Quick answer: if a YT28 has weak or unstable flushing, do not compensate by simply opening the water supply further. First verify the water source under flow, the verified water hose and fittings, hose restrictions, the water tube and drill-steel center passage, and then the air-water linkage or injection-valve components. If water is entering the lubrication side of the drill, stop and correct the cause before continuing: excessive water pressure, a damaged water needle/tube, blocked passages, worn seals, or incorrect drill-steel geometry can all contribute.
The current PerfoMax YT28 page confirms a 34–42 mm hole range and an H22 × 108 mm shank. It does not publish one universal water-hose bore, working-water pressure, valve setting, or internal water-part specification. Those items vary with the supplied manufacturer and revision, so the controlled quotation, parts drawing, and model manual must govern service work and replacement selection.
Why Water Flushing Matters on a YT28
A wet-drilling YT28 routes water through an internal flushing path and the hollow drill steel toward the bit. The purpose is to carry cuttings from the hole and help suppress airborne dust. NIOSH notes that wet rock-drilling systems pump water through the drill stem and that flow must be controlled: insufficient water weakens dust and cuttings control, while excessive flow can create operating problems.
That means a water-flushing problem can appear as a drilling-performance problem. A blocked or unstable water circuit may contribute to poor hole cleaning, rising resistance around the drill steel, erratic penetration, and a greater chance that operators misdiagnose the problem as “low impact” or “not enough feed.” Conversely, excessive or misdirected water can enter areas intended for oil-lubricated pneumatic components and create hard starting, contaminated lubricant, corrosion, or reduced drilling speed.
YT28 Water-Flushing Reference Points
| Item | Evidence to verify | Decision it controls |
|---|---|---|
| External water supply | Pressure and flow measured while flushing, not only a static gauge reading | Whether the fault is upstream of the drill or inside the drill/string |
| Hose and fittings | Approved bore, pressure rating, routing, strainer condition and minimum fitting passage | Whether the supply is being restricted before the inlet |
| Water tube/needle | Correct part number, straightness, seal condition and alignment for the exact drill revision | Whether to reuse, replace, or escalate for internal inspection |
| Drill-steel passage | Clear, concentric water passage and undamaged H22 × 108 mm shank end | Whether the rod is loading the tube or restricting flow |
| Bit flushing path | Open ports and water reaching the face under the approved test condition | Whether the restriction is in the bit rather than the machine |
| Working-water setting | Controlled manual/data-sheet limit for the supplied model and revision | Whether the regulator setting is acceptable; never infer a value from another supplier's YT28 |
Symptom-to-Cause Diagnostic Table
| Symptom | Likely Checks | First Action |
|---|---|---|
| Little or no water at the bit | Closed/low source, kinked hose, blocked fitting, blocked water tube, blocked drill-steel passage, linkage/valve fault | Stop drilling, isolate supplies, and verify the circuit from source to bit in sequence. |
| Water starts strong, then fades | Source pressure collapse under flow, filter/valve restriction, hose kink, debris moving in the circuit | Measure/check water delivery while the drill is actually flushing, not only static pressure. |
| Water appears in lubricator/oil side | Water pressure too high, failed seal, damaged water needle/tube, blocked downstream passage | Stop operation and correct the water-injection fault before adding more oil and continuing. |
| Drill becomes hard to start after water issue | Water ingress, over-lubrication/contaminated oil, water needle problem | Isolate the machine, inspect the water-injection components and lubrication condition. |
| Water needle repeatedly breaks | Off-center drill-steel center hole, excessive chuck/bushing clearance, wrong needle length, damaged mating geometry | Do not keep replacing needles without checking drill steel and chuck condition. |
| Flushing is acceptable at collar but poor deeper in the hole | Restricted drill-steel passage, cuttings packing, damaged steel, insufficient delivered water, drilling geometry | Check the full drill string and hole-cleaning path, not only the valve at the machine. |
| Strong water but penetration falls | Water entering lubrication side, excessive water setting, unrelated air/feed/bit problem | Separate flushing condition from air pressure, lubrication, feed and bit-wear diagnosis. |
7-Step YT28 Water-Flushing Troubleshooting Workflow
1. Make the system safe before opening any water component
Shut off and depressurize the air and water supplies before disconnecting hoses, opening valves, or removing the water tube. A pressurized hose or fitting can move unexpectedly. Do not troubleshoot a suspected blockage by placing hands or eyes in front of an outlet.
