SRV51704 SENSOR TEMP FAN SWITCH – N/A – N/A
SRV51704 SENSOR TEMP FAN SWITCH – N/A – N/A
⚠ Special order — Ships in 1–2 weeks
What This Part Does
This thermodisc is a temperature-activated switch used to automatically control fireplace blower fan operation.
The switch monitors fireplace temperature and changes state at a preset temperature point. In most fireplace applications, the thermodisc remains open while the fireplace is cool and closes once sufficient heat is reached, allowing power to flow to the blower fan.
As the fireplace cools down after operation, the thermodisc opens again and automatically shuts the blower off.
Thermodiscs help improve comfort and efficiency by preventing the blower from running until usable heat is available and stopping fan operation once the appliance cools.
Different thermodiscs may use different temperature ratings and switch configurations depending on the fireplace design.
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 N/A system
- Compare your existing thermodisc to the images provided
⚠️ This part is NOT for a different ignition/control system systems
Compatible Models
Majestic Gas Fireplaces:
33BDVR
33BDVT
33RDVDSN
33RDVN
33TDVDSN
33TDVN
33XDVR
36BDVR
36BDVT
36LDVT
36RDVDSN
36RDVN
36TDVDSN
36TDVN
39BDVT
39LDVT
39RDVDSN
39RDVN
39TDVDSN
39TDVN
41DVDSN
41DVN
43BDVR
43BDVT
43LDVT
DV40RN
DV40RP
DVRS3
DVRSL
DVRSR
DVRT36
DVRT39
DVRT41
DVRT43
DVRTSB
DVT36
DVT39
DVT43
DVTS2
FSDV22
FSDV30
FSDV32
FSDV42
HEDV32
LHEC20
LHEC30
RFSDV24
Majestic Gas Inserts:
FS22
HE20
HE25
HE30
HE32
HEB30
HEB32
HEB42
HEDV30
LHECDV20
LHECDV30
RFS22
RFS32
RFS42
RHE25
RHE32
RHE42
RHEB42
Majestic Gas Stoves:
33LDVR
33LDVT
360DVS2
360DVS2RNMH
360DVS3
360DVSL
360DVSR
43LDVR
DV360
DV580
DVB4136
DVR33
DVR36
DVR39
NV360
NVC36
NVC39
NVC43
RDV4136
RFSDV22
RFSDV24SR
RFSDV32
RFSDV32RMH
RFSDV42
RHEDV25
RHEDV32
RHEDV42
Vermont Castings Gas Stoves:
33XDV
36LDVR
36XDV
39BDVR
39LDVR
39XDV
FSUV20
RFSUV34
UVC36
UVC43
UVS33
UVS36
UVS43
Common Problems This Thermodisc May Fix
- Blower fan never turns on
- Fan runs constantly even when fireplace is cool
- Fan operation is intermittent
- Blower starts too late or shuts off too early
- No automatic fan operation
- Fireplace overheats due to blower not activating
- Fan only works when bypassed manually
- Temperature-activated blower control failure
A thermodisc is a temperature-sensitive switch commonly used to automatically control blower fan operation in a fireplace.
Most fireplace thermodiscs are normally open switches that close at a preset temperature to activate the blower once the fireplace warms up. The switch then opens again as the fireplace cools down, shutting the blower off automatically.
Before replacing the thermodisc, also inspect the blower motor, wiring, fan speed control, and power supply, as these components can cause similar symptoms.
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 difficult is this part to replace?
Thermodisc replacement difficulty varies depending on the fireplace design and the location of the component.
In some fireplaces, the thermodisc is easily accessible near the blower assembly and can be replaced quickly with minimal disassembly. In other units, access may require removal of panels, controls, or blower components.
Most replacements involve basic wiring connections, but proper access and reassembly are important for safe and reliable operation.
Do I need any special tools to install this?
Most thermodisc replacements only require basic hand tools such as screwdrivers or nut drivers to access and replace the component.
Depending on the fireplace design, additional disassembly may be required to reach the thermodisc location, especially in tighter blower compartments or rear-mounted installations.
Always disconnect power before servicing electrical components and verify all wiring connections before operation.
Is this a safe DIY repair?
Many thermodisc replacements are considered manageable DIY repairs because they typically involve simple wiring connections and mounting hardware.
However, accessibility can vary significantly depending on the fireplace design. Some thermodiscs are easily accessible near the blower compartment, while others may require substantial disassembly to reach safely.
Always disconnect power to the fireplace before servicing electrical components.
How do I know if this part is bad?
Common signs of a failing thermodisc include the blower fan not turning on, the fan running continuously, delayed fan operation, or inconsistent blower performance.
A defective thermodisc may fail to open or close at the correct temperature, preventing the fan circuit from operating properly.
Before replacing the thermodisc, verify that the blower, wiring, speed control, and power supply are functioning correctly, as these components can cause similar symptoms.