Overview
Recovery tank float switch — stainless steel float on a polypropylene barrel, supplied with protector. HydraMaster part number 000-157-0801, listed as Switch, Float S/S Polyprop Barrel w/ Protector and, in later manuals, as Assembly, Float Switch w/ Polypropylene Barrel.
It senses recovery tank level and is what tells the machine to shut down or divert before the tank overflows into the blower.
This is the barrel float. If your machine is fitted with the lever-type Harwil switch instead, order the Harwil Waste Tank Float Switch (SS-69-000S).
What it fits
HydraMaster's suggested spares schedule lists it against five machines, and it is named in the parts lists of:
- HydraMaster Boxxer 318
- HydraMaster Boxxer 318HP
- HydraMaster Boxxer 323HP
- HydraMaster Boxxer 427 — float switch assembly, figure 1-42
- HydraMaster Boxxer XL
- HydraMaster CDS 4.8
- HydraMaster Titan 325
That is seven machines from published parts lists — one of the most widely shared level switches in the range.
The protector is not optional
HydraMaster's own description names the protector as part of the assembly, and there is a reason. A bare float in a recovery tank gets hit by everything the wand picks up and wrapped in everything fibrous. The protector keeps debris off the float so it can travel.
If you find a float switch in service without its protector, that is the fault — not the switch.
HydraMaster's own product service bulletin
HydraMaster issued a low water switch service bulletin covering this area, noting that changing to the improved switch reduces or eliminates false "low water" conditions, and made it standard in new machine production. If your machine is throwing intermittent false low-water alarms, that bulletin is directly relevant. Ask us and we will send you the details for your model.
Diagnosing it
False alarms and no alarms are different problems:
- False "tank full" or "low water" with a tank that is fine — usually a fouled float or barrel, not a failed switch. Clean it first.
- No shutdown when the tank actually fills — this is the serious one. Do not keep running the machine; you are one job away from putting slurry through the blower.
- Intermittent behaviour — check the connections before the switch. A wet tank environment is hard on terminations.
Related parts
- Sidemount Float Switch inc Fittings (157-031) — the side-mount reed switch used in water boxes and mix tanks
- Float Splash Guard Kit (078-357)
Frequently asked questions
Does it come with the protector?
HydraMaster's description is with protector. Ask us to confirm the pack contents before ordering if you need the protector specifically.
Is this the same as the water box float switch?
No. That is 157-031, a side-mount reed switch. This is the recovery tank barrel float.
My machine keeps calling low water. Is the switch faulty?
Clean the float and barrel first, then check the connections. HydraMaster also issued a service bulletin on exactly this symptom — ask us.
Can I run without it?
No. It is what stops the recovery tank overflowing into the blower.
Getting false low-water alarms? Tell us the machine and serial number — there is a HydraMaster service bulletin on this and we will check whether it applies to yours before you buy anything.
