Grant Vortex Mk2 frozen/blocked condensate water pipe


My one-year-old Grant Vortex Mk2 boiler’s condensate water pipe is chocked. I doubt that it is due to cold weather or some blockage. I have restarted it but did not work. Please help.

Thank you so much


Hi Frank, most of the boiler owners face this issue during extreme weather conditions. Well, do not take tension as you can try different things to solve this matter at home. Firstly, you have to locate a blockage in the condensate pipe. After locating it, thaw the blocked or frozen pipe by simply putting the hot water. However, never use the boiling water, as it will damage the pipe. Lastly, restart or reset your boiler by pressing a button.

Grant Vortex 26 Boiler shuddering sounds

Hi Guys,

I have a Grant Vortex combi boiler, which is almost four years ago. The hot water & heating works well but most of the times boiler make the loud shuddering sounds. My home shakes due to these sounds. I am worried because it seems very dangerous. These shuddering sounds last for thirty seconds to almost 2 minutes & then complete silence. I need help and solution on urgent basis.

Thanking in anticipation


Hi Robert,

It is considered as the most obvious & common problem in the boilers. These shuddering sounds from the boiler are generally caused by the sludge or air buildup, extremely low pressure of water. You can solve this issue at home by simply power flushing the water pipes & bleeding the radiators. In case the problem persists, go for expert advice & assistance.

Grant Combi Boiler Burner not igniting

I have installed my Grant Combi Boiler one year ago. It worked well but currently my boiler’s burner is not igniting though, electricity and oil are present at boiler’s burner. I have taken all the necessary actions but still, burner is not igniting. I hope someone will help me.



Hi Mike

It is a common problem in all types of boilers. Some possible causes are as follows:

  • Fuel supply is not present
  • Empty oil tank
  • Faulty burner
  • Closed fire valve
  • Blocked flue line filter
  • Air locked supply line of oil
  • Extreme combustion air

Do check the above-mentioned things & take the following actions according to your issue

  • If fuel supply is not present then, you have to check the tank & refill it if required
  • If you feel that oil tank is empty then, check & open regulators if required
  • In case of the faulty burner, reset the air damper of burner & check combustion
  • Fire valve can be opened by cleaning it

You can consider this information; if your problem continues, do call a boiler specialist.

Grant Vortex Combi Boiler Overheat Thermostat

My Grant Vortex Combi Boiler’s thermostat is giving wrong readings. Moreover, I am noticing that the thermostat is inaccurate & water temperature is different from that is being shown on the thermostat. Has someone faced this issue? If yes, then please guide me.

Thanks for your kind help


Hi Liza, all electrical equipment develops various faults with the passage of time & a thermostat of your boiler is no different. Thus, if your boiler’s thermostat is giving wrong temperature readings then, it is obvious your boiler will give you a tough time. If the boiler is very old like more than two or three years, then thermostat might have deteriorated & you have to replace it. There are no sudden fixes regarding faulty thermostat therefore, I would advise calling an expert boiler engineer to repair or replace the thermostat if required.

Grant Vortex 26 Combi Boiler burning smells

Hello Everyone,

I have a Grant Vortex Combi Boiler, which I bought three years ago. Now, it gives a very bad burning smell when I turn it on. I wanted to know that if it is something dangerous & how can I rectify this?



Hi Euan,

This problem is quite disturbing, but most of the boiler users face it. This is particularly common in oil or gas-burning boilers because the pilot light of the boilers can collect residue easily. In case, this residue begins to ignite, it can cause this burning smell. I would like to share that cleaning the boiler’s burner can remove all these remains, which can stop this burning smell. On a save side, do contact a boiler engineer in order to have a detailed look at your boiler.

Grant Combi MK2 faulty air pressure switch

Hi All,

My Grant Combi Mk2 Boiler works well until I went away for three days. When I came back & switch on the boiler, it does not ignite. After constant tries, it fires eventually. I have replaced a circuit board, however I am facing the same issue again. Apart from this, sometimes it cycles off & on randomly. What is the problem & how should I address it?

