nti boiler install, Service & Repair – Marin & Sonoma County
Local Plumbing — The North Bay’s NTI boiler Specialists
Local Plumbing is the leading NTI boiler installer and service provider in the North Bay. Over the last 24 months, we’ve installed more than 50 NTI TRX systems across Marin, Sonoma, and Napa — making NTI our go-to choice for high-efficiency hydronic and radiant heating systems.
If you want quiet operation, incredible modulation, long-term reliability, and a boiler that pairs perfectly with radiant floors, the NTI TRX is one of the best systems available today.
We install, service, and repair every model in the NTI lineup:
TRX • TFT • FTVN • FTG • S20W • Combi TRX models

Why Local Plumbing Recommends NTI Boilers
✔ Extremely quiet — ideal for tight mechanical rooms
NTI systems run quieter than most competing boilers.
✔ Excellent modulation ratios
This means smoother heat output, less cycling, and lower gas usage.
✔ Incredible reliability in radiant homes
Perfect for Mill Valley, Tiburon, Fairfax, and Petaluma radiant slab systems.
✔ Easy to service
NTI’s design makes maintenance predictable, clean, and efficient.
✔ Smart controls & outdoor reset
Better comfort and better efficiency during North Bay temperature swings.
✔ Stainless steel heat exchanger
High efficiency and long lifespan with proper maintenance.
Local Plumbing installs more NTI boilers than any other brand because our technicians trust them in the field — especially with the radiant heating systems common in Marin and Sonoma. Our data backs up the quality of the unit, with Local Plumbing offering a 3 year labor warranty as standard on most installation situations.
North Bay Homes Where NTI Boilers Work Best
NTI TRX and TFT systems are ideal for:
- Radiant floor heating homes
- Multi-zone hydronic systems
- Large homes with high heat demand
- Homes replacing old cast-iron boilers
- Homes upgrading from older Navien/HTP/Lochinvar units
- Hill or coastal homes with exterior venting challenges
- High-end remodels or additions
If you want reliable heat and consistent hot water, NTI is one of the strongest brands available.
NTI Models We Install
NTI TRX Series (Our Top Recommendation)
Your best all-around boiler for radiant heat, baseboard, high-efficiency heating, and combi applications.
Common local installs:
- TRX 120
- TRX 150
- TRX 199
NTI TFT Series
High-output, floor-standing or wall-hung boilers for large hydronic systems.
NTI FTVN Series
A great option for smaller homes with hydronic heat.
NTI TRX Combi
Perfect for ADUs, remodels, smaller homes, or any property needing heat + hot water from a single high-efficiency boiler.
NTI Boiler Installation with Local Plumbing
Every NTI boiler installation includes:
- Full system sizing and heat load calculations
- Removal and disposal of old boiler
- Primary/secondary piping with low-loss header or closely spaced tees
- New ECM circulator pumps
- Radiant manifold setup or rebuild if needed
- Thermostat, zoning, and control setup
- New venting system (PVC, CPVC, or polypropylene)
- Gas line sizing verification
- Startup, tuning, and commissioning
- Homeowner walkthrough on operation and maintenance
All installations are performed to manufacturer specifications to protect your NTI warranty.
NTI Boiler Service & Maintenance
Annual service keeps NTI boilers operating safely and efficiently.
Our NTI service includes:
- Combustion analysis
- Cleaning flame rod, igniter, and burner
- Checking condensate trap and drains
- Flushing heat exchanger when needed
- Testing fan, spark, sensors, and safeties
- Inspecting and bleeding radiant zones
- Verifying system pressure & expansion tank
- Checking outdoor reset operation
- Updating control settings for optimal performance
Most NTI boiler breakdowns happen because the system hasn’t been serviced — especially in radiant homes where air buildup is common.
NTI Boiler Repairs
We repair every NTI model.
Common problems we fix:
- No-heat / boiler not firing
- Ignition failure
- Flow errors
- Air in radiant loops
- Stuck or failing pumps
- Low-loss header issues
- Fan errors
- TRX lockout codes
- Leaking relief valves
- Sensor and thermistor failures
- Control board issues
- Cycling on/off repeatedly
If your NTI boiler is throwing codes or shutting off, we can diagnose and repair it quickly.
Real NTI Jobs Completed by Local Plumbing
Mill Valley – NTI TRX 150 Installation
Replaced aging cast-iron boiler
Installed new TRX system + ECM pump + radiant manifold upgrades
Total: $15,400
Tiburon – NTI TRX Combi Replacement
Removed tank water heater + old boiler
Installed TRX combi for heat + hot water
Result: Faster hot water, quieter system
Total: $12,800
San Rafael – NTI TRX No Heat
Cause: Failed thermistor + air in system
Fix: Replaced sensor, purged radiant zones
Total: $420
Petaluma – NTI TFT Install for Radiant Home
Installed new TFT series boiler + low-loss header
Total: $17,900
NTI Boiler Pricing**
- NTI TRX installation: $12,500 – $17,500
- TRX Combi installation: $14,000 – $18,000
- TFT installation: $12,000 – $22,000
- Annual NTI service: $950 – $1550
- NTI TRX repairs: $350 – $1050
- Radiant system purge: $450 – $900
We provide upfront, written estimates with no surprises. **Pricing varies depending on complexity of the job.
Service Areas
We install and service NTI boilers throughout:
Marin County: Mill Valley, Tiburon, San Rafael, Larkspur, Sausalito, Corte Madera, San Anselmo, Fairfax, Novato
Sonoma County: Petaluma, Rohnert Park, Cotati, Sonoma, Glen Ellen, Penngrove
Napa County: Napa, American Canyon
NTI Boiler FAQ
Why do you recommend NTI over other brands?
Because NTI systems have proven the most reliable, quiet, and efficient in the homes we serve — especially radiant systems.
How long does an NTI boiler last?
12–20 years with proper annual maintenance.
Is the NTI TRX good for radiant floors?
Yes — it’s one of the best radiant boilers available due to low-temperature efficiency and smooth modulation.
Do NTI boilers need annual service?
Yes. All high-efficiency boilers require yearly maintenance to stay safe, efficient, and reliable.
Can NTI replace my water heater too?
Yes — the TRX Combi models provide heat + hot water in a single high-efficiency unit.
Book NTI Boiler Installation or Service
Local Plumbing is the North Bay leader in NTI installations and repairs.
- Over 50 NTI TRX installations in the last 24 months
- Licensed boiler & hydronic heating specialists
- Same-day service available
- Local team based in San Rafael, Sausalito & Petaluma
