Purpose
Complete bill of materials (BOM) for installing, operating, filling, and maintaining the Navien NCB-E 150 combi boiler selected in Boiler Selection. Serves as the line-item source behind the compressed cost table in that document, and as the master shopping list when the Boiler and Radiant Order is finalized.
Scope: This document lists every component from the gas meter to the manifold supply/return, plus all commissioning chemicals, maintenance consumables, and one-time install tools. It does not cover the PEX manifold or slab loops — those were installed October 2025 and are covered in Radiant Slab Materials Order.
Pre-Install State
Already complete (pre-pour, October 2025):
- ✅ PEX radiant loops embedded in slab; pressurized and tested (see photo: 2025-10-31 - Pixel - Radiant Heating System Pressure Test)
- ✅ PEX manifold installed with supply/return headers, balancing valves, and loop purge valves
- ✅ Slab temperature sensor conduit stubbed up in mechanical closet (see Decisions - Slab Sensor Conduit)
- ✅ Gas, water, electrical service, sewer, and low-voltage conduits stubbed through slab in mechanical closet footprint
Prerequisites before install (see Mechanical Room for sequencing):
- ⏳ Mechanical closet framed and drywalled (Stage 3)
- ⏳ Electrical service energized (licensed electrician pulls 200A through existing conduit)
- ⏳ Natural gas service installed (licensed gas fitter, spring 2026 per Decision - Electrical Now Utilities Spring)
- ⏳ Manual J load calculation confirming NCB-E 150 sizing
1. Boiler & Venting
| Component | Spec / Model | Notes |
|---|---|---|
| Navien NCB-E 150 combi boiler | 150,000 BTU input / 120,000 BTU output, 95% AFUE | Includes internal circulator, small stainless buffer tank, internal DHW expansion tank, and integrated 30 psi pressure relief valve |
| Wall mounting bracket | Ships with boiler | Mount to blocking behind drywall |
| PVC/CPVC intake + exhaust pipe | 2” Schedule 40 | Up to 60 ft equivalent length each per Navien manual |
| Vent termination kit | Concentric or two-pipe, sidewall | Sidewall preferred — avoids roof penetration and flashing complexity |
| PVC primer + cement | Low-VOC, listed for vent use | Purple primer is code-required on most jurisdictions |
| Stainless vent pipe clamps | Secure to wall studs every 4 ft | |
| Bird/insect screens | Often included in termination kit | |
| Fire-stop collar or intumescent sealant | Only if passing through a fire-rated assembly | Mechanical closet wall likely requires this |
Estimated subtotal: 2,200–2,800)
2. Gas Supply (Meter to Boiler)
| Component | Spec / Model | Notes |
|---|---|---|
| Black iron pipe or CSST (yellow jacket) | ¾” minimum for NCB-E 150 | Size per NFPA 54; verify length and fittings don’t derate below required capacity |
| Manual gas shutoff | ¾” ball valve, gas-rated | Within 6 ft of appliance, accessible |
| Sediment trap / drip leg | Tee + 3” nipple + cap below shutoff | Required by code |
| Ground-joint union | Between shutoff and appliance connector | Required by code; allows boiler removal |
| Flex connector (CSST or stainless appliance connector) | ≤6 ft, cannot pass through walls | |
| Yellow gas-rated thread sealant | Gas-rated PTFE tape OR gas-rated pipe dope | Never use white plumber’s PTFE |
| Manometer | Inches-WC, digital (~$40) or borrow | For startup inlet/manifold pressure check |
Estimated subtotal: $60–120 (excluding gas line run, which depends on meter-to-closet distance)
3. Potable Water (DHW Side)
| Component | Spec / Model | Notes |
|---|---|---|
| Cold inlet shutoff | ¾” full-port brass ball valve | Service isolation |
| Hot outlet shutoff | ¾” full-port brass ball valve | Service isolation |
| Sediment filter housing + cartridge | 5-micron pleated, ¾” ports | Protects DHW heat exchanger from debris |
| Water softener | Sized for household draw + garage demand | Strongly recommended for Clare County — hard water is the #1 killer of combi DHW exchangers. Install upstream of boiler on cold inlet |
| Thermostatic mixing valve | Honeywell AM101 or Watts LFL1170, ¾” | Code-required scald protection; set to 120°F on outlet |
| Potable expansion tank | 2-gal, potable-rated (Amtrol ST-5) | Required on closed DHW systems (check valve at meter makes it closed) |
| Dielectric unions | Only if transitioning between copper and galvanized/steel | Prevents galvanic corrosion |
| Boiler drain valves (2×) | ¾” hose-thread | On inlet and outlet for annual descaling |
| ¾” copper Type L or PEX-A | For supply/return runs to fixtures |
Estimated subtotal: 400–900)
4. Hydronic Side (Boiler to PEX Manifold)
The manifold is already installed. This section is the plumbing between the boiler and the existing manifold supply/return headers.