2. Verify the water source under actual flow
A static gauge can look normal while the supply collapses as soon as water flows. Check that the source valve is fully available, the branch line is not starved by other equipment, and the hose is not flattened or kinked. If the site uses a regulator, confirm its setting against the supplied YT28 manual rather than increasing it until flushing “looks stronger.”
Confirm the approved hose bore and the minimum through-bore of every coupling for the supplied drill. A long run, small adapter, kink, contaminated strainer, or partly closed valve can reduce delivered flow even when source pressure appears adequate.
3. Check the hose, couplings, strainer and connection
Work from upstream to downstream. Look for debris, rust scale, crushed hose sections, damaged seals, partially closed fittings, and small-bore adapters. Clean-water quality matters because the injection mechanism contains small passages that can be restricted by sediment. A repeated “valve problem” may actually be contamination arriving from the site water line.
4. Inspect the water tube/needle and drill-steel center passage
The YT28 manual explicitly warns against operating without the water tube. The tube/needle must feed into the drill-steel water passage without being forced sideways. If the drill steel has an off-center center hole, a damaged shank end, or debris in the passage, the water component can be loaded mechanically instead of simply carrying water.
If a water tube or needle has broken, inspect the cause before fitting another. Check the drill-steel center-hole alignment, shank-end condition, chuck/bushing clearance, controlled tube length, and mating geometry for the exact revision. Repeated breakage is evidence of an unresolved interface or alignment problem, not proof that the tube is merely a consumable.
5. Test the air-water linkage or water-injection valve
If the upstream supply and drill-steel passage are clear but flow still does not respond correctly to the drill controls, inspect the linkage/injection-valve system according to the supplied parts manual. Typical faults include blocked air or water passages, corrosion, a fatigued spring, or damaged sealing elements. Replace parts to the controlled model/revision rather than assuming all “YT28” internals are identical across manufacturers.
6. Check for water backflow into the lubrication side
Water where oil mist should be is a warning condition, not a reason to increase lubricator output. It indicates that the water/air separation path, sealing elements, downstream flushing path, or regulator setting needs inspection. Continuing can dilute or displace lubricant, promote corrosion, and make the drill difficult to start.
After correcting the cause, follow the supplied maintenance procedure to remove accumulated moisture and restore correct lubrication. Do not invent a free-running or purge sequence: the approved shutdown and moisture-removal method for the exact drill controls.
7. Re-test at controlled settings before returning to production
Reconnect the verified components, use the supplier-approved water setting, and confirm that water delivery responds normally through the drill and steel. Then test drilling at low/controlled power before full production. Watch for stable flushing, normal exhaust, normal lubrication film at the shank, and no evidence of water migrating into the air/oil system.
Isolation Proof Matrix: Locate the Restriction Before Replacing Parts
Use this matrix after isolating and depressurizing both supplies. It is a fault-location method, not permission to dismantle a pressurized drill. Internal inspection should be performed only by competent personnel using the correct model manual and parts drawing.
