J4118 PILOT ASSY, LP#30 – Propane – Millivolt
J4118 PILOT ASSY, LP#30 – Propane – Millivolt
⚠ Special order — Ships in 1–2 weeks
What This Part Does
The J4118 pilot assembly is a Propane LP millivolt (standing pilot) ignition component responsible for lighting the pilot flame and generating the electrical signal required to operate the gas valve.
In a millivolt (standing pilot) system, the pilot flame heats the thermocouple and thermopile. The thermocouple helps keep the pilot gas flow open for safety, while the thermopile generates the millivolt power used to operate the main gas valve.
When a call for heat is made from a wall switch, thermostat, or remote, the thermopile supplies voltage to the gas valve, allowing it to open and deliver gas to the main burner.
This assembly also includes the pilot burner and ignition source, which are responsible for reliably lighting the pilot flame.
Proper pilot assembly operation is essential for safe ignition, consistent voltage generation, and reliable fireplace performance.
Not sure if this is the right part?
Before ordering, check the following:
- Locate your model number (typically behind the lower louver or inside the control compartment)
- Confirm your unit uses a millivolt (standing pilot) system
- Confirm your gas type is propane (LP)
- Compare your existing pilot assembly to the images provided
⚠️ This part is NOT for IPI (electronic ignition) systems
⚠️ This part is NOT for natural gas (NG) units
If unsure, refer to your manual or contact us for help identifying the correct part.
🔁 Using natural gas (NG) instead of propane (LP)?
This part will not work. View the correct NG version here: J4117
Compatible Models
Astria Gas Log Sets:
MagniFlameOD24PM
MagniFlameOD30PM
Desa Tech Gas Fireplaces:
(V)CD36TP
(V)DVF36TCLP(E)
(V)DVF36TCRP E
(V)DVF36TPNPA-A
(V)DVF36TPNPEA-A
(V)DVF36TSTPA-A
(V)K36P
(V)K36PH
(V)T32P-A
(V)T32PB-A
(V)T32PRB-A
BDV34P
BDV34PA
BDV34PB
BDV37P
BDV37PC
BDV41P
BDV41PC
BHDV34PA
BHDV34PB
BHDV37PC
BHDV41PC
CD36RP
CD36TP
CDV34PA
CDV37P
CDV41P
CGCDV36PR
CGCDV42PR
CGDV32PR
CHDV37P
CHDV41P
DDV37P
DDV41P
DVF34P
DVF36TCLP
DVF36TCRP
DVF36TPNPA-A
DVF36TSTPA-A
DVF42KP
DVFH34P
DVM36KP
DVM36TP
DVM36VP
DVM42VP
KC36P
KC36PH
KC42P
KC42PH
MBDV37P
MBDV41P
O36PRA
O36PRB
O36PRHA
O36PRHB
O36PRRA
O36PRRB
O36PRRHA
O36PRRHB
O42PRA
O42PRB
O42PRHA
O42PRHB
O42PRRA
O42PRRB
O42PRRHA
O42PRRHB
T32P-A
T32PB-A
T32PR-A
T32PRB-A
TC36P
TC36PB
TVTC36P
V)CD36RP
V32PR-A
V42P-A
V42PSB(1)
VC36P
VC36PB
VC36PH
VC42P
VC42PB
VC42PH
VCD36RP
VCD36TP
VDVF36TCLP
VDVF36TCRP
VDVF36TPNPA-A
VDVF36TSTPA-A
VHC36P
VKC36P1
VKC36PH1
VKC42P
VKC42P1
VKC42PH1
VO36PRA
VO36PRB
VO36PRHA
VO36PRHB
VO36PRRA
VO36PRRB
VO36PRRHA
VO36PRRHB
VO42PRA
VO42PRB
VO42PRHA
VO42PRHB
VO42PRRA
VO42PRRB
VO42PRRHA
VO42PRRHB
VT32P-A
VT32PB-A
VT32PRB-A
VTC36P1
VTC36PB1
VV36PHC1
VV36PSC1
VV3PC1
VVC36P
VVC36P1
VVC36PB1
VVC36PH1
VVC42P
VVC42P1
VVC42PB1
VVC42PH1
FMI Gas Fireplaces:
CD36M-A
Vantage Hearth Gas Fireplaces:
CHDV32NR
System Type
This is a millivolt standing pilot system. These systems use a continuously burning pilot flame and do not require household electrical power for basic operation.
Millivolt systems are commonly found in many direct vent gas fireplaces and are known for simple, reliable operation.
This system commonly includes:
- Thermocouple — helps keep the pilot gas valve open when the pilot flame is proven.
- Thermopile — generates millivolt power used to operate the main gas valve.
- Igniter electrode — provides manual spark ignition, usually from a push-button piezo igniter.
- Pilot tube — delivers gas from the valve to the pilot assembly.
Because these systems do not rely on external power, they can often operate during a power outage when used with a manual switch or compatible battery-free control setup.
These systems offer improved efficiency, remote-control compatibility, and added safety features, but they also include more electronic components than a millivolt system.