Thanks a lot , Ian

Hi Ian,

I guess it is due to a faulty air pressure switch but it is vital to note that airflow of any type can cause an air pressure switch to not let your boiler to fire. However, it does not mean that air pressure switch is a culprit. For example, your boiler can also not fire due to broken PCB, faulty fan and the blocked flue. When your boiler’s air pressure device has wiring problems, it is possible that its communication with a PCB would be intermittent. As a result, your boiler will cycles off & on occasionally. On a safe side, it is better to call a Gas safe engineer to address the problem systematically.


Grant Vortex Combi Boiler no hot water but radiators are hot

Hello All,

I bought a Grant Vortex Combi boiler five years ago due to its high-class performance. Well, it is quite true but now whenever I turn on the tap or shower, I did not get the hot water. I have checked the radiators. They are getting hot but the water is cold. What should I do in order to get the hot water?



Hi Rob

If your Grant Vortex Combi boiler is not providing you with the hot water but, radiators are hot then, the possible causes are poor mixing valve, dirty coil, and hot water in the boiler being overdrawn, bad aquastat control. I would suggest you contact an expert boiler engineer in order to rectify the problem.


Grant Minor Boiler is not starting

Hello Everyone,

I want to share a strange problem regarding my Grant Minor boiler. My boiler is not starting after various attempts since yesterday. What could be a reason behind it? Should I buy a new boiler as this boiler is seven years old? Please share your expert advice.

Thank you so much



Hi Bill, this is a common problem with grant boiler series. The possible reasons are as follows:

  • Electrical supply is not present
  • Overheat sensor has operated
  • You have switched on the check controls & now they are calling out for heat
  • Low – pressure safety device is activated

If you feel these reasons are causing this issue then, you can take the following actions

  • Refill the system to recommended 0.5 to 1.0 bar
  • Set the thermostat of your boiler to maximum
  • Do check for the 230 volts at the terminal block of boiler
  • Check boiler’s off/on switch. The boiler has to be “ON”.

I hope that your boiler will start after taking the necessary actions.

Grant 90 V3 boiler single bang while firing up

Hello Guys,

I have bought my Grant 90 VE boiler four years ago. All well until last night, but the early morning I have observed that boiler made a single bang while firing up. I tried every possible thing but nothing works. Someone, please help me.

Thanks in advance


Hi James,

If your grant boiler is making a single bang while firing up then, it is possibly due to a delayed ignition. When the gas boiler gets a call for immediate heat throughout the normal operation, a gas valve of the boiler opens & discharges a small quantity of gas into the sealed combustion chamber through small jets. After this gas is ignited by, a pilot light & the flame of jet heat up the heat exchanger. The boiler uses this heat exchanger in order to heat water. However, in your case, gas, which is sent into a combustion chamber, does not ignite instantly. As a result, gas builds & builds inside a combustion chamber up until bang. Eventually, pilot light ignites all the gas thus causing a small explosion. I would suggest you call an expert boiler engineer immediately.

Grant Vortex Combi Boiler getting hot water just for few minutes


I have installed a Grant Vortex Combi boiler two years ago. My experience was good but from last two or three days, I am facing a strange problem when it comes to hot water as I only get it just for few minutes. It is quite frustrating in this cold water. Kindly, guide me on this matter.



Hello Tom, do not worry, as this problem can be resolved easily. Some common reasons along with their possible actions are as follows:

  • Your boiler’s burner is not firing up properly for the hot water


Do check burner’s operation on the central heating

Check working of the diverter valve

Check proper electrical continuity of boiler’s thermostat & burner microswitch

  • You have set extremely low burner’s oil pressure at your boiler’s oil pump


Check & set boiler’s oil pressure for correcting valve

  • You have fitted an improper oil nozzle to your burner


Do check & fit an appropriate nozzle

I hope this information will help you a lot in resolving your problem regarding boiler.