| Controlled check point | Observation to record | What the result proves | Next decision |
|---|---|---|---|
| 1. Site source under flow | Stable or collapsing delivery while the flushing branch is opened | A collapsing supply identifies an upstream capacity, regulator, valve, or branch-demand problem | Correct the site supply before opening the drill |
| 2. Hose/fitting outlet | Clean, stable flow after the full hose and coupling set | Good source but poor outlet flow localizes the restriction to hose, strainer, fitting, or regulator | Clean or replace the verified external restriction |
| 3. Drill inlet and control response | Leakage, delayed response, or no change when the approved control is operated | Good hose delivery with abnormal control response moves the fault boundary into the inlet/linkage/valve group | Stop and use the controlled service procedure |
| 4. Water tube and shank interface | Bent, scored, broken, misaligned, wrong-length, or wet on the wrong side | Physical damage or cross-flow identifies an interface/sealing issue rather than a site-supply shortage | Verify part number, rod geometry, seals, and chuck condition |
| 5. Hollow steel and bit path | Flow reaches the steel but not the bit face, or falls only with a specific steel/bit fitted | The machine can supply water; the restriction is downstream in the rod or bit | Remove the affected tool from service and inspect its passage |
| 6. Exhaust or lubrication side | Water, emulsified lubricant, abnormal mist, or repeated hard starting | Water is reaching a chamber it should not enter, or downstream restriction is forcing cross-flow | Stop work; correct the internal/sealing cause before retest |
Minimum diagnostic record
- drill manufacturer, model, serial/revision, and controlled manual reference;
- water-source type, regulator setting, and pressure/flow observation while flushing;
- hose bore, length, fittings, strainer condition, and photos of routing;
- H22 × 108 mm steel supplier, length, center-passage condition, and bit used;
- the last check point that passed and the first check point that failed;
- where water appeared, whether the symptom occurred free-flushing or in-hole, and whether it repeated with a second verified steel/bit;
- removed-part numbers, damage photos, and the result of the controlled retest.
Why “More Water Pressure” Is Not a Universal Fix
Opening the regulator further helps only when verified delivered water is insufficient and the new setting remains inside the supplied drill's approved envelope. It does not correct a blocked passage, small adapter, bent tube, damaged seal, stuck valve, or mismatched drill steel.
Excessive flow can create operating problems, and water forced into the pneumatic/lubrication path can add a second failure. NIOSH therefore treats flow as a controlled part of wet drilling, not an unlimited cleaning force. Use the model-specific manual and measured flow-path evidence before changing the setting.
The current PerfoMax YT28 product page intentionally does not publish one universal water-pressure guarantee. If a buyer needs a controlled value for mine service-water design or acceptance testing, request it on the quoted data sheet before ordering.
Why the Water Needle Keeps Breaking
A broken water needle/tube is often treated as a consumable failure, but repeated breakage usually deserves a geometry check. The water component must remain aligned with the water passage through the H22 × 108 drill steel. If the drill steel's center passage is off center, the shank is damaged, the chuck/bushing clearance is excessive, or the water component is the wrong length for that revision, each percussion cycle can impose side loading.
For procurement, send the supplier the exact rock-drill model/revision and drill-steel shank specification rather than ordering a water needle by the generic term “YT28 spare.” If the current drill steel is locally made, verify its center-hole geometry and shank-end dimensions against the controlled drawing.
Repeated Water-Needle Breakage: Paired-System Release Test
Do not release a YT28 after repeated water-needle or water-tube breakage on the strength of a new spare alone. The failure can originate in the replacement part, the piston/seat area, front-end clearance, the H22 × 108 shank passage, or the water circuit. Treat these as one matched interface and keep the drill isolated until the checks below establish a defensible cause.
