The Caleffi 521333A is a TubMixer thermostatic mixing valve, listed to ASSE 1070. It is used for point of use temperature control in domestic hot water and hydronic systems.
Best for fixture-level installation where delivered temperature must be limited at the tub, shower or lavatory to prevent scalding.
Specifications sourced from Caleffi NA technical literature, 2025 revisions.
Key Features
ASSE 1070 Anti-Scald
Certified point-of-use protection, limiting delivered temperature at the fixture to guard against scalding.
Thermostatic Element Control
A wax-actuated element responds to outlet temperature changes and repositions the shuttle continuously, holding setpoint without power or controls.
Low-Lead Brass Construction
Wetted surfaces carry a weighted average lead content below 0.25%, meeting Section 1417 of the Safe Drinking Water Act.
Technical Specifications
| Connection Size | 3/8" |
| Maximum operating pressure | 150 psi |
| Adjustment temperature range | 85 - 120 deg F |
| Maximum inlet temperature | 185 deg F |
| Flow rate working range | 0.5 - 9 gpm |
| Material | DZR low lead brass |
| Certification | ASSE 1070 |
| Series | TubMixer |
| Valve Technology | Thermostatic |
| Shipping Weight | 1.6 lb (approx.) |
Documentation
Design Resources
Related Products
- Caleffi 521333A 002 : TubMixer Thermostatic Mixing Valve 3/8" Compression
- Caleffi 521301A : TubMixer Thermostatic Mixing Valve
- Caleffi 521342A : TubMixer Thermostatic Mixing Valve 1/2"
- Caleffi 521342A 002 : TubMixer Thermostatic Mixing Valve 1/2" NPT
Frequently Asked Questions
Does Caleffi 521333A provide scald protection?
Yes. Caleffi 521333A is listed to ASSE 1070, which governs water temperature limiting devices installed at the point of use. It limits delivered temperature at the fixture and is intended to work downstream of a distribution-level mixing valve, not to replace one.
What is the temperature adjustment range of Caleffi 521333A?
The adjustment temperature range is 85 - 120 deg F. Maximum inlet temperature is 185 deg F. Confirm the setpoint against the applicable plumbing code for the installation.
Does Caleffi 521333A include integral check valves?
No. This model is supplied without integral inlet check valves. Caleffi offers a companion model with a C in the product code for applications that require built-in crossflow protection.
What is the warranty on Caleffi 521333A?
Caleffi covers this product under its standard two-year limited warranty against defects in material and workmanship from the date of purchase. ZOT Supply is an authorized Caleffi distributor.
- Product Series:
- TubMixer
- Valve Technology:
- Thermostatic
- Application:
- Point of Use
- Connection Size:
- 3/8 inch
- ASSE Listing:
- ASSE 1070
- Integral Check Valves:
- No
- Temperature Gauge:
- No
- Adjustment Temperature Range:
- 85 - 120 deg F
- Body Material:
- DZR low lead brass