Chilled-water hose whip restraint and leak-check photos before CDU startup

Direct answer

Before CDU startup, the chilled-water hose whip restraint and leak-check photo record should identify the CDU, data hall, row, rack manifold, supply and return hose assemblies, hose kit model or tag, coupling type, restraint requirement, restraint type, restraint rating basis, anchor point, slack condition, hose support, bend or kink condition, floor penetration or tile opening, valve lineup, isolation valves, fill and drain points, strainers, filters, air vents, pressure gauges, leak detection sensors, shutoff-valve interlock where used, fill or flush status, leak-check method, test pressure or startup pressure basis where the project requires it, photo IDs, failed conditions, corrections, retests, witnesses, and the exact startup release boundary.

The record should prove that flexible hose assemblies and their safety restraints are installed as the approved documents require before the CDU is energized, filled, circulated, or connected to IT load. A picture of a dry floor does not prove the hose is supported. A hose restraint photo does not prove it is rated, anchored, and installed correctly. A pressure reading does not prove each coupling, valve, drip tray, leak sensor, and return-to-normal alarm path was checked.

Do not invent a universal hose restraint type, restraint spacing, anchor method, hose bend radius, pressure, duration, fill sequence, flush method, glycol mix, corrosion inhibitor, leak-test medium, startup order, or CDU acceptance rule. The manufacturer instructions, approved submittal, design drawings, hose kit instructions, commissioning script, fluid treatment plan, BMS/DCIM point list, owner operations standard, AHJ direction, and site safety plan control those decisions.

Why this gates startup

A CDU moves coolant close to high-value IT equipment. Vertiv's CDU overview describes coolant distribution units as equipment that circulates controlled coolant in a closed loop for direct-to-chip, immersion, and heat-exchanger devices, with pressure, flow, filtration, leak detection, and alarm features used to protect equipment. ASHRAE's data center resources place liquid cooling and data center cooling guidance inside the broader datacom operations context.

Startup is the wrong time to discover that a hose has no support, a quick coupling is not fully seated, a restraint can slide off, a valve is closed, a floor opening has a sharp edge, a leak sensor is not placed, or the wrong row manifold was connected. Vertiv and Trane CDU sources both treat piping installation, leak checking, filling, flushing, fluid quality, valves, pressures, and pre-startup checks as commissioning concerns.

The photo record is not paperwork for its own sake. It lets the commissioning agent, mechanical contractor, liquid-cooling vendor, controls integrator, owner, and operations team see which hoses were ready, which were held, which leak checks passed, and which conditions must be corrected before the CDU can circulate coolant into the white space.

Start with the accepted basis

The first page should name the accepted basis for the startup release. Use the CDU installation and commissioning manual, hose kit submittal, coupling instructions, piping drawings, TCS or FWS design, fluid treatment plan, pre-commissioning cleaning record, pressure-test report, controls matrix, leak detection sequence, BMS or DCIM point list, commissioning script, MOP, and owner turnover checklist.

Vertiv's single-phase technology cooling system guidance is written for flushing, filling, testing, and deployment tasks related to TCS networks, including CDU and TCS installation work such as pipe fitting, leak checking, and electrical wiring. It also identifies hose kits between in-rack manifolds and servers, isolation valves, air vents, strainers, leak sensors, and flushing before IT equipment connection as TCS concerns.

If the record uses an example from a manufacturer manual, keep it tied to that product and project. Trane's CDU manual, for example, gives a startup-test pressure range in its own filling procedure. That is useful evidence that a field record should capture the project pressure basis; it is not a pressure rule for every CDU or hose assembly.

Define the release boundary

A CDU startup release can cover different scopes. It may release facility-water-side fill only, TCS flush only, secondary loop fill, pump bump, low-speed circulation, leak-check hold, BMS point test, dry functional test, or full CDU startup with connected rack manifolds. The record should state which one is being released.

Separate facility water system, technology cooling system, CDU internal circuit, row manifold, in-rack manifold, rear-door heat exchanger, cold-plate circuit, temporary fill hose, permanent hose kit, and drain hose evidence. One clean fill hose does not prove the permanent rack hose. One CDU base leak sensor does not prove the row manifold. One dry manifold photo does not prove the hose at the rack end.

