The Caleffi F29571 is a dual-scale temperature gauge reading 32 to 250 deg F (0 to 120 deg C) on a single dial, for Caleffi 280 series ThermoProtec boiler protection mixing valves and 281 series ThermoBloc recirculation and distribution units. It fits the gauge pocket wells cast into the valve body.
Specifications sourced from Caleffi technical brochure 01223/23 NA and ThermoBloc instructions NA10294.03. Last reviewed August 2026.
Key Features
32 to 250 deg F Dual Scale
One dial reads 32 to 250 deg F and 0 to 120 deg C. Dual-scale means a single temperature shown in both units, not two separate measuring points.
Fits ThermoProtec and ThermoBloc
Designed for the gauge pocket wells on Caleffi 280 series ThermoProtec valve bodies and as the replacement gauge for Caleffi 281 series ThermoBloc units, which ship with three.
Verifies Boiler Protection Set Point
Reading bypass from boiler, return from system and mixed to boiler confirms the valve is holding return temperature above the flue gas dew point during commissioning and service.
Front and Rear Pocket Wells
The 280 series body carries pocket wells on both front and rear faces, so gauges can be positioned to suit the installation and read from either side.
Technical Specifications
| Product Type | Dual-scale temperature gauge |
| Application | Boiler protection - non-condensing boilers |
| Series | ThermoProtec 280 / ThermoBloc 281 |
| Scale range | 32 to 250 deg F (0 to 120 deg C) |
| Scale type | dual-scale, Fahrenheit and Celsius on one dial |
| Compatibility | Caleffi 280 series ThermoProtec valves, Caleffi 281 series ThermoBloc units |
| Mounting | gauge pocket well, front or rear of valve body |
Documentation
Related Products
- Caleffi 280165A : ThermoProtec Boiler Protection Mixing Valve 130 F 1" NPT
- Caleffi 280175A : ThermoProtec Boiler Protection Mixing Valve 130 F 1-1/4" NPT
- Caleffi F29634 : ThermoProtec Thermostatic Cartridge 130 F
- Caleffi F29635 : ThermoProtec Thermostatic Cartridge 140 F
Frequently Asked Questions
What is Caleffi F29571 used for?
It is a dual-scale temperature gauge reading 32 to 250 deg F (0 to 120 deg C) on a single dial. It fits the gauge pocket wells on Caleffi 280 series ThermoProtec valves and is the replacement gauge for Caleffi 281 series ThermoBloc units.
Does Caleffi F29571 read supply and return at the same time?
No. It is a single-point gauge with two unit scales on one dial. Reading bypass from boiler, return from system and mixed to boiler requires a separate gauge at each point - a ThermoBloc 281 unit ships with three.
Where does Caleffi F29571 mount on a ThermoProtec valve?
The 280 series body has temperature gauge pocket wells on its front and rear faces. The gauge inserts directly into a well, so no separate tapping or thermowell is required.
What is the warranty on Caleffi F29571?
Caleffi North America covers this product under its two-year limited warranty against defects in material and workmanship from the date of shipment. ZOT Supply is an authorized Caleffi distributor.
- Product Type:
- Temperature Gauge
- Application:
- Boiler Protection
- Series:
- ThermoProtec
- Scale Range:
- 32 to 250 deg F (0 to 120 deg C)
- Compatibility:
- Caleffi 280 and 281 Series
