How To Change A Patio Heater Thermocouple

How To Change A Patio Heater Thermocouple
These instructions are for a BFX750 patio heater, generic patio heaters
are not covered by these instructions. For generic, unbranded or other
brands of patio heaters please refer to the original supplier or
manufacturer. Before starting you’ll need a pair of pliers, 8mm spanner
and a Philips screwdriver. Never make any repair when connected to the
LPG gas cylinder, disconnect appliance before starting and ensure the
heater has not been fired for at least 2 hours.
To change a patio heater thermocouple on branded BFX750 patio heater
remove the burner from the patio heater pole and move it onto a
workbench or table. To do this, remove the reflector by unscrewing the 3
wing nuts on top and lift the reflector and washers off. Store the reflector
and wing nuts/washers safely.
Next remove the regulator from the hose, either cut the
hose just above the regulator or unscrew the jubilee clips
to remove. Generic patio heaters may fit steel gas pipes
(not recommended) with shorter LPG hose than quality
patio heaters. Store with other parts
Loosen and remove the 4 stainless steel bolts at the top
of the patio heater pole, keep one hand firmly on the
burner when removing the bolts to hold it steady and
prevent the burner dropping to the ground. Lift the patio
heater burner off the pole, keep the hose attached to the
burner. Before making any repair check the condition of
the LPG hose, look for any splits, cracks or wear from top
to bottom.
Place the burner upside down on a workbench or table.
The surface area needs to be level to work on the
burner. Old burners may have tiny pieces of emitter
screen inside, this is normal and will not harm the
burner. A budget patio heater will have a chrome/tin
burner will be pitted with rust. Take a wire brush to
clean the burner and remove the loose rust.
All branded BFX patio heaters are true stainless steel
quality and supplied with high energy and latest energy
efficient stainless steel patio heater burner.
Remove the flame emitter screws by unscrewing the 4
stainless steel screws using the Philips type screwdriver.
They should unscrew with little pressure but should the
screws stick spray with an oil based lubricant and leave for
10 minutes to soak. If they are still stuck fast the best way
to loosen the screws is to apply a flame around the screw
to expand the burner casing. Generic chrome or tin burners
will struggle to open, most of the screws are steel type and
difficult to remove without drilling out. Store the flame
emitter screen and 4 screws with the other parts.
Remove 4 stainless steel screws just above the body of the burner.
Carefully squeeze and lift off the cylindrical mesh and thread through
hose to remove. This will give easy access to the back of the gas control
valve needed to change the thermocouple. Store with other parts.
With clear access to the thermocouple first disconnect the tilt switch. On
branded BFX patio heaters the tilt switch is AFX435 type A, on generic
patio heater or older models the tilt switch may be type C. With the pliers
pull off the two spade connectors attached to the tilt switch. Generic patio
heaters may have these soldered on, adjust accordingly.
The patio heater thermocouple is located at the
back of the gas control valve. Unscrew the
thermocouple using the 8mm spanner. Normally
the thermocouple will unscrew easily, avoid
using excessive force. When loose pull out from
the back of the gas control valve.
The thermocouple is fitted to a large sleeve nut
either silver colour as shown or on generic patio
heaters it may be brass. Loosing this will reveal
the electromagnetic valve.
Unless the electromagnetic valve require
changing it's best to leave this on.
Turn the burner on its side with the thermocouple tip facing you. Unclip
the thermocouple using the pliers. This will loosen the patio heater
thermocouple completely for removal. Take out the old thermocouple and
retain the clip. Generic patio heaters may be fitted with a steel screw to
hold the thermocouple in place. The latest patio heaters use a clip to
secure the thermocouple in place, this avoids corrosion issues with steel
Thread the new patio heater thermocouple in reverse order and
refit. Remember to leak test before lighting the patio heater, if any
leaks are found tighten any loose connection. To conduct a leakage
test see: Patio Heater Guide To Problem Solving.
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