| Component | Spec / Model | Notes |
|---|---|---|
| Isolation + drain “purge” valves (2×) | Webstone Pro-Pal H-53404W or equivalent ¾” | Combine shutoff + drain + flush port in one body. Essential for purging air and service isolation. One on supply, one on return between boiler and manifold |
| Hydronic expansion tank | Amtrol Extrol EX-30 (~4.4 gal) | Sized to slab loop volume. Required in addition to boiler’s internal DHW tank — the internal tank is DHW-only. Mount on return near boiler with a service valve between tank and system |
| Combined air + dirt separator | Caleffi DiscalDirtMag 546 series, ¾” | Removes microbubbles and magnetic debris in one unit. Mount on supply leaving boiler |
| Auto air vent | Float-type | Included with DiscalDirtMag; replace element at 5–10 years |
| Manual air bleeders | Only where piping geometry creates high-point air traps | Usually not needed if air separator is well-placed |
| Pressure-reducing / auto-fill valve | Watts 1156F or Bell & Gossett B7-12 | Maintains 12–15 psi and auto-refills minor losses |
| Backflow preventer | Watts 9D (double-check) or equivalent | Required by MI plumbing code between potable water and closed hydronic loop |
| Feed shutoff | ¾” ball valve on fill line | Isolate the fill line from potable system |
| Pressure + temperature gauge (tridicator) | Optional at manifold | Boiler has built-in; extra gauge at manifold aids diagnostics |
| External circulator pump | Taco 007e or Grundfos UPS15-58 or Alpha 15-55 | Only if Manual J and pump curve analysis show the NCB-E internal pump is inadequate for the slab loop length. Confirm during commissioning |
| Hydraulic separator or closely-spaced tees | Caleffi SEP4 or field-fabricated | Only if adding an external secondary circulator (primary/secondary piping) |
| ¾” or 1” copper + fittings | Type L sweat or ProPress | Size per flow rate from Manual J |
| Pipe insulation | ½” or ¾” wall closed-cell foam sleeves | On all hot supply lines |
| Cushioned pipe hangers | Prevents vibration transmission from boiler pump | |
| Pressure relief discharge pipe | ¾” copper from boiler PRV to within 6” of floor | No valve, no reducer, no cap, no threading at terminus — code requirement |
Estimated subtotal: 100–350)
5. Electrical
| Component | Spec / Model | Notes |
|---|---|---|
| Dedicated 15A/120V circuit | Own breaker at panel | Boiler cannot share circuit |
| 12 AWG Romex or conduit | From panel to boiler junction | |
| Service disconnect switch | Red handle, lockable, within sight of boiler | Code-required emergency shutoff, typically at mechanical closet entrance |
| 4”×4” junction box + cord whip | For boiler power connection | |
| 24V thermostat wire | 18/5 or 18/8 | Boiler to thermostat, plus to zone valves if zoned |
| Thermostat | Ecobee, Nest, or Navien NaviLink | NaviLink adds modulating OpenTherm control and Wi-Fi diagnostics |
| Outdoor reset sensor | Navien-compatible | Strongly recommended for slab efficiency — drops supply water temp as outdoor temp rises |
| Zone control relay | Taco SR-504 or Argo AR-84 | Only if using zone valves instead of multiple circulators |
| Slab temperature sensor | 10K thermistor | Wire to boiler or zone controller via the pre-stubbed conduit |
Estimated subtotal: $100–250 (excluding panel circuit labor)
6. Condensate Handling
| Component | Spec / Model | Notes |
|---|---|---|
| ¾” PVC condensate drain pipe + fittings | Continuous downward slope to drain | |
| Condensate neutralizer kit | JJM CN-1 or Axiom NKIT-1 | Required by MI code for condensing appliances. Raises pH from ~3 to ~7. Limestone media refill every 1–2 years |
| Condensate pump | Little Giant VCMA-15ULS | Only if no gravity drain available. Pumps to sink drain or laundry standpipe |
| Air gap fitting | At drain termination | Prevents backflow from drain into condensate line |
Estimated subtotal: 80–130 (with pump)
7. Controls & Safety
| Component | Spec / Model | Notes |
|---|---|---|
| CO alarm (hardwired) | Mechanical room + loft apartment | MI code requires CO alarms near sleeping areas and within 15 ft of fuel-burning appliances |
| Emergency boiler shutoff (red handle) | At mechanical room entrance | Wired in-line with disconnect; some jurisdictions require remote location |
