scope
Check material grades against fluid chemistry and temperature. A higher grade name or larger appearance does not by itself make a proposal more suitable.
03Verify electrical control and protection scope
Compare supply voltage, phase, wiring, control panel, staged or modulating control, sensors, protective devices and interlock signals. Confirm whether fan, pump, flow, level or pressure interfaces are included and what the site must provide.
Base protection on process risk and applicable requirements. Alarm, trip, reset and redundancy logic can differ between proposals; ask each supplier to describe its sequence.
04Include documents, acceptance and service
Confirm whether the quote includes general arrangement and wiring drawings, material records, calculations, inspection reports, conformity documents, operating instructions, spares and packing. Also clarify lead-time start, site service, warranty scope and spare-parts response.
A technical deviation list with “compliant,” “deviation” and “to be confirmed” entries makes the commercial comparison more meaningful after technical clarification.