If the release is partial, say so. Examples include CDU ready for fill but held from pump start, secondary circuit flushed but not connected to IT equipment, Row C released except Rack C18 supply hose, local leak sensor tested but BMS shutoff point held, or temporary fill hose allowed only under vendor supervision.

Map hoses before photographing

Start with a hose map that names each supply and return hose assembly. Record CDU port, row manifold port, rack manifold port, rear-door or cold-plate connection, flow direction, hose tag, hose length where known, coupling type, isolation valve, fill point, drain point, sensor location, restraint location, anchor point, and the photograph IDs that prove the condition.

Coolcentric's commissioning service description identifies tasks such as attaching quick-coupling hose assemblies to rear-door heat exchangers, attaching quick-coupling hose assemblies to CDUs or manifolds at supply ends, and securing hose assemblies to stringer, hanger, or floor as specified in the site schedule. That is the level of location detail a startup record should preserve.

A useful photo packet follows the hose from source to load and back. Do not photograph only the easy end. Include the floor penetration, under-floor route, support, rack end, CDU end, valve tag, coupling collar, restraint, anchor, and any drip tray or leak sensor.

Record support and restraint

For each hose, record the support method and the restraint requirement separately. Support keeps the hose routed, elevated, protected, and strain-relieved. A whip restraint or hose safety restraint is intended to limit hose travel if a pressurized hose separates or fails. One does not automatically substitute for the other.

Vertiv's XDU1350 pre-commissioning checks call for confirming that bottom-exit pipework, manifolds, and hoses have required floor-tile openings with brush-strip grommets where applicable, and that cable baskets, cable trays, drip trays, or similar supports have been installed to provide adequate support for hoses. Hose-restraint sources from Capital Rubber and Chicago Coupling emphasize correct matching, installation, inspection, slack control, anchoring, and replacement after a failure event.

Photograph the restraint tag or rating label where present, the hose outside diameter fit, the collar or loop, the anchor point, the shackle or hardware, slack, and the direction of possible hose travel. If the approved design does not require a whip restraint for a particular hose, write the basis rather than inventing one in the field.

Check couplings, valves, and labels

Couplings and valves should be checked before the first startup release. Record whether quick couplings are fully seated, locked, capped before connection, clean, undamaged, correctly oriented, and matched to the approved hose kit. Record valve tags, supply and return labels, normal position, lock or handle position, drain and vent status, strainer status, and whether isolation valves are installed where the design requires them.

Vertiv's TCS deployment guide identifies isolation valves at the CDU and at supply and return connections, air vents to remove air from the cooling loop, strainers to protect IT equipment, and external leak sensor placement along or below secondary row manifolds. Trane's CDU IOM records FWS and TCS piping connection, fill points, drain points, strainers, vent valves, pressure sensors, and a pre-startup checklist.

Photo labels should match the controls and piping names. A hose tagged Row 4 Supply in the field but entered as Row 3 Return in the startup record is not ready. Preserve the mismatch as an exception and retest after correction.

Prove fill, flush, and air management

The startup packet should include the accepted fill and flush status. Record whether the CDU arrived factory flushed, whether project flushing was required, whether the TCS was flushed before IT connection, whether filters or strainers were installed, whether fill fluid was labeled, whether air vents were present at high points, and whether bleed points were opened under the approved procedure.

Vertiv's TCS deployment guide says third-party equipment should be cleaned and flushed before installation into the TCS, warns about contamination in construction environments, and describes filling and flushing as part of deployment. Vertiv's CoolPhase manual describes filling and flushing the secondary fluid circuit and, for initial startup, planning filtration, bypass, load banks, and leak detection. Coolcentric lists filling CDU reservoirs, releasing air from bleed points, checking fluid condition, and adding treated make-up fluid as commissioning activities.

Do not use a hose photo to stand in for water-quality evidence. If the project requires fluid sample results, inhibitor concentration, biocide, glycol concentration, particulate cleanliness, conductivity, pH, or a vendor flush certificate, attach or reference that evidence separately.

Leak-check evidence needs locations

A useful leak-check record identifies each location checked, the method, the pressure or operating state used, the time observed, the person checking, the result, and the photo. Locations include CDU primary connections, CDU secondary connections, fill hose, drain hose, hose-to-CDU couplings, hose-to-manifold couplings, rack-end couplings, valves, strainers, vents, filters, pump seals where visible, drip trays, low points, and leak sensors.

