NJ Form F370, the chimney verification for replacement of fuel-fired equipment, is a one-page certification your HVAC contractor signs to confirm that an existing chimney or flue can safely vent a newly installed furnace, boiler, or water heater. It takes the place of the more invasive inspection step that would otherwise require removing and reinstalling the vent connector so a code official could look directly into the flue.1New Jersey Administrative Code. New Jersey Code 5:23-2.20 – Tests and Special Inspections The form must be signed by the installing contractor. Homeowners cannot sign it in place of the required inspection.
When You Need Form F370
You need the form whenever fuel-fired heating equipment is replaced and the new appliance will vent through an existing chimney or flue. Replacing a furnace, boiler, or water heater in a one- or two-family home is the typical trigger. Under the New Jersey Rehabilitation Subcode, this work is classified as a renovation, and the applicable portions of the International Residential Code require the chimney passageway to be inspected before the replacement appliance is connected.2New Jersey Department of Community Affairs. Construction Code Communicator – Fall 2016
The reason is practical. A new appliance rarely produces the same exhaust volume and temperature as the old one. High-efficiency condensing furnaces generate lower-temperature flue gases that can cause moisture to condense inside a masonry chimney, degrading the liner and creating a carbon monoxide risk. Form F370 forces someone with hands-on knowledge of the installation to verify the chimney is sized correctly, properly lined, and structurally sound for what the new equipment puts out.
There is one narrow exception. If the replacement appliance is the same type, has the same input rating, and operates at the same efficiency as the unit being removed, and the existing chimney already meets sizing and condition standards, continued use of the chimney may be allowed without the full verification process.3ICC Digital Codes. New Jersey Residential Code 2021 – Chapter 18 Chimneys and Vents Most replacements involve at least a change in efficiency, so the form applies to the great majority of jobs.
Who Can Sign the Form
Only the contractor who installed the replacement equipment can sign Form F370. The regulation is explicit that “Verification from homeowners shall not be accepted in lieu of the required inspection.”1New Jersey Administrative Code. New Jersey Code 5:23-2.20 – Tests and Special Inspections If you are a homeowner doing permitted work yourself, the construction official will require the standard chimney inspection, meaning the vent connector gets removed so the inspector can examine the flue directly.
The contractor who signs takes legal responsibility for the accuracy of what is reported. A false or misleading statement on the form can trigger penalties under the Uniform Construction Code, which is why reputable installers treat the F370 as a genuine assessment rather than a formality.
What Information Goes on the Form
The form is one page, but it asks for specific technical data that requires the contractor to physically examine the chimney and know the specifications of the new appliance. The information falls into three categories.
Chimney and Flue Details
The contractor identifies whether the chimney is masonry or factory-built metal, and records the liner type: stainless steel, aluminum, or clay tile. Chimney height and interior flue diameter are measured, since both affect whether exhaust gases draft properly. The contractor also inspects the interior of the flue to confirm the liner is continuous from the appliance connection to the termination point above the roofline, with no blockages, cracks, or gaps that could let combustion products escape into the home.3ICC Digital Codes. New Jersey Residential Code 2021 – Chapter 18 Chimneys and Vents
If the chimney previously vented a solid-fuel or oil-burning appliance, it must be cleaned before a gas appliance is connected, regardless of its apparent condition.
Appliance Specifications
The form requires the total BTU input rating of every appliance venting into the same flue. This is the single most important number on the form, because chimney sizing depends on it. The contractor also records the diameter of the vent connector pipes running from each appliance to the chimney. Together these measurements let the code official verify that the flue diameter is adequate for the combined load and that venting velocity will prevent backdrafting.
Liner Material Compatibility
Different fuels and appliance efficiencies produce exhaust at different temperatures, so the liner material has to match. Aluminum liners have a lower melting point and should only be used with lower-efficiency gas appliances, generally those rated below about 83 percent efficiency. Stainless steel handles higher temperatures and is required for oil-burning or high-efficiency gas equipment. Aluminum must never be used for wood-burning appliances. If the existing liner does not match the new appliance’s requirements, the chimney will need relining before the installation can pass inspection.
