Replacing A Patio Heater Thermocouple

Patio heaters are fitted with a thermocouple, this device controls the flow of gas and ensures it’s working normally. A thermocouple that has failed will switch the burner off, you’ll notice this when the pilot lights but goes off when turned up. Changing the thermocouple fixed 90% of the firing problems, if you ever wondered how to change one just read on.

You’ll need a 8mm spanner, pliers and Philips type screwdriver.
Make sure the lpg gas cylinder is NOT connected, and heater has NOT been fired up for at least 60 minutes.

These instructions are for branded BFX750 gas patio heaters, generic or unbranded patio heaters can vary. Some additional tips are included for generic patio heaters.

The patio heater thermocouple cannot be safely accessed in situ, you’ll need to take the burner off the pole. To do this remove the wing nuts holding the reflector and lift the reflector off. Next disconnect the gas regulator, either unclip or cut the LPG hose close to the fitting. Older generic patio heaters may have a steel gas pipe that runs inside the pole, if so you’ll need to replace the small washer seal inside when refitting. Remember to store all the parts for reassembling later.
Most patio heaters will have 4 stainless steel bolts securing the burner to the pole, see picture below. Unscrew and take care holding onto the burner to ensure it doesn’t fall off.

patio heater pole fixing screws

Patio Heater Pole Fixing Screws

With the burner off the pole place it upside down in on a table or a work area. First check for any cracks or wear to the LPG hose, replace the hose if there are any signs of damage. You will notice some small bits of metal inside the flame screen, this is normal and will not harm the burner. Branded BFX750 patio heaters have a stainless steel casing, generic patio heaters are often manufactured in tin or chrome so the casing on a generic heater could be pitted. If you have a lot of rust use a wire brush to clean and remove as much as you can. If the rust is very bad (tin/chrome burner have a life of 2 years or less near coastal areas) then it might not be worth salvaging.

patio heater burner repair

Patio Heater Burner Repair

With the Philips type screwdriver unscrew the 4 stainless steel screws holding the flame emitter screen in place. Normally they will unscrew with ease but tin/chrome burners may struggle, if so try using a blow torch to loosen the screws. Store with other parts.

patio heater flame emitter screen

Patio Heater Flame Emitter Screen

The easiest way to access the thermocouple is to take the mesh off in one go, unscrew the stainless steel screw at the top of the mesh panel – see picture below. Lift the mesh off by squeezing; it should come away in one cylinder. You now have full access to the patio heater gas control valve and tilt swtich if fitted. Store with other parts for reassembling later.

burner mesh screws

Remove Mesh Screws

Good quality patio heaters will have a tilt switch fitted as standard, this is a small black box with 2 leads. The tilt switch turns the gas off when the patio heater is tilted or moved. Take the pliers and pull off the 2 spade connectors attached to the tilt switch. On some generic patio heaters these can be soldered on in which case you’ll need a soldering iron to remove.

remove patio heater tilt switch leads

Remove Tilt Switch Leads

You’ll see the thermocouple at the back of the patio heater gas control valve. Using the 8mm spanner unbolt the small brass connector to loosen and remove the thermocouple. This should unscrew easily, just pull away from the back of the gas valve – see below.

pull thermocouple away from gas valve

Rear Of Gas Valve

Last job is to flip the burner upright facing towards you. You will see the tip of the thermocouple, on branded BFX750 patio heaters the thermocouple is held in place using a clip. Since a thermocouple is a consumable item that will require changing every few years this system is designed for ease of use. Generic patio heaters may use a steel nut, these tend to corrode and make it difficult to remove. Just unclip using the pliers and the thermocouple is now ready to remove – see below.

unclip patio heater thermocouple

Unclip The Patio Heater Thermocouple

Pull the old thermocouple out and you are ready to refit a new patio heater thermocouple. Follow the instructions in reverse order and when done ensure a leakage test is conducted before firing up the patio heater. For instructions on how to leak test and solutions to other patio heater problems please read Patio Heater Guide To Problem Solving.

replace patio heater thermocouple

Replacing A Patio Heater Thermocouple

Want to know the difference between a domestic patio heater and a commercial heater?