| ABC fire extinguisher | Mount near mechanical room exit | See Fire Extinguisher Plan |
| Leak detection pucks (recommended) | YoLink, LeakSmart, or Guardian (Elexa) | Place under boiler, manifold, and DHW connections. Provides leak localization — whole-house flow monitors only tell you that water is leaking, not where |
| Whole-house flow monitor + shutoff (house main) | Moen Flo or Phyn Plus | Installed on the house main. The garage is fed from the house supply, so a single unit on the house covers both buildings for bursts. See “Leak Detection Strategy” below |
| Combustible gas detector (optional) | Nest Protect CO/gas combo | Good practice though not code-required for residential |
Estimated subtotal: 100–400)
Leak Detection Strategy
The garage is fed from the house water main, so a Moen Flo (or Phyn Plus) installed on the house side covers both buildings for catastrophic bursts — flow shuts off at the house main regardless of which building the leak is in. Flow monitors can’t tell you where a leak is, so pair the house Flo with wireless leak pucks in the garage mechanical closet (under the boiler, manifold, and water softener connections). Pucks give instant localization via the app so a 3 AM shutoff doesn’t require a cold walk to the garage to diagnose.
Recommended split:
- House: Moen Flo on the main (~$500). Flow-learning catches slow leaks (running toilets, drip leaks, slab leaks) that pucks miss.
- Garage: 2–3 pucks in the mechanical closet (~$60–150 total). Catches the high-probability failures: boiler PRV weeping, expansion tank rupture, manifold/fitting leaks, water softener overflow.
- Manual ¾” ball valve where the garage feed branches off the house supply, so the garage can be isolated without killing house water.
Future: Second Flo for Loft Apartment Conversion
If the loft above is converted to a rental apartment in the future, a dedicated Flo on the garage main becomes worthwhile:
- Independent usage tracking for tenant billing
- Isolated shutoff — a tenant-side leak won’t kill house water
- Flow-learning has enough regular signal to work well once there’s a real occupant
Rough-in accommodation — plan now, install later (near-zero cost):
- Reserve ~10–12” of straight copper (¾” or 1”) on the garage’s incoming water main, inside the mechanical closet, before any branches. Flo needs ~7” straight run for ¾”, ~10” for 1”.
- Place a 120V duplex outlet within 4 ft of that reserved section.
- Install isolation ball valves upstream and downstream of the reserved section during rough-in. Future install becomes a one-hour cut-in with no house-wide shutoff.
- Keep the location accessible — not buried behind the boiler, softener, or wall.
See Mechanical Room for the layout reservation.
8. Initial Fill & Commissioning Chemicals
| Component | Spec / Model | Notes |
|---|---|---|
| System cleaner | Fernox F3 or Rhomar Pro-Tek 922SC | One-time on initial fill — removes flux, pipe oil, and installation debris before adding inhibitor. Circulate 1–7 days then flush completely |
| Corrosion inhibitor | Fernox F1 or Rhomar Pro-Tek 922 | Permanent addition after cleaner flush. ~1% concentration. Protects mixed-metal system (copper, steel, aluminum heat exchanger, brass valves) from galvanic and oxide corrosion |
| Propylene glycol (optional) | Dowfrost HD or Hercules Cryo-Tek 100 | Skip unless freeze risk is real. Garage on continuous heat + power doesn’t need it. Glycol reduces heat transfer ~10% and requires pump derating. Never use automotive ethylene glycol — toxic and wrong chemistry |
| Softened or deionized fill water | — | Hard-water minerals precipitate as scale in the boiler exchanger on first heating cycle. Soft water extends exchanger life significantly |
| Boiler-fill / purge pump | Wayne PC2 or drill-driven pump | Pushes water through each loop to purge air. Connects to purge valve hose bibs |
| Drinking-water-safe garden hose | — | Connects pump to purge valves |
| 5-gallon bucket | — | Purge discharge catch |
| Water test strips | Hardness, pH, inhibitor concentration | Verify before fill (hardness) and after fill (inhibitor level) |
Estimated subtotal: 80–150 per 5-gal if used
9. Maintenance Supplies (Annual / Periodic)
| Component | Frequency | Notes |
|---|---|---|
