THERMAL OIL HEATER MODEL CODES
YYW vs YYL vs YLW vs YGL Thermal Oil Heater Guide
These model families can help classify a Chinese thermal oil heater enquiry, but letters alone do not define the final equipment. Use them as a starting point, then verify fuel, layout, duty, circulation and complete system scope.
QUICK ANSWER
Treat the code as a family label, not a complete specification.
YYW / YYL
Commonly associated with gas- or liquid-fuel thermal oil heaters, with horizontal or vertical layout conventions depending on the supplier and standard used.
YLW
Commonly associated with horizontal solid-fuel systems using a travelling or chain-grate combustion arrangement.
YGL
Commonly associated with a vertical solid-fuel organic heat-carrier heater, often applied to biomass or coal projects.
Procurement rule: the signed data sheet, general arrangement drawing, fuel specification and scope list control the project—not an assumed meaning of the model letters.
01 · TERMINOLOGY
Model letters shorten communication, but conventions can differ.
Industrial buyers may receive quotations using YYW, YYL, YLW, YGL or a combined expression such as YY(Q)L. These codes are widely recognized in Chinese boiler-market terminology, yet suppliers may apply them with different punctuation, capacity units and product boundaries.
Before comparing quotations, ask each bidder to state the fuel, heater orientation, combustion method, rated useful duty, design temperature, operating pressure, test basis and included equipment. This removes ambiguity created by model naming.
02 · MODEL-FAMILY SCREENING
Use this table to route the enquiry to the right engineering discussion.
| Model family | Common market association | Items that still require confirmation |
|---|---|---|
| YYW | Horizontal gas- or liquid-fuel thermal oil heater | Fuel, coil arrangement, burner, duty, fluid flow and pressure drop |
| YYL / YY(Q)L | Vertical gas- or liquid-fuel thermal oil heater; “Q” is often used when gas firing is identified | Exact layout, model capacity basis, burner and complete thermal-oil system |
| YLW | Horizontal solid-fuel heater, frequently with chain or travelling grate | Fuel analysis, grate, furnace, draft, ash and emissions equipment |
| YGL | Vertical fixed-grate or compact solid-fuel organic heat-carrier heater | Fuel size and moisture, feeding method, operating range and emissions scope |
These descriptions are procurement guidance, not a universal legal decoding rule. Verify the manufacturer’s model definition on every project.
03 · GAS AND LIQUID FUEL
YYW and YYL selection starts with duty, temperature and burner data.
For gas- or oil-fired systems, specify useful heat duty at normal and peak load, supply and return oil temperatures, selected thermal-fluid properties, fuel pressure and composition, altitude, emissions limit and required turndown. Horizontal and vertical layouts can affect plot use, shipping envelope, access and coil arrangement, but neither orientation is automatically superior.
JIELI publishes a preliminary 2–12 million kcal/h gas-fired thermal oil heater selection guide. The capacity label must still be checked against the real process heat balance and circulation design.
04 · BIOMASS AND COAL
YLW and YGL are combustion-system decisions, not only heater-body decisions.
A biomass or coal project must define fuel species, moisture, particle size, ash, volatile matter, heating value and expected variation. Those properties affect storage, feeding, furnace volume, grate selection, combustion air, furnace draft, dust collection, ash handling and control response.
YLW is commonly discussed for larger horizontal chain-grate or travelling-grate systems. YGL is commonly discussed for vertical solid-fuel arrangements. The right system depends on duty and fuel behavior; a low-cost heater body cannot compensate for unsuitable fuel preparation or draft control.
05 · DUTY AND TEMPERATURE
Convert model capacity into one consistent engineering basis.
Suppliers may state capacity in kW, MW, kcal/h or MMBtu/h. Use one conversion basis and distinguish useful process duty from fuel input. As a screening conversion, 1,000,000 kcal/h is approximately 1.163 MW of useful heat. Final fuel input is higher and depends on guaranteed efficiency at the declared load.