Vertiv's CoolPhase guide says to check the cooling fluid system for leaks before commissioning and to inspect fluid pipe connections to the heat exchanger. Trane's pre-startup checklist includes confirming the CDU is filled with coolant and that there are no system leaks. Vertiv XDU material warns that chilled-water line leaks can damage equipment and recommends monitored leak detection for the unit and supply and return lines.

Photograph both dry conditions and failed conditions. A leak that was wiped up without a failed-condition photo becomes a dispute later. Record the correction, cleanup, retest method, and retest result before startup release.

Verify leak detection and shutoff points

For startup, leak detection and shutoff evidence should be separate from hose photos. Record leak sensor location, drip pan or under-unit sensor, row manifold sensor, alarm point, BMS or DCIM message, shutoff valve command where used, local alarm, reset, returned-to-normal status, and any bypass or manual watch.

Vertiv CDU manuals repeatedly recommend monitored fluid detection equipment and, where applicable, automatic closure of field-installed coolant-fluid supply and return shutoff valves to reduce leakage and equipment or building damage. Vertiv's TCS guide also identifies external fluid leak sensor detection devices along or below the secondary row manifold.

Do not claim automatic protection unless it was tested or accepted by the commissioning basis. A visible leak rope, a normal controller screen, and a valve actuator photo are three different pieces of evidence. The record should say which path was proven.

Pressure and startup readings

Record pressures, flow, temperatures, and pump status only against the approved basis. Useful fields include static fill pressure, startup test pressure where required, supply pressure, return pressure, differential pressure, pump speed or command, strainer differential pressure, valve position, temperature, dew point or condensation-control status where applicable, and the source of each reading.

Vertiv's CDU overview explains that CDUs manage temperature, pressure, and flow rate in an isolated secondary loop. Vertiv XDU guidance calls for verifying discharge and suction pressures during startup to confirm pump direction. Trane's CDU filling procedure gives a startup-test pressure range for its product and says initial startup is performed under the stated commissioning process.

Do not use a pressure number as a pass without context. The packet should identify the gauge or sensor, calibration or acceptance basis where required, reading time, allowed range, who accepted it, and what equipment was connected when the reading was taken.

Use an auditable table

Use the owner form, commissioning script, vendor startup sheet, hose kit checklist, or controls point-to-point sheet first. Add a field table where the required forms do not connect hose restraints, leak checks, photos, alarms, exceptions, and release boundaries.

Build the photo packet

The photo packet should include the CDU nameplate, CDU ports, hose tags, supply and return labels, row manifold, rack manifold, quick couplings, valve handles, drain and fill points, air vents, strainers, filters, floor openings, grommets, supports, restraints, anchor points, drip trays, leak sensors, BMS or DCIM alarm screen, pressure readings, and failed-condition corrections.

Use repeated angles. Take one wide photo that locates the row or rack and one close photo that proves the connection, restraint, label, or leak-check point. For under-floor routes, photograph the tile grid or row label with the open tile so the reviewer can locate the condition after the floor is closed.

Tie each photo to the checklist. A file named CDU hose is weak. A caption such as CDU-2 secondary supply Hose H-2S at Row D manifold, restraint WR-2S anchored to stringer, no slack, no leak at 35 minutes is usable because it connects equipment, condition, and time.

Exceptions and retests

Failed conditions should stay in the packet. Record the failed condition, location, expected requirement, actual condition, responsible party, correction, retest method, retest result, photo IDs, and release decision.

Common startup holds include a missing restraint, restraint with slack, restraint anchored to a movable item, restraint that can slide off, unsupported hose, kinked hose, hose rubbing a sharp tile edge, wrong supply/return label, quick coupling not fully seated, closed isolation valve, open drain, missing strainer, dirty fill hose, unverified flush, leak at a coupling, leak sensor not reporting, shutoff valve not responding, or pressure reading outside the accepted basis.

If the owner accepts a temporary condition, write the exact limit. Examples include vendor-supervised fill only, local watch required at Row B manifold, pump start held above low speed, CDU started without IT load, or Row 5 held until replacement hose arrives.

Before CDU startup checklist

Run this check before representing chilled-water hose restraints and leak checks as ready for CDU startup.

