Filter Elements — Quick Reference (English)

Items: HT718-00-CRN· HC645-01-C

1) HT718-00-CRN— Return / Low-Pressure Canister Element

What it is

A disposable pleated filter element installed inside a pipe-mounted canister on a hydraulic or lubrication return line. The head will have a flow arrow stamped on it — oil enters the pleats from outside and exits through the centre.

• HT718 = housing family and size class (fixes OD, height, centre-tube dimensions)

  
  

• 00 = standard configuration (no drain cock / heater / magnet unless the specific head casting has them)

  
  

• CRN = seal / option package — the C portion points to NBR (Buna-N), black or dark grey O-ring, suitable for mineral hydraulic oil (HLP/HM). The RN portion is a variant marker (often relates to bypass spring or end-cap detail) — treat it as "part of the identity, do not drop when reordering."

  
  

What to check before fitting

1. Read the filter head nameplate near the ports: model should contain HT718…, plus pressure rating (bar) and port size.

   
   

2. Confirm the flow arrow on the head matches pipe direction.

   
   

3. Ruler-check the new element against the old one: height / OD / centre-hole must match.

   
   

4. O-ring colour should be black/dark grey (NBR). If the old one was brown/red, stop — you may need the Viton variant, not "CRN."

   
   

Replacement — safe sequence

1. Stop pump → open vent/bleed until pressure reads zero.

   
   

2. Support the bowl (don’t let it hang on piping) → release clamp/retainer.

   
   

3. Pull element straight out — no prying against pleats.

   
   

4. Check bowl bottom for bright metal shavings (pump/gear wear warning).

   
   

5. Wipe sealing face → thin film of clean hydraulic oil on O-ring (no grease, no sealant).

   
   

6. Seat element square on centre support tube → close vent slowly → ΔP indicator green, no seep.

   
   

Procurement wording (safe)

“HT718-00-CRN — element for HT718-family housing only; confirm against head nameplate; require supplier to state OD / height / centre bore / seal compound before delivery — keep the 'CRN' suffix exactly as specified, no 'similar size' substitute.”

2) HC645-01-C— Air / Gas Coalescer-Separator Cartridge

What it is

A coalescing/separator cartridge used to remove liquid droplets (oil mist, water) and fine particles from a compressed-air or gas stream. It lives in a dedicated separator vessel, not a hydraulic oil return canister.

• HC645 = coalescer housing family and size class

  
  

• 01 = length/size index (fixes OD and overall length)

  
  

• C = NBR seal (black/dark grey), standard for general air-service duty

  
  

⚠️ Do not confuse this with HC645-1-CWB(wing-bolt closure) — the -01-C here uses the standard closure (clamp/nut, tool needed). The cartridge itself is the same filtration media; only the bowl latch differs.

What to check before fitting

• Housing nameplate/tag: model HC645…, max working pressure (bar/psi), temperature range, port size.

  
  

• Flow direction: gas normally enters the side, passes through/around the media, clean gas exits the top (follow the arrow on the head/bowl — reversal kills separation).

  
  

• Old cartridge: note OD / length / centre stud style and whether the bowl uses wing-bolt (WB) or standard clamp — match the new cartridge to the existing bowl latch type, not just the media size.

  
  

Replacement steps

1. Isolate the filter → open the drain cock first (these vessels accumulate liquid — relieve pressure slowly through the drain so it doesn't spray).

   
   

2. Confirm pressure = 0 on the local gauge.

   
   

3. Open the closure (standard clamp/nut for -01-C) → withdraw cartridge straight, protect the outer media wrap.

   
   

4. Check housing interior for standing water/sludge (tells you if the separator is overloaded or the auto-drain failed).

   
   

5. Thin compatible lubricant on O-ring → seat cartridge centred on the stud/tube.

   
   

6. Re-close → close drain → repressurise gradually (crack the inlet valve slowly — brief foaming/pop is normal as trapped liquid clears).

   
   

7. Confirm auto-drain operates if fitted, and no condensate/air leaks at bowl seam.

   
   

Procurement wording (safe)

“HC645-01-C — coalescer/separator cartridge for HC645-family vessel (standard closure, not wing-bolt). Confirm length / OD / centre stud style / seal (NBR) against housing nameplate before delivery.”

3) One-Line BOM (copy-paste)

• HT718-00-CRN— Return/lube canister element, NBR seal (C), HT718 housing per head nameplate only

  
  

• HC645-01-C— Air/gas coalescer cartridge, NBR seal (C), HC645 housing (standard closure, not wing-bolt) per nameplate

  
  

Field rule to remember

• HT718 = "keep particles out of the tank" → treat like any hydraulic return element.

  
  

• HC645 = "knock droplets out of the gas" → always drain first, repressurise slowly, and never flip the flow arrow.

  
  

• If the two sit on the same skid, the bowl closure type (wing-bolt vs standard) is the easiest "don't grab the wrong box" check — -CWBvs -01-Clook alike on paper but the bowl latch won't match if you swap them.