Thermal-oil circulation follows the process duty, fluid heat capacity and design temperature difference. A model with sufficient burner capacity can still be unsuitable if coil velocity, pressure drop, pump duty, expansion system or thermal-fluid film temperature is not correctly engineered.
PUBLISHED JIELI DATA
The model tables show why the code and hydraulic data must be read together.
| Published JIELI family | Rated capacity range | Published circulation range | Published main-pipe range |
|---|---|---|---|
| YY(Q)L vertical gas / fuel-oil-fired | 2,000,000–12,000,000 kcal/h | 160–600 m³/h | 200–400 mm |
| YLW horizontal biomass-fired | 1,200,000–20,000,000 kcal/h | 100–1,350 m³/h | 150–600 mm |
These are the ranges currently published in JIELI’s preliminary product tables, not guaranteed values for an unconfirmed project. A buyer should use the model code to find the appropriate family, then verify the exact row against the selected fluid, temperature difference, coil pressure drop, fuel and site conditions.
The JIELI project archive also documents gas-fired thermal-oil references from 1,000,000 kcal/h in the United States to 10,000,000 kcal/h in Saudi Arabia, plus biomass references including 3,000,000 kcal/h for Chile and 6,000,000 kcal/h for Argentina. Those cases establish manufacturing and delivery context; they do not replace a new project calculation.
06 · SYSTEM BOUNDARY
Compare the heater island and the thermal-oil loop together.
| System area | Typical items to define |
|---|---|
| Heater and combustion | Coils, casing, burner or grate, fuel train or feeding, fans, controls and heat recovery |
| Thermal-oil circuit | Circulation pumps, expansion tank, low tank, separator, filters, valves and instruments |
| Flue gas and emissions | Air preheater or economizer, dust collector, induced-draft fan, duct and chimney |
| Site interfaces | Foundations, piping, cabling, insulation, erection, commissioning and documentation |
Request a written battery-limit drawing. Two quotes carrying the same model letters may include very different plant boundaries.
Model-neutral thermal oil heater RFQ checklist
- Normal and peak useful heat duty in kW or MW;
- Thermal-fluid brand or property table and maximum recommended temperatures;
- Supply and return temperatures at each process user;
- Calculated flow, circuit pressure drop and elevation profile;
- Fuel analysis, pressure, availability and required operating range;
- Site altitude, ambient conditions, emissions limit and code;
- Plot, shipping and maintenance-access constraints;
- Complete included equipment, exclusions and responsibility matrix.
RELATED ENGINEERING
Move from model code to complete-system selection.
FREQUENTLY ASKED QUESTIONS
YYW, YYL, YLW and YGL FAQ
What do YYW and YYL mean on a thermal oil heater enquiry?
They are model-family designations commonly used by Chinese suppliers for liquid-fuel or gas thermal oil heater arrangements, often with horizontal or vertical layout conventions. The exact construction, fuel and scope must be confirmed from the supplier data sheet and general arrangement drawing.
What is a YLW thermal oil heater?
YLW is commonly associated with a horizontal solid-fuel thermal oil heater using a travelling or chain-grate combustion system. Fuel specification, furnace, grate, draft, ash and emissions equipment must be selected as one system.
What is a YGL thermal oil heater?
YGL is commonly associated with a vertical solid-fuel organic heat-carrier heater, often for biomass or coal applications. Actual configuration and capacity range vary, so the project drawing and technical specification are controlling.
Can I select a thermal oil heater from the model code alone?
No. Confirm useful duty, supply and return temperatures, fluid properties, circulation flow, pressure drop, fuel, emissions, site conditions, code and complete supply boundary before selecting equipment.
JIELI THERMAL ENGINEERING
Send process data instead of only a model code.
JIELI can translate duty, temperature, fluid, fuel and site constraints into a gas, oil, biomass or coal thermal-oil system proposal with a defined supply boundary.
Request a model and system review