• Confirm the release scope: CDU, data hall, row, rack range, circuit side, fill, flush, pump start, leak-check hold, connected load, and excluded areas.
• Confirm the accepted basis: CDU manual, hose kit submittal, piping drawings, controls matrix, commissioning script, MOP, fluid treatment plan, pressure-test report, and owner requirement.
• Map each hose assembly: supply or return, hose tag, model, length where known, coupling type, CDU port, row manifold, rack manifold, flow direction, and photo ID.
• Check support: tray, hanger, stringer, floor support, tile opening, brush or grommet protection, strain relief, bend, kink, abrasion, and sharp-edge clearance.
• Check restraint: required basis, type, fit, rating tag, pressure or application basis, anchor, shackle, slack, direction of possible travel, inspection date, and photo ID.
• Check couplings and valves: seated and locked couplings, caps removed or installed as appropriate, valve tags, normal positions, isolation valves, drains, vents, fill points, strainers, and filters.
• Verify fill and flush evidence: flush record, clean fill station, labeled fluid containers, fluid treatment report where required, filters, strainers, air vents, bleed points, and make-up fluid.
• Perform the approved leak check at each CDU, hose, manifold, valve, strainer, vent, fill, drain, rack, and sensor location; record method, pressure or operating state, time, result, and photos.
• Verify leak detection and shutoff behavior where required: sensor location, local alarm, BMS/DCIM point, shutoff valve command, reset, returned-to-normal status, and any bypass.
• Record startup readings against the approved basis: static pressure, supply and return pressure, differential pressure, flow, temperature, pump status, valve position, and reading source.
• Document every exception, correction, retest, temporary watch, conditional release, pending sample, missing tag, failed alarm, or held rack.
• State the decision: released for fill, released for pump start, released for low-speed circulation, released for connected load, released with condition, held for correction, or retest required.

Weak and strong records

Weak note: CDU hoses checked. No leaks. Ready to start.

That note does not identify the CDU, hoses, support, restraints, couplings, valve lineup, fluid basis, pressure state, leak detection, photos, exceptions, or startup boundary.

Stronger note: CDU-3 secondary loop startup review completed for Data Hall 4 Rows E through H on 2026-06-09 under Vertiv XDU submittal XDU3-REV6, hose kit HK-DH4-02, TCS flushing record TCS-FL-019, fluid report FR-44, commissioning script CX-LC-12, and owner MOP LC-003. Release scope is fill and low-speed pump circulation with no IT load connected. Rows E and F are included. Rows G and H remain held pending rack manifold completion.

The hose map identifies eight supply and eight return hose assemblies between CDU-3 and Row E/F manifolds. Photos H-01 through H-20 show CDU secondary ports, hose tags, quick couplings seated and locked, valve lineup, floor openings with brush grommets, hose support on tray, and restraints WR-E1 through WR-F4 anchored to fixed stringers with no visible slack. Hose H-F2 return was found rubbing the tile edge at grid F14. The hose was rerouted, edge protection was added, and photos H-31 through H-33 show the correction.

Leak check LC-3 was performed at CDU ports, hose couplings, manifold couplings, drains, vents, strainers, and drip tray locations under the startup pressure basis in CX-LC-12. No leaks were observed after the required hold. Leak sensor LDS-DH4-ROWF reported locally and at BMS point LC-DH4-F-LEAK, then reset and returned to normal. Shutoff command was accepted for local functional verification only; full BMS interlock remains held under issue LC-027. CDU-3 is released for fill and low-speed circulation for Rows E and F only. Connected IT load and Rows G/H remain held.

The stronger note works because it names the basis, maps the hoses, proves restraint and support, records failed and corrected conditions, separates local leak detection from BMS interlock status, and states the release boundary.

Common mistakes

The first mistake is using a dry-floor photo as a leak-check record. The record needs locations, method, pressure or operating state, time, and result.

The second mistake is treating support and whip restraint as the same thing. Support controls routing and strain. Restraint controls hose travel during a failure event where required.

The third mistake is photographing only one hose end. CDU-end, manifold-end, rack-end, support, restraint, anchor, floor opening, and sensor locations all matter.

