88J53 SIT MILLIVOLT VALVE – Propane – Millivolt

Compatible Models

Astria Gas Fireplaces:
Altair40DMP
Altair40DMP-B
Altair45DMP
Altair45DMP-B
Gemini33RMP
Gemini33TMN-B
Gemini33TMP
Gemini35DMP
Gemini40DMP
Gemini45DMP
Libra40CLDMP
Libra40CRDMP
Libra40PFDMP
Libra40STDMP

Lennox Gas Fireplaces:
DR3025CPM
DR3025FPM
DR3530CPM
DR3530FPM
DR4035CPM
DR4035FPM
DR4540CPM
DR4540FPM
DRH3025CPM
DRH3530CPM
DRH4035CPM
DT3025CPM
DT3025FPM
DT3530CPM
DT3530FPM
DT4035CPM
DT4035FPM
DT4540CPM
DT4540FPM
DTH3025CPM
DTH3530CPM
DTH4035CPM
EBVCLPM
EBVCRPM
EBVPFPM
EBVSTPM
ED3530CPM
ED4035CPM
ED4035CPM-2
ED4540CPM-2
EDCLPM-2
EDCRPM-2
EDPFPM-2
EDSTPM-2
EDV3530CPM
EDV4035CNE
EDV4035CPM
EDV4540CPM
EDVCLPM
EDVCRPM
EDVPFPM
EDVSTPM
ELDV40PM
ELDV45PM
LSM40MP
LSM40MP-2
LSM45MP
LSM45MP-2
MPB-3328CPM
MPB-3530CPM
MPB35ST-PM
MPD3530CNM
MPD-3530CPM
MPD35ST-PM
MPDR3328CPM
MPDT3328CPM

Superior Gas Fireplaces:
B-40REP
B-40RMP
B-600CMN
BBV-36REP
BBV-36RMP
BBV-42REP
BBV-42RMP
BDM35
CDCL-CMP
CDCR-CMP
CDPF-CMP
CDST-CMP
D500CEP
D500CMP
D600CEP
D600CMP
D800CEP
DR-400CMP
DR-500CMP
DR-600CMP
DR-800CMP
DT-400CMP
DT-500CMP
DT-600CMP
DT-800CMP
EBCRPM-L
EBCRPM-R
EBPFPM
EBSTPM
ED4035FPM
ED4540CPM
ED4540FPM
EDCRPM-L
EDCRPM-R
EDPFPM
EDR3530CPM
EDR3530FPM
EDSTPM
EDT3530CPM
EDT3530FPM
SDDV-35PM
SDDV-40PM

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 Valve Fixes

If your fireplace uses a millivolt (standing pilot) system, the gas valve is the control center. When it begins to fail, it can cause a range of frustrating and sometimes confusing issues.

Replacing the valve often resolves the following problems:

• Pilot stays lit but burner will not turn on
  The valve is not opening when it receives voltage from the thermopile.
• Fireplace turns on intermittently or unpredictably
  Internal valve components can wear out, causing inconsistent operation.
• No response from wall switch or remote
  Even with a good thermopile, a faulty valve may not react to the signal.
• Burner shuts off unexpectedly
  The valve may be failing internally and dropping out under load.
• Weak or unstable burner flame
  Improper gas regulation inside the valve can affect flame performance.
• Gas flow issues, low flame, or no flame
  A failing valve can restrict or inconsistently supply gas to the burner.
• Clicking or switching sounds but no burner ignition
  The system is calling for heat, but the valve is not opening.
• Valve knob feels loose, stuck, or does not function properly
  Mechanical wear or internal damage to the valve body may prevent proper operation.

Important Note

Many of these symptoms can also be caused by a weak thermopile, thermocouple failure, dirty pilot assembly, switch wiring issues, or improper gas pressure. Proper diagnosis is strongly recommended before replacing the valve.

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.

How do I know if my valve is bad?

Common signs of a failing gas valve include the pilot staying lit but the burner not turning on, no response from a wall switch or remote, intermittent operation, or the burner shutting off unexpectedly.

In some cases, the valve may fail to open and allow gas to flow, even though the system is calling for heat. You may also notice inconsistent flame behavior or complete loss of burner function.

Before replacing the valve, it is important to verify that other components such as the thermopile, thermocouple, ignition module, or wiring are functioning properly, as these can cause similar symptoms.

How difficult is this part to replace?

Replacing a gas valve is considered a moderate to advanced repair because it involves working with gas lines and critical safety components.

The process typically requires shutting off the gas supply, disconnecting and reconnecting fittings, and ensuring all connections are properly sealed and leak-free. In many cases, adjustments or system checks are also needed after installation.

For safety and proper operation, installation is recommended to be performed by a qualified technician.

Is this a safe DIY repair?

Gas valve replacement involves working with gas lines and safety-critical components, so it is generally not recommended as a DIY repair for most homeowners.

Improper installation can result in gas leaks, unsafe operation, or damage to the fireplace system. Correct procedures, proper tools, and leak testing are essential to ensure safe operation.

For safety and reliability, installation is recommended to be performed by a qualified technician.

Do I need any special tools to install this?

Gas valve replacement typically requires standard hand tools such as wrenches and screwdrivers, along with gas-rated thread sealant or tape for proper sealing of fittings.

A manometer may also be needed to verify proper gas pressure after installation, and leak detection solution is required to ensure all connections are safe and secure.

Because proper setup and testing are critical for safe operation, installation is recommended to be performed by a qualified technician.