| Release gate | Evidence to capture | Hold condition | Required action |
|---|---|---|---|
| 1. Drill and spare identity | Manufacturer, model, serial/revision, controlled parts list, and the replacement needle/tube part number | The spare is identified only as “YT28,” or its revision and controlled length cannot be verified | HOLD and obtain the correct drawing or supplier confirmation; do not trim or substitute by appearance |
| 2. Failed-part pattern | Break location, bend or scoring direction, number of failures, time-to-failure, and clear photographs | Repeated damage occurs at the same position or on the same side | HOLD the drill and paired steel; repeated directional damage points to unresolved loading or alignment |
| 3. Piston nose and water-component seat | Condition checked against the exact service drawing by competent personnel | Burrs, deformation, eccentric contact, abnormal wear, or an unidentified internal part | REMOVE the damaged component from service and correct the front-end cause before fitting another needle |
| 4. Chuck, bushing and shank support | Cleaned visual inspection and clearance measurement using the model-specific method and limits | Uneven wear, excessive movement, or no controlled acceptance limit | HOLD for measurement or front-end repair; a new needle cannot compensate for poor shank support |
| 5. H22 × 108 steel interface | Shank-end condition, center-passage alignment and depth, passage cleanliness, and comparison with a verified steel | The passage is off center, obstructed, deformed, or contacts the water component during dry fit | REMOVE or segregate the steel; do not force the needle into the passage |
| 6. Water path and setting | Clean source, hose/fitting condition, control response, and the approved measured water setting for this drill revision | Unstable delivery, blocked downstream path, cross-flow, or a setting outside the controlled specification | Correct the water circuit before any powered test |
| 7. Controlled functional test | Verified needle, verified steel and bit, stable flushing, normal lubrication condition, and no new marks after the test | Abnormal noise, leakage, hard starting, water in the air/oil side, new scoring, bending, or repeat fracture | STOP, isolate both supplies, and return to the first failed gate |
Use one-variable comparison, not repeated spare consumption
- Isolate and fully depressurize the air and water systems. Remove the failed part and retain it with the drill and steel identification.
- Inspect the piston/seat, chuck and bushing before installing another water component. Do not use powered rotation or percussion as an inspection aid.
- Dry-check a correctly identified replacement with the suspect steel, following the controlled assembly method. It should not require force or field modification.
- If the result is unclear, repeat the non-powered fit check with one verified H22 × 108 steel while keeping the drill and replacement water component unchanged. This isolates a steel-following fault without changing several variables at once.
- Only after the identity, geometry, support and water-path gates pass should competent personnel perform the model-approved low-risk functional test. Record the result before returning the drill to production.
A comparison can localize the fault, but it does not create a universal dimensional limit. Final acceptance dimensions, clearances and water settings must come from the controlled drawing, parts list or manual for the supplied manufacturer and revision.
Release decision
| Status | Use when | Disposition |
|---|---|---|
| READY FOR SERVICE | All identity and inspection gates pass; the controlled test shows stable flushing, normal lubrication condition and no new contact marks | Release with the completed record and the verified part/steel combination |
| CONDITIONAL CONTROLLED TEST | Static checks pass, but the repaired or replacement interface still requires the exact manual-defined functional confirmation | Restrict to the approved test area and responsible person; do not release to production yet |
| HOLD FOR MEASUREMENT / IDENTIFICATION | A part number, revision, drawing, clearance limit or steel identity is missing | Quarantine the drill, spare and paired steel until evidence is complete |
| REMOVE / RESELECT | A component is damaged, the steel passage is incompatible, the spare is wrong, or the symptom repeats during controlled test | Remove the failed component and correct the root cause before another test |
Copy-ready repeated-breakage record
Drill manufacturer / model / serial-revision: Controlled manual or parts-list reference: Failed needle/tube part number and supplier lot: Failure count and time-to-failure: Break location; bend/scoring direction: Piston nose / seat inspection: Chuck and bushing inspection; measured result and limit source: H22 × 108 steel ID; shank and center-passage evidence: Water source, hose, control response and approved setting: Verified comparison steel/bit used: Static fit result: Controlled functional-test result: Final status: READY / CONDITIONAL TEST / HOLD / REMOVE-RESELECT Photos attached: Inspector / date / approver:
When Weak Flushing Is Actually a Drill-String or Hole-Cleaning Problem
If water exits the machine normally but the bit does not clean the hole, continue the diagnosis downstream. Check the hollow drill steel for internal restriction, the shank passage for deformation, the bit flushing path, and the actual hole condition. Cuttings can pack around the steel in fractured ground, especially when penetration continues after cleaning efficiency has fallen.
Do not use water-flushing diagnosis to ignore other variables. Low penetration can still come from inadequate air at the tool inlet, incorrect feed force, a worn bit, poor lubrication, drill-steel damage, or unsuitable rock/bit matching. For a broader machine diagnosis, see the YT28 rock drill troubleshooting guide. For feed-related symptoms, use the YT28 feed-force and collaring guide.