The fourth mistake is accepting a restraint without rating or fit evidence. A loose restraint, wrong anchor, too much slack, or sliding loop can create a false sense of protection.

The fifth mistake is skipping leak detection and shutoff verification. A dry hose does not prove the owner will see a leak alarm or that an automatic shutoff sequence works.

The sixth mistake is using the startup packet as design approval, pressure-test approval, fluid acceptance, or white-space turnover. Keep the release scope narrow.

Questions that come up

Does every CDU hose need a whip restraint? Use the approved design, manufacturer instructions, safety plan, and hose-restraint risk assessment. If restraints are not required for a hose, the record should state that basis. If they are required, the record should prove fit, rating, anchor, slack, and condition.

Can a hose be started up with a small seep? No startup release should hide an active leak. Follow the manufacturer and commissioning procedure, correct the condition, clean the area, retest, and preserve the failed-condition record.

What pressure should be used for the leak check? Use the project requirement, manufacturer procedure, commissioning script, and approved test report. Do not copy pressure values from another product manual unless that manual controls the installed equipment.

Should leak sensors be tested before startup? If the project uses leak detection or shutoff interlocks as part of startup readiness, the record should show the sensor, point, alarm path, reset, returned-to-normal status, and any held interlock.

Who signs the record? Follow the contract. Signers may include the mechanical contractor, liquid-cooling vendor, CDU manufacturer representative, commissioning agent, controls integrator, owner operations lead, facility engineer, safety representative, and AHJ where applicable.

Compliance and safety limits

This field note is not a CDU design, hose selection, hose restraint selection, pressure-test procedure, fluid treatment specification, startup procedure, lockout/tagout procedure, BMS/DCIM sequence, leak detection design, shutoff-valve design, fire-code interpretation, white-space acceptance, or owner operations procedure. The approved project documents, manufacturer instructions, commissioning authority, engineer, owner, AHJ, qualified liquid-cooling vendor, mechanical contractor, controls team, and site safety plan control the work.

Do not use this checklist to bypass pressure safety, stored-energy controls, pump safety, electrical safety, lockout/tagout, hot-work limits, chemical or glycol handling, spill response, floor-tile handling, access control, alarm bypass approval, PPE, qualified-person requirements, or emergency procedures. The packet preserves hose restraint and leak-check evidence before CDU startup. It does not authorize unsafe startup or unapproved operation.

Sources checked

• ASHRAE, Data Center ResourcesUsed for official data center cooling, liquid cooling, humidity, energy, and technology-space operations context.
• Vertiv, Understanding Coolant Distribution Units for Liquid CoolingUsed for CDU function, closed-loop coolant, FWS/TCS separation, pressure, flow, dew point, filtration, leak detection, and alarm context.
• Vertiv, Liebert XDU1350 Coolant Distribution Unit Installation and Commissioning GuideUsed for pre-commissioning checks, hose support, tile openings, grommets, leak detection, shutoff valves, filling, flushing, valves, and startup pressure-reading context.
• Vertiv, CoolPhase CDU Installer/User GuideUsed for CoolPhase CDU startup, secondary circuit filling/flushing, leak checks before commissioning, leak detection, shutoff valves, and post-startup checks.
• Vertiv, Guidelines for Deployment of Single Phase Technology Cooling SystemUsed for TCS deployment, hose kits, manifolds, flushing, filling, leak checking, isolation valves, air vents, strainers, leak sensors, and coolant quality context.
• Trane Technologies, Coolant Distribution Unit Installation Operation and MaintenanceUsed for CDU piping, FWS/TCS connections, filling procedure, fill points, valves, startup-test pressure example for that product, and pre-startup no-leak checklist context.
• Coolcentric, Data Center Cooling Installation and CommissioningUsed for practical commissioning context around filling CDU reservoirs, releasing air from bleed points, checking fluid condition, attaching quick-coupling hoses, securing hose assemblies, and logging CDU data.
• Capital Rubber, Hose Safety Whip RestraintsUsed for hose safety restraint selection, fit, installation, no-slack guidance, anchor context, regular inspection, and replacement after a failure event.
• Chicago Coupling, Hose Safety Restraint Types and SelectionUsed for matched restraint selection, pressure rating tags, minimizing hose travel, anchoring, slack limits, inspection, replacement, and the limit that restraints do not remove all risk.

Related guides