Navien NCO series tankless water heater screw size
M4 · 12 mm long
Navien NCO series tankless water heater takes M4 metric screws, 12 mm long.
The record covers service spare part 20041461A screw.
This entry is marked confirmed and comes from midwestsupplyus.com.
For reference, M4 is 4 mm across the threads at 0.7 mm pitch. The imperial size people confuse it with: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same.
Navien NCO series tankless water heater screw specifications
One row per fitment record. Head, drive are shown only where the source states them; pitch is the ISO coarse pitch for the thread.
| Thread | Length | Pitch | Head | Drive | Where it goes | Status |
|---|---|---|---|---|---|---|
| M4 | 12 mm | 0.7 mm | not stated | not stated | Service spare part 20041461A screw | Confirmed |
Fitment records and sources
Service spare part 20041461A screw
pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20
How to check the screw before you buy
- If several screws hold the same part, check that they are all the same length before assuming they are.
- Diameter: across the threads an M4 screw measures about 4 mm with calipers (usually a hair under). If yours measures noticeably more or less, it is a different thread.
- Pitch: 0.7 mm from one thread crest to the next (14.29 crests per centimetre). A thread pitch gauge or the pitch-gauge tool settles it in seconds.
- Length: measure from under the head to the tip for pan, button, wafer and cap heads; countersunk (flat) heads are measured overall.
- The record states 12 mm. Going longer risks bottoming out or touching parts behind the hole; going shorter loses thread engagement.
- Driver: the source does not name the drive. Standard M4 heads take PH2 for Phillips and T20 for Torx, and a 3 mm hex key for socket heads; a bit that fits loosely will cam out and strip the head.
- Tightening: no device-specific torque is published in these records. The site's general figure for M4 is about 2.0-3.0 N·m into metal threads and 0.8-1.4 N·m into plastic bosses; snug it up and stop.
Common mix-ups with M4
- Water heater elements use pipe threads (NPSM/NPT), not metric machine screws.
- M4 and 6-32 UNC share a nominal diameter with different pitch — a classic cross-thread in US-market kits.
Buy these screws at TechSpare Warehouse
In stock and shipped from South Carolina. Our black screws are Phillips wafer head (low profile); match the head style and length to the original before you order.
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- Allen-Bradley PowerFlex 755 IP00 control pod also M4 × 12 mm
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- Star Micronics mPOP under-counter mount (CM-POP1) also M4 × 12 mm
- TEKTELIC Kona Photon Gen-2 LoRaWAN gateway also M4 × 12 mm
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Questions about Navien NCO series tankless water heater screws
- What size screw does Navien NCO series tankless water heater use?
- M4 × 12 mm for service spare part 20041461A screw.
- How long are the screws in Navien NCO series tankless water heater?
- The record gives 12 mm. Measure the original from under the head (overall for a countersunk head) to confirm before ordering.
- What is the thread pitch of an M4 screw?
- 0.7 mm (coarse), which is the standard pitch for M4 machine screws; a 0.5 mm fine pitch exists but is uncommon. The tap drill is 3.3 mm and the normal clearance hole is 4.5 mm.
- What screwdriver do I need for Navien NCO series tankless water heater?
- The sources do not name the drive. For M4, Phillips heads normally take PH2 and Torx heads T20; socket heads take a 3 mm hex key.
- Can I use an imperial screw instead of M4?
- No. Imperial look-alike: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same. Use a true M4 screw so it does not cross-thread or strip the hole.