| Descaling flush kit | Annual | Calefactio SK2500, Rectorseal Calclean, or Fernox MB-1 — submersible pump + two hoses + bucket. Reuses the installed purge valves |
| Descaler solution | Annual | White vinegar is adequate; Fernox DS-40 or Noritz descaler works faster. 3–4 hour circulation through DHW heat exchanger |
| Condensate neutralizer refill media | Every 1–2 years | Limestone chips. Test condensate pH with strip; replace media when pH drops below 5 |
| Sediment filter cartridge | Every 6–12 months | If installed upstream of DHW |
| Inhibitor top-up | Every 3–5 years | Test concentration with Fernox or Rhomar strips; top up after any drain/refill |
| Spare flame sensor | Keep on hand | ~$30, 10-minute swap. Common source of “ignition failure” error codes |
| Spare igniter | Keep on hand | ~$80, 5–10 year service life |
| Spare pressure relief valve | Keep on hand | Cheap insurance — PRVs often weep when old |
| Gasket kit | Keep on hand | For combustion chamber inspection or heat exchanger service |
| Combustion analyzer (optional) | One-time purchase | Testo 310 or UEi C157 (~150/visit |
| Wire brush, stiff nylon brush | Annual | Clean heat exchanger fins from combustion side |
| Vacuum with HEPA + brush attachment | Annual | Intake air inlet and boiler cabinet interior |
Estimated annual maintenance cost: 150 (pro combustion tune-up if not DIY)
10. One-Time Install Tools
Needed for the install but not “components.” Check existing inventory first; see Tool Purchasing Philosophy for buy-vs-rent framework.
- Propane torch + lead-free solder + flux (or Milwaukee M18 ProPress jaws if renting)
- Pipe cutters (½”, ¾”, 1”)
- Deburring tool
- Adjustable wrenches, pipe wrenches (18” minimum)
- Channel locks
- Torque screwdriver (for boiler gas valve and terminal connections)
- Manometer + rubber hose (gas pressure test, inches-WC)
- Multimeter (wiring verification and low-voltage troubleshooting)
- Stud finder (locate blocking for wall-hung mount)
- Level, tape measure, drill + hole saws (for vent penetration — 2½” or 3” hole saw)
- PTFE tape (plumbing) + yellow gas-rated tape
- Soap bubble gas leak test (or electronic gas sniffer)
Estimated Total Component Budget
| Section | Low | High |
|---|---|---|
| Boiler (NCB-E 150) | $2,200 | $2,800 |
| 1. Venting | $80 | $150 |
| 2. Gas supply (excl. run) | $60 | $120 |
| 3. DHW side (excl. softener) | $150 | $350 |
| 4. Hydronic side (excl. external pump) | $150 | $250 |
| 5. Electrical | $100 | $250 |
| 6. Condensate | $30 | $130 |
| 7. Controls & safety | $80 | $200 |
| 8. Initial fill chemicals | $80 | $150 |
| Install subtotal | $2,930 | $4,400 |
| Water softener (if installed) | $400 | $900 |
| Optional external circulator | $100 | $350 |
| Optional glycol charge | $80 | $150 |
| Optional leak detection | $100 | $400 |
| Project total (with options) | $3,610 | $6,200 |
Ongoing maintenance: 350 if purchasing combustion analyzer.
This total aligns with the $2,700–3,600 DIY-installed estimate in Boiler Selection Option 1 when excluding the optional items. The softener is the largest optional line and may be installed separately (not tied to boiler project).
Procurement Strategy
Most items ship from HVAC wholesalers (see HVAC Wholesale Buying Guide) or plumbing supply houses. Consider these sources:
- Navien boiler + Navien-branded accessories: SupplyHouse.com, PexUniverse, or local HVAC wholesaler (contractor pricing often available without a license)
- Caleffi, Webstone, Amtrol hydronic components: SupplyHouse.com, PexUniverse, Menards
- PVC venting, gas components: Home Depot, Lowe’s, local plumbing supply
- Fernox / Rhomar chemicals: SupplyHouse.com, Amazon, or direct from manufacturer
- Condensate neutralizer: Amazon or SupplyHouse.com
Bundle hydronic components in one order to minimize shipping; order venting locally to avoid PVC freight charges.
References
- Boiler selection decision: Boiler Selection
- Mechanical room layout and sequencing: Mechanical Room
- Existing manifold and slab materials: Radiant Slab Materials Order
- HVAC wholesale buying strategy: HVAC Wholesale Buying Guide
- Slab sensor conduit: Decisions - Slab Sensor Conduit
- Utilities and conduit routing: Utilities & Conduits
- Order tracking (to be populated from this BOM): Boiler and Radiant Order
- HVAC strategy (radiant + mini-split system context): HVAC Strategy