HFT40002Z-01 Open One-Way Temperature Limit Valve at Low Temperature
The Legom HFT40002Z-01 Open One-Way Temperature Limit Valve at Low Temperature is a G1 thermostatic one-way valve that opens when water temperature falls below the preset threshold and closes when temperature rises above it — the G1 (DN25) counterpart to the G1/2 HFT33009Z-01, providing the same low temperature opening function at higher flow capacity for larger domestic and light commercial applications.
Featuring an electroplated integrated water inlet connector and electroplated handwheel on a 57-3 copper body, the HFT40002Z-01 suits OEM water heater thermostatic management, hot water recirculation control, and solar thermal low temperature detection circuits where G1/2 flow capacity is insufficient. Temperature adjustment range 20–60°C, control accuracy ±2°C, working pressure range 0.03–1 MPa.
Key Benefits
- Low temperature opening at G1 (DN25) flow capacity – Opens when water temperature falls below the preset threshold, providing automatic flow activation based on low temperature detection at a bore size suited to larger domestic storage systems and light commercial applications beyond G1/2 capacity
- Electroplated integrated water inlet connector – Premium metallic electroplating on the integrated inlet connector combines reduced external fitting count with a high-specification surface finish at the connection point
- Electroplated handwheel – Metallic surface finish on the ABS handwheel for premium OEM product appearance and visible installation coordination
- ±2°C temperature control accuracy – Precise threshold detection for consistent open/close behavior at the defined low temperature set point
- 20–60°C adjustment range – Wide set point range covering the full spectrum of domestic hot water low temperature threshold requirements
- No electricity required – Self-acting thermostatic operation powered entirely by sensed water temperature
- 57-3 copper body – Durable copper alloy construction for potable hot water service
- Wide pressure range 0.03–1 MPa – Covers gravity-fed through standard mains-pressure applications
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | HFT40002Z-01 |
| Valve Type | One-way, low temperature opening, fixed temperature |
| Body Material | 57-3 copper |
| Handwheel | ABS with electroplating |
| Inlet Connector | Electroplated integrated water inlet connector |
| Connection | G1 internal thread (DN25) |
| Temperature Adjustment Range | 20–60°C (standard); 35–55°C / 40–50°C / 30–60°C (preset options) |
| Temperature Control Accuracy | ± 2°C |
| Working Pressure Range | 0.03 MPa – 1 MPa |
| Ideal Working Pressure | 0.1 MPa – 0.5 MPa |
| Cold Water Temperature Range | 5°C – 29°C |
| Hot Water Temperature Range | 30°C – 99°C |
| Primary Use | Water heater (OEM thermostatic management, recirculation) |
HFT40002Z-01 vs HFT40003Z-01 — Opposite Opening Behavior
| Parameter | HFT40002Z-01 | HFT40003Z-01 |
|---|---|---|
| Opens when | Temperature FALLS below threshold | Temperature RISES above threshold |
| Closes when | Temperature RISES above threshold | Temperature FALLS below threshold |
| Use case | Recirculation, low temp detection | Bypass, dump, overheat protection |
| Connection | G1 | G1 |
| Finish | Identical — electroplated connector and handwheel | |
Application & Use Cases
- Hot water recirculation control at G1 capacity – In H-type and similar recirculation systems where the low temperature opening gate valve must handle the larger flow volumes of bigger domestic storage or light commercial installations beyond G1/2 capacity
- OEM water heater thermostatic management at G1 – Water heater manufacturers integrating a low temperature opening valve into G1-connection product lines as part of the heater’s internal thermostatic circuit
- Solar thermal low temperature detection at G1 – Activating a secondary circuit, mixing bypass, or recirculation path when solar collector or storage temperature falls below the defined threshold
- Larger domestic and light commercial systems – Applications requiring the low temperature opening function at G1 (DN25) flow capacity where G1/2 variants are undersized
Installation Notes
- Confirm valve behavior before installation: this valve opens when temperature falls below the set point and closes when temperature rises above it
- Connect supply pipework to the electroplated integrated inlet connector and distribution to the outlet port using appropriate G1 thread sealant
- Position the valve so the thermostatic sensing element contacts the water whose temperature it must sense
- Install isolation valves upstream to enable servicing without system shutdown
- The valve performs optimally at 0.1–0.5 MPa
- For OEM integration dimensional drawings, contact the Legom technical team
Frequently Asked Questions
What is the difference between the HFT40002Z-01 and HFT40003Z-01?
Both are G1 one-way temperature limit valves with identical specs — electroplated handwheel, electroplated integrated inlet connector, 57-3 copper body. The difference is opening behavior: HFT40002Z-01 opens when temperature falls below the threshold (low temperature opening), while HFT40003Z-01 opens when temperature rises above the threshold (high temperature opening). Choose HFT40002Z-01 for recirculation and low temp detection. Choose HFT40003Z-01 for bypass, thermal dump, and overheat protection.
When should I choose the G1 HFT40002Z-01 over the G1/2 HFT33009Z-01?
Both are low temperature opening valves with electroplated finishes. Choose the HFT40002Z-01 (G1/DN25) when the system’s flow demand at the valve installation point exceeds what the G1/2 bore can deliver without excessive pressure drop. Choose the HFT33009Z-01 (G1/2) for compact domestic and single-fixture applications where G1/2 flow capacity is sufficient.
Can the opening temperature threshold be customized?
Yes. The 20–60°C adjustment range allows the threshold to be set across the full range. OEM orders can specify a factory-preset threshold. Contact the Legom team with your specific requirement.
OEM & ODM Customization
Legom supports full OEM and ODM services for the HFT40002Z-01 Open One-Way Temperature Limit Valve. Customization options include temperature threshold, electroplating specification, connection size, and body configuration. Contact us via WhatsApp or info@legomsmart.com.
Product information last reviewed by the Legom Technical Team. For the most current specifications, refer to the official datasheet or contact our sales team.
Custom OEM & ODM Solutions
Legom is a direct manufacturer offering end-to-end OEM and ODM services. With our in-house engineering and production capabilities, we work closely with distributors and system integrators to deliver fully customized solutions under strict NDA.
