The A-22P-A44 is a Belimo pre-filled syringe of thermal contact paste used to fill the bore of a thermowell before inserting a temperature probe. The paste displaces the air gap between the probe shaft and the well's inner wall, dramatically reducing sensor response time and eliminating the small offset error caused by air-gap insulation. Pre-filled syringe form allows clean, single-handed application directly into the well bore — no transfer from a tube, no mess. Standard for every Belimo thermowell installation.
Required whenever a Belimo 6 mm probe sensor is installed in a thermowell for liquid immersion. Compatible with all Belimo A-22P-A.. thermowells (2", 4", 6", 8", 12", 18" lengths in brass or stainless steel, fabricated or machined). Not needed for duct-mounted sensors with a mounting flange (direct air contact) or for cable sensors used in air without a well.
Key Features
The annular air gap between a 6 mm probe and the well's inner bore acts as a thermal insulator — the probe equilibrates against trapped air, not the well wall. The paste displaces that air, putting the probe in direct thermal contact with the well via conductive medium. Result: faster sensor response (lower time constant) and accurate readings of actual fluid temperature.
Push the syringe nozzle into the well bore, depress the plunger to fill, then insert the sensor probe — excess paste extrudes around the probe shoulder as you push it in. Clean, controlled, no mess. The syringe form is convenient for field installations and service calls where you're on a ladder or in tight mechanical room space.
Each syringe contains enough paste for multiple thermowell fills — exact quantity depends on well length, but a single syringe typically covers several installations. Cap the nozzle between uses to prevent contamination.
Technical Specifications
| Specification | Detail |
|---|---|
| Type | Thermal contact paste, pre-filled syringe |
| Use | Fill thermowell bore before probe insertion |
| Compatible With | All Belimo A-22P-A.. thermowells (6 mm probe bore) |
| Application Form | Single-use syringe, single-handed dispensing |
| Manufacturer | Belimo |
| Manufacturer Part Number | A-22P-A44 |
| Warranty | 5-year factory warranty |
Documentation
Frequently Asked Questions
Do I really need thermal paste in the thermowell?
Strongly recommended for every thermowell installation. The air gap between the probe and the well bore is a thermal insulator — without paste, the sensor response time is longer (typically 9 s vs 7 s for stainless steel wells per Belimo's 01CT datasheet, but the difference grows in real installations) and there's a small static offset. The paste is inexpensive insurance for accurate, fast readings.
How much paste do I need per thermowell?
Fill the well bore from the bottom up — typically 1/3 to 1/2 the well's internal volume. Excess paste extrudes harmlessly around the probe shoulder when you insert the probe. A single syringe of A-22P-A44 typically covers several installations (exact count depends on well length).
Can I use generic thermal paste from another vendor?
Belimo's A-22P-A44 is specifically formulated for HVAC thermowell service temperatures and the materials of Belimo's brass and SS wells. Generic CPU thermal pastes are formulated for different temperature ranges and may degrade or migrate at HVAC water temperatures. Stick with the Belimo paste for warranty and performance assurance.
- Sensor Type:
- Thermal Paste Accessory
- Form:
- Pre-filled syringe
- Use:
- Fill thermowell bore
- Compatible Wells:
- All A-22P-A.. thermowells