Common Problems This Part Fixes
If your fireplace uses a millivolt (standing pilot) system, the pilot assembly is responsible for generating the voltage needed to operate the gas valve and proving flame safety. When it begins to fail, it can cause a range of ignition and operating issues.
Replacing the pilot assembly often resolves the following problems:
- Pilot will not stay lit
A weak or failing thermocouple may not keep the gas valve open. - Pilot lights but goes out when the knob is released
The thermocouple is not properly generating or delivering a safety signal. - Pilot flame is weak, small, or unstable
A clogged pilot orifice or worn components can affect flame quality. - Burner will not turn on even though pilot is lit
A weak thermopile may not generate enough voltage to operate the valve. - Intermittent operation or delayed burner ignition
Inconsistent voltage output from the pilot assembly can cause unreliable performance. - No response from wall switch or remote
Insufficient millivolt output can prevent the system from activating. - Difficulty lighting the pilot
A worn igniter electrode or misaligned pilot components can prevent proper ignition.
Important Note
Many of these symptoms can also be caused by a faulty gas valve, loose wiring, or improper gas pressure. Proper diagnosis is recommended before replacing the pilot assembly.
Warranty Information
This product includes a 12-month warranty from the date of purchase. This warranty covers defects in materials or workmanship under normal operating conditions.
Fireplace components must be properly installed and matched to the correct system (millivolt vs IPI, natural gas vs propane).
This warranty does NOT cover:
• Improper installation or incorrect application
• Use with the wrong gas type (NG vs LP)
• Misdiagnosis of the issue
• Damage caused by other failing components
• Normal wear and tear
• Labor, service, or diagnostic time
Because many fireplace issues can be caused by multiple components, we strongly recommend confirming the diagnosis before replacing parts.
We are happy to assist with this. Proof of purchase is required for all warranty claims. Please contact us prior to removal or replacement of the part so we can help verify the issue and guide the warranty process.
Do I need any special tools to install this?
Most pilot assemblies can be installed using basic hand tools, and no specialized equipment is typically required.
In most cases, you will need:
• Adjustable wrench or open-end wrenches
• Screwdrivers (Phillips and/or flathead)
• Nut driver or socket set
The pilot assembly is usually mounted near the burner and connected by a pilot tube and thermocouple or thermopile. Installation involves removing the old assembly, reconnecting the gas line components, and securing the new pilot in place.
It is important to ensure all connections are tight and properly aligned. After installation, always check for gas leaks using a leak detection solution and confirm proper pilot flame appearance.
If you are unsure or uncomfortable working with gas components, we recommend having a qualified technician perform the installation to ensure safe and proper operation.
Do I need to make any adjustments after installation?
In most cases, no major adjustments are required after installing a pilot assembly, but a few important checks should always be performed to ensure proper operation.
After installation, you should:
• Verify the pilot flame is steady and properly positioned over the thermocouple or flame sensor
• Confirm the flame is strong enough to fully engulf the sensor (not weak or lifting)
• Check all gas connections for leaks using a leak detection solution
Some systems may include a pilot adjustment screw on the gas valve. If needed, this can be used to fine-tune the pilot flame height, but many modern systems are preset and do not require adjustment.
If the pilot flame appears weak, unstable, or does not stay lit, this may indicate an issue with gas pressure, air in the line, or another component in the system.
Proper flame appearance and stable operation are key to safe and reliable performance. If you are unsure about flame characteristics or adjustments, we recommend consulting a qualified technician.
How difficult is this part to replace?
Replacing a pilot assembly is generally considered a moderate repair and can often be completed by a homeowner with basic mechanical skills.
The process typically involves accessing the burner area, disconnecting the pilot tube and sensor leads, removing the old assembly, and installing the new one in the same position.
While no specialized tools are usually required, the work does involve gas connections and components that must be installed correctly to ensure safe operation.
For someone comfortable working with hand tools and following instructions carefully, this is a manageable repair. However, access to the pilot assembly can vary depending on the fireplace model, and some units may require additional disassembly.
If you are unsure about working with gas systems or identifying proper flame characteristics after installation, we recommend having a qualified technician perform the replacement.
How do I know if my pilot assembly is bad?
A bad pilot assembly will usually show clear symptoms related to ignition problems or unstable flame performance.
Common signs of a faulty pilot assembly include:
• Pilot will not light at all
• Pilot lights but will not stay lit
• Weak, small, or flickering pilot flame
• Pilot lights but the main burner does not turn on
• Intermittent operation or frequent shutdowns
In many cases, the issue is caused by a worn or failing thermocouple or thermopile, a clogged pilot hood, or a damaged ignition component. Dirt, dust, or corrosion can also affect how the pilot flame contacts the sensor.
A proper pilot flame should be steady, strong, and fully engulf the thermocouple or flame sensor. If the flame is weak, not making good contact, or going out unexpectedly, the pilot assembly may need to be cleaned or replaced.
Before replacing the assembly, it is also important to rule out other possible causes such as low gas pressure, air in the gas line, or a faulty gas valve.
If cleaning does not resolve the issue or the components show signs of wear or damage, replacing the pilot assembly is often the most reliable solution.