It’s a grey area trying to work out what a commercial patio heater is compared to a standard domestic patio heater and also if you need commercial quality or will domestic do just as well?  The problem is that from distance they are both the same height, work the same and look the same. So here are the things to look for on commercial patio heaters.

Steel used in manufacture of patio heaters

The majority of domestic stainless steel patio heaters will have a very shiny finish, the stainless steel grade will be 202 grade or lower which is just above corrosion resistance.  This is used on the housing (bit around the cylinder) and pole.  Bases can be the same but most often they are either plastic or steel with a paint finish.  The burner on domestic is just tin plated or chrome.

Commercial heaters use either 304 or 316 marine grade stainless steel which in the majority of heaters is a brushed finish giving more professional look that will not show up marks and dings.  This higher grade of stainless steel is used on all parts including the burner to ensure a perfect match.  For areas close to the sea, corrosion from sea spray or saline fog is a major problem, higher grade stainless steel will last much longer.  Inland areas may be less problematic to salt, however a tin/chrome burner fitted on domestic heaters will still corrode but instead of a few months it might get up to 15 months life expectancy.

Patio heater components

Inside the burner are the working, a thermocouple, tilt switch, gas valve, leads and mantle.  Domestic patio heaters use an all in one thermocouple/tilt assembly to save production time and costs.  These are much thinner with a typical life of 1 to 2 years before replacing. The gas valves are a lower grade with a simple bracket fitting.

On a commercial burner the thermocouple is a single heavy duty connection, this is a more complicated way but longer lasting giving as much as 4 times the quality and life. You have to remember that within a commercial environment these heavy duty burners run for 8 hours at a time and 7 days a week.  Commercial premises don’t want to keep changing the thermocouple every few weeks so they have to be up to the job.  If you put a domestic thermocouple in a commercial heater it would last 3 to 6 months max.

commercial patio heater versus domestic

Commercial Versus Domestic Patio Heaters

Both patio heaters look very similar

From the picture above you’ll not see much difference apart that the domestic patio heater has a drinks table. Insurance and fire regulations in many commercial premises will not permit drinks table just in case someone whose has drunk a little too much nectar decides to lean heavily on the drinks table, the outcome may not end well!  Take a look at the wheels this gives a hint of a clue which is the more robust. From afar they just look the same but up close it does become clear but only side by side.  If you saw one on its own it is difficult to tell.

Which patio heater is best?

It’s all down to how you want to use your patio heater.  For normal garden use a domestic patio heater is brilliant, it will do everything you want and work just the same as the ones in pubs. You really don’t need the extra heavy duty unless you really want the very best, and many do!  But, for a pub life a domestic patio heater will need more maintenance and cannot be moved on a daily basis without some serious wear and tear resulting in a tatty looking heater.

So if you know how and where you are going to use your patio heater it’s just a matter of deciding on the budget or is it.  There are rogue traders offering patio heaters with 75% off, so you might think it’s a commercial heater with a big discount – wrong.  These are just dodgy traders offering domestic heaters with an inflated or made up RSP and claiming to offer 75% off the ticket.  The reality is these heaters are worth far less than they sell them for, so it’s a double con. Rogue traders use pop up web sites and change trading names when the law catches up with them, so do your research and ask the questions, that way you can work out what you are buying and if it’s the right patio heater and right for you. And one last thing, all patio heaters need spare parts, if the seller doesn’t supply spares, offer support and back-up then you know where you stand, when the patio heater goes wrong it will be down to the tip!  Save time and don’t waste your money on tin heaters, direct factory supply will give good advice, support and cost less to buy and run than many of those here today gone tomorrow deal.