Potterton Promax Leakage in Central Heating System


I am here to share my problem regarding Potterton ProMax boiler. Two days ago, I heard some weird noises like whooshes & hisses directly coming out of the central heating system and today my boiler’s heating system is losing pressure whenever I turn it on. I am worried will someone please help me?



Hi Nail, apparently it is due to the leakage in boiler’s central heating system. I would suggest calling a specialist to resolve this issue immediately before the leaking water will cause severe damage to the boiler’s heating system & walls and floor around it. Meanwhile, you can also find the leaks by following these steps:

  • Fill your boiler with water to examine that how much it takes for water to drain
  • Place colored paper or sheet under your boiler. In case you see any drops on the paper or sheet, it will be very easy for you to find the leakages in the central heating system.
  • Do check different parts of your boiler


Potterton Combi E133

My Potterton Combi boiler fails to ignite permanently. It shows E133 error. Has someone any information about it? Will restarting the boiler help in this regard or should I ask for assistance from service center immediately?


Hi Tom,

E133 means no ignition; failures of different parts can cause this issue such as the soothed burner, PCB, ignition and flame detection electrode, high voltage cable, gas valve and blocked condensate. In your case, restarting the boiler can help at least temporarily. However, if problem lasts call service in order to replace the problem causing parts if you do not have required qualifications.

Potterton Combi Losing Pressure


I have a combi boiler that keeps losing pressure and the overflow is leaking, every 2 hours or I have to keep topping it up so that I have some warmth, any suggestions?



Hi Bob, Your Potterton combi boiler is losing pressure due to different reasons. Loss of pressure might be caused because of the leakage in a pressure relief valve, a problem in an expansion vessel, leakage in the heating pipework and air in the boiler. Leaking boilers, leaking radiators and leaking pipework can lead to constant loss of pressure in your boiler. Most of the Potterton combi boilers have built-in pressure meters you can use to check easily if there is the loss of pressure, as boiler needs continuous water pressure in order to run properly.

Potterton Combi Boiler Turns off Automatically


My Potterton combi boiler was working fine until now but developed a serious problem as it keeps turning itself off automatically. Is someone there to help me on this matter?



Hi James

There could be three main reasons behind this issue, firstly, perhaps your Potterton boiler is leaking. If not, then you might have the damaged pressure relief valve & will need to replace it by an engineer. Another reason relates to the thermostat, if it has been broken then your Potterton boiler cannot identify the temperature of water & it will turn itself off to prevent the machine from overheating. You have to change the thermostat. You can save your money by buying a new thermostat as it can reduce the energy bills in future. Finally, do check the water flow. If the Potterton boiler keeps turning itself off, it can be because of closed valve, broken pumps & air gathered in the system.

Potterton Combi Overheating

Hi Everyone,

I am looking for some reliable information on an issue with my 4-years-old Potterton combi boiler. I am suspecting that my boiler is overheating repeatedly even after replacing the air expansion tank & pressure relief valve. What could be the possible reason behind it?



Hi William, if you doubt that your Potterton combi boiler is overheating then, you should turn off water supply immediately. Do not try to cool or repair it yourself. I would recommend you to turn off the water and gas supply. Overheating also relates to plugging up & removal of the pressure release valves in order to resolve leakage issues, wiring errors & manual opening of the gas valves. If the problem persists, contact a qualified Potterton combi boiler engineer immediately.

Potterton Combi Failed Thermostatic Blender Valve


I am a very satisfied customer of Potterton Combi boilers. However, from past 1 week, my boiler is not working as expected and hot water cools down suddenly. What could be the possible reason?


Hi Ian,

Thermostatic blender valve failure sometimes leads to such scenario. It can easily fix with the installation of a new valve. However, before applying this fix, water scale must also be checked for issues. Please check if your boiler has an external plate and heat exchanger, if so then you can replace it easily and hot water flow can be ensured. Most of Potterton combi boilers have internal water exchangers installed, however the chemical process is required. The process itself is not tough however a lengthy process. Therefore, I would recommend you to take an expert help in order to avoid further problems.


Potterton Promax Combi Banging & Clanking Noises

Hi All,

I have a 10 years old Potterton Promax combo, which was working absolutely fine until last week. It suddenly started creating clanking and banging sounds. These sounds start loud however, they decreases after some time. Should this be something I need to worry about or not?


Hi Robert, These noises can be due to kittling reasons. This usually occurs in heat exchanger when limescale results in oxygen bubbles formation on its surface. The phenomenon is same as the sound you get from heated immersion heater or kettles. Other reasons for sounds can be gas vs. water flow rate. For older wall-mounted boilers, it is turning out to be a common problem. If the heat exchanger is damaged then get it replaced immediately. Else, follow these simple instructions to bring it back to usual working for a couple of more years for sure.

  1. Get a though clean up and service of your boiler
  2. Check the gas pressure in accordance with water flow and refer to a manual for details.

Potterton Surprima Condensate Pipe


I bought Potterton Surprima boiler 5 years ago. It was showing a great performance until yesterday. Unfortunately, yesterday I realized that boiler’s condensate pipe is blocked or frozen. Can I fix it at home?



Hi Jonny,

Condensation is a normal issue in the boiler & is caused when gas in the boiler is burned in order to generate heat. Usually, this condensation will discharge automatically directly into drain outside or inside the house. Unprotected or incorrectly installed condensate pipes of the boiler can freeze easily in extreme weather conditions thus, preventing your boiler to work properly. You can fix it easily, just go outside the home, and find the condensate. It is advisable to try using the hot water kettle to liquefy it out. After this, remove a condensate pipe & drain to a container. I hope that this information will help you.

Potterton Suprima 30 Overheat Stat and Casting Sensor


I have Potterton Suprima 30 and it is showing strange behavior these days. The Boiler is turning itself on even when hot and heating timers were set to be not on. Another black device, underneath the water tank, also seems to be dead which otherwise creates buzzing sound when the boiler is turned on. Restarting boiler is not helpful. Please advise the next action.


Hi Bryce, in such scenario you need to check the overheat stat and casting sensor of your boiler. When a boiler is tripped, located on left side of the boiler, overheat stat will cut the power supply and casting sensor will lockout the boiler. Usually, people get PCB replaced however real fault lies in casting sensor. PCB gets temperature report of heating pipe from casting sensor. A Faulty sensor can result into the pipe to get hotter than it should be and eventually be forcing lockout state on the boiler. This is a security feature to ensure safety so that water does not become unbearably hot. By following these steps, you can test the Casting sensor thoroughly:

  1. Electricity button of the boiler is turned off.
  2. Take a functional multimeter and set the meter range to 20 Ohms.
  3. Place the probing wires on sensor terminals.
  4. At a normal room temperature, around 14 Ohms is the expected reading.

If you are not getting the expecting readings, overheat stat and casting sensor must be changed together to ensure proper function by Boiler.

Potterton Suprima 30 PCB

Hi Folks,

I have replaced PCB to fix the lockout issue, for Potterton Suprima 30 installed roughly 5 years ago. Only after 6 months, it started giving the same problem. Even reset is not serving the purpose and the boiler is in constant lockout state. Please help


Hi Jess, going into a lockout state and not starting is common now a day for Suprima boilers due to the enhanced security check. Water flow plays a critical part here and will lockout the boiler if a motorized valve is closed or water pump fails. A timer controls the valve and overall, the boiler will not work if the water pump is having issues. For testing, if the water pump is working fine, you need to keep boiler off for like an hour. Switch it on and gently touch/tap the water pump body to see verify it is cool. If it is getting instantly hot, it implies that pump is short and replaced to overcome lockout issue.