Overview
Brass compression fitting, 3/16 inch tube × ¼ inch NPT, used to mount the temperature sensing probe into the solution manifold on HydraMaster truckmounts. HydraMaster part number 000-052-587, listed as Compression, 3/16" × 1/4" NPT Thermocouple Fitting.
It is a small brass fitting doing a job that matters: it holds the RTD probe at the right depth in the flow and seals a high-pressure, high-temperature joint around it.
What it fits
Named in the Hi-PSI manifold or by-pass valve assembly of:
- Boxxer 421 — item 19, by-pass valve assembly
- Boxxer 427 — items 11 and 15, Hi-PSI manifold and valve assemblies
- Boxxer 423S — item 1, Hi-PSI manifold assembly
- Boxxer 318
- Boxxer 323HP
- Titan 425
- MAXX 450D / 470D / Diesel — item 17, by-pass valve assembly
It is fitted alongside sensor 149-540 (Sensor, RTD Compression Fitting Style). If you are replacing the sensor, inspect this fitting at the same time.
Fitting advice
Compression fittings are not infinitely reusable. The ferrule deforms permanently onto the probe the first time it is tightened. If you pull the probe out, expect to renew the fitting rather than re-use a ferrule that has already taken a set.
Probe depth matters. Too shallow and the machine reads the manifold rather than the solution, which shows up as temperature that lags or reads low under flow. Set the probe so it sits in the stream before you nip up the ferrule.
Use thread sealant suited to the manifold — check the sealant note on the assembly drawing for your machine. Over-tightening a brass fitting into a brass manifold is a good way to turn a five-minute job into a manifold repair.
Frequently asked questions
Does it include the sensor?
No. The RTD sensor is 149-540, a separate part number. This is the fitting that mounts it.
Can I re-use the old fitting with a new sensor?
Not reliably. The ferrule has already set to the old probe. Renew it.
What size tube does it take?
3/16 inch. The thread into the manifold is ¼ inch NPT.
Is this the same as a thermocouple fitting?
HydraMaster call it a thermocouple fitting in the parts lists, but the sensor it carries on these machines is an RTD. The fitting is the same either way.
My machine is not on the list — will it fit?
Very likely if it has an RTD in the Hi-PSI manifold, but we have only verified the models listed above. Send us your model and serial number and we will check.
Replacing a temperature sensor? Tell us the machine and we will make sure you get the sensor, the fitting and any sealant you need in one go.