How and When to Submit the Form
Where the completed form goes is always the same place: your local municipal construction code enforcement office. When it goes there depends on how the work is classified.
- For minor or emergency work, Form F370 must be submitted with the permit application. The permit cannot be filed without it.1New Jersey Administrative Code. New Jersey Code 5:23-2.20 – Tests and Special Inspections
- For all other work, the form must be presented to the code official before the final inspection.4New Jersey Department of Community Affairs. Chimney Verification for Replacement of Fuel-Fired Equipment – Form F370
The Department of Community Affairs advises submitting one original plus three photocopies of each form in your permit packet.5New Jersey Department of Community Affairs. Construction Permit Application Packet and Related Forms Some municipalities accept electronic submissions through online permit portals, but many still require paper forms delivered in person.
What the Inspector Does With It
The construction official reviews the data on the F370 to confirm the venting configuration complies with the applicable subcode. After the equipment is installed, a state-licensed inspector visits the site to verify that what is reported on the form matches reality. The final certificate of approval for the mechanical work will not be issued until that inspection is complete.
If the inspector finds the chimney does not match the form, whether that is the wrong liner material, an undersized flue, blockages, or structural defects not disclosed, the inspector can issue a notice of violation or require immediate remediation. The contractor who signed the form bears responsibility for the discrepancy. In the worst case, the installation gets red-tagged and the equipment cannot be operated until the venting system is brought into compliance.
When Relining Comes Up
The verification process frequently reveals that relining is necessary, particularly when a newer high-efficiency appliance replaces older equipment. Exterior masonry chimneys are especially likely to need relining for furnace or boiler installations, because the cooler exterior temperatures compound the condensation problem.2New Jersey Department of Community Affairs. Construction Code Communicator – Fall 2016 The code requires the chimney to be resized as necessary to control flue gas condensation and provide adequate draft.3ICC Digital Codes. New Jersey Residential Code 2021 – Chapter 18 Chimneys and Vents If the contractor’s assessment indicates the existing flue is oversized or unlined, the code official will require relining or other corrective work before approving the installation.
Penalties for Skipping It or Filing False Information
Skipping the chimney verification or filing inaccurate information carries real consequences. The Uniform Construction Code Act penalty structure applies to both property owners and contractors.
- Working without a required permit: up to $2,000 per violation.6New Jersey Department of Community Affairs. New Jersey Statutes Annotated 52:27D-138
- False or misleading statements on the form: up to $2,000 per violation, with each false statement counted as a separate offense.7New Jersey Administrative Code. New Jersey Code 5:23-2.31 – Compliance
- Failing to comply with a stop-construction order: up to $2,000 per violation, with each day of noncompliance treated as a separate offense.
- Refusing inspector access: up to $250.7New Jersey Administrative Code. New Jersey Code 5:23-2.31 – Compliance
- Other code violations: up to $500 per violation, rising to $2,000 if the violation endangers life or safety, which a defective venting system certainly could.7New Jersey Administrative Code. New Jersey Code 5:23-2.31 – Compliance
Beyond the fines, a code violation tied to a venting system can prevent issuance of the certificate of approval for the entire mechanical project. The new furnace or boiler then sits idle, installed but legally unusable, until the problem is corrected and reinspected.
Where to Download the Form
Form F370 is available as a free PDF download from the New Jersey Department of Community Affairs Construction Permit Application Packet page under “Related Forms.”5New Jersey Department of Community Affairs. Construction Permit Application Packet and Related Forms Your local building department may also have printed copies. The current revision is dated 01/12, and no updated version has been issued since.
One naming note. Older references sometimes call this form “UC-09.” That designation actually belongs to an unrelated New Jersey Department of Labor form for employer refund claims. The correct designation for the chimney verification form is U.C.C. F370. If your contractor or municipal office refers to a “chimney cert” or “F370,” they mean this form.