Daily Wet-Drilling Setup Checklist
- Confirm the water source is clean enough for the drill's small injection passages.
- Check the water hose against the approved bore and pressure rating for the supplied revision; inspect for kinks, crushing, damaged couplings and small-bore adapters.
- Depressurize before opening any water connection.
- Verify the water tube/needle is present, straight and correct for the supplied drill revision.
- Check the H22 × 108 drill steel for a clear, correctly aligned center water passage.
- Confirm the supplier-approved water setting before drilling.
- Test flushing response before full-power collaring.
- Watch for water in the lubrication/exhaust system or an abnormal change in oil condition.
- After operation, follow the manual procedure for removing residual moisture and maintaining lubrication.
What to Send Before an RFQ or Spare-Parts Order
Water-system problems are easier to solve when the supplier receives the actual interface data. Send:
- rock-drill model and manufacturer, not just “YT28”;
- serial number or revision/data-sheet photo if available;
- target hole diameter and typical hole depth;
- H22 × 108 drill-steel supplier, length and water-passage details;
- site water pressure measured while flushing, plus water-source type;
- water hose internal diameter and approximate hose length;
- photos of the water connection, water needle/tube and damaged parts;
- symptom: no flow, weak flow, intermittent flow, backflow, broken needle, or water in lubricant;
- whether the problem appears only while drilling or also during free flushing;
- required spare-parts quantity and whether a controlled parts drawing is needed.
For the current machine configuration, review the PerfoMax YT28 Air-Leg Pneumatic Rock Drill. The current page requires the water connection, hose, supplier and revision to be confirmed before quotation or substitution; use the controlled quotation/data sheet for the final water-service specification.
Frequently Asked Questions
What size water hose does a YT28 use?
Use the hose bore and fitting passage specified for the exact supplied drill, not a generic YT28 number. Record manufacturer, revision, inlet connection, hose length, and the minimum through-bore of every adapter before ordering a replacement.
What water pressure should I use for a YT28?
Use the controlled manual or quoted data sheet for the supplied machine and verify delivery while flushing. Do not transfer a value from another manufacturer's YT28 or increase pressure to overcome an unidentified blockage.
Why is water getting into the YT28 lubricator or air side?
Possible causes include excessive water pressure, a damaged water needle/tube, downstream blockage, seal or injection-valve faults, and incorrect drill-steel geometry. Stop operation, isolate both supplies and diagnose the water circuit before continuing; adding more oil without correcting the water path does not solve the cause.
Why does my YT28 have weak water flow even though source pressure is good?
Static source pressure does not prove delivered flow. Check the hose under flow, fittings and regulators, contamination, the water tube, the H22 drill-steel center passage, and the injection/linkage mechanism. A local restriction can create weak bit flushing while the source gauge still looks normal.
Can I run a YT28 dry if water is unavailable?
The controlled supplier documentation YT28 manual identifies the machine as suitable for wet drilling and states not to operate the tool without a water tube. Site operating rules and the supplied machine manual control the final procedure. Do not convert a wet-drilling setup to dry operation without explicit manufacturer approval and an appropriate dust-control plan.
PerfoMax YT28 System Matching
For a YT28 quotation, PerfoMax treats the drill, air leg, air supply, lubricator, H22 × 108 drill steel and water connection as a matched system. Review the YT28 product page, then send your hole size, rock condition, air supply, water service and drill-steel details for a technical quotation. If compressor delivery is also uncertain, see the YT28 air-compressor sizing guide.
Technical References
- NIOSH — Reducing Hazardous Dust Exposure when Rock Drilling During Construction. Supports wet drilling as a dust-control method, controlled water flow, maintenance, and the warning that excessive flow can cause operating problems.
- UK Health and Safety Executive — Compressed Air Safety (HSG39). Supports suitable hose selection, restraint/venting, accessible isolation, pressure control, and maintenance of pneumatic equipment.