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

25 thoughts on “Replacing A Patio Heater Thermocouple

    • Hi Nick
      All gas patio heaters will have a thermocouple fitted but not all have the same one and some are wired up a different way. Best advice is to get the patio heater thermocouple in your hand and compare online, check the measurements for a good fit. Some patio heaters fit thermocouples with fixing nuts, these types can be adapted to a clip type.
      Good hunting

  1. I think my patio heater needs a new thermocouple fitted, it’s getting harder to get it working and sometimes just goes out. There is no marking on it, bought it less than a year ago online and I can’t get a reply when I phone them. How do I know which thermocouple will fit my patio heater.
    Can you help please
    Gill

    • Hi Gill
      If you patio heater goes out when you turn the pilot to full it’s would point to a worn thermocouple. There are different types but if you can see rust spots on the burner then it will be the budget type which has chrome or polished tin burners. These have a Chinese thermocouple AFX480, if you replace it this should fix the firing issue. There are patio heaters with stainless steel burners but the only one we know is the BFX750 stainless steel patio heater.
      Hope this helps

  2. I discovered your “Replacing A Patio Heater Thermocouple” page and had the same problem with my new 16kw patio heater bought on an auction site last year. It never worked from day one, the seller ignored my messages and closed the seller a/c. Nearly took the heap of junk down the tip but took the thermocouple out and now it works 🙂 Might get a year or two from it, it’s starting to wobble a bit and the top has rusted but I guess that is normal.

  3. Somebody tell me why my patio heater needs a repairing when it’s not even a year old? The gubbings all melted inside and the seller said it’s my fault. Told me to read the instructions and go away – yeh, get lost! Paid good money.

    • Hi Dan
      This is not bad luck but bad design of a gas patio heater!
      We have seen this time and time again with patio heaters that have a steel gas pipe that runs down the pole. The problem with this design is you cannot connect a leakage test as a fitting is inside the pole, crazy and dangerous. There are many issues to this design but the main one is that each time your disconnect the regulator from the cylinder the hose is moved from side to side. This loosen the nut at the top of the pole which is hidden and gas slowly escapes. After a while the build up of gas catches fire as gas is heavier than air and flames jump downwards. Hence all the controls catch alight and melt.

      Do not attempt a repair, this is a write off. The only solution is a new burner, the safest one on the market is BFX150 stainless steel patio heater burner. No steel pipe with belt and braces construction.

      Please don’t give up, not all patio heaters have this poor design take a good look around for ones that are well built. Just a quick tip, budget patio heaters are just that – made cheaply!
      Best of luck

    • Hi Keith
      US gas patio heaters will have a thermocouple fitted, which one will depend on the manufacturer and year it was made. Best advise is get your old thermocouple in your hand and compare online, the main measurement is size of thread that screws into the gas valve.

    • Hi Irene
      Table top patio heaters have a longer thermocouple fitted than the standard free standing types. Unfortunately these are not a common part and hard to find, I’d suggest going back to the supplier but I know many patio heater stockist don’t keep spare parts for when things need changing.
      Good Hunting

    • Hello Robbo
      Interesting, our engineer reckons it might work on some thermocouples if they are not too far gone but it will only give a few hours more running time!
      Worth it if you need to run your patio heater for a few hours but eventually the thermocouple will still need to be changed.

  4. Cheers mate, worked a treat on my Enders patio heater. Tried to call them but their phone line is dead?
    Big Al

    • Hi Al
      Enders went last year, their phone is probably now disconnected.
      Not sure if Enders will still be about or if they will supply patio heater spare parts, most of it comes out of China which is a long way to ship!
      Try Patio Heaters 4U, all parts sent from UK.

  5. Hi! Found your weblog when searching on Google.
    I have a load of gas patio heaters in my beer garden that keep going out. Changed all the thermocouples and it fixed the problem, very helpful info.
    many thks
    Baz

  6. You have a wonderful blog!
    I would like to invite you to post some blogs on my weblog?
    Let me know if you are interested.
    Seb

    • Hi Seb
      Sorry to disappoint you but we’re not professional web bloggers, patio heaters is our industry and we’re just trying to give useful information and tips.
      Hope you find some help out there is blogworld.

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