Heatline Monza 24 error code F20


I have a Heatline boiler,  Monza 24 model, it is about 5 years old and it is showing error code F20. I tried resetting- didn’t help. Pump is not spinning after starting the appliance. Any idea how to fix it fast?



Hi Dan

F20 fault code stands for overheating. First check if the system pressure is around 1.5 bar, if not refill the system. If that is not the case you will need to call a Gas Safe Register Engineer to have a look at your appliance as it may be PCB, pump or one of the fuses.

Heatline boiler, F5 error code

Hi All,

I have a Heatline boiler, and no hot water or central heating. Boiler is displaying error code F5. ANy idea what does it mean and how to fix it fast? Best if I can fix it myself! I have a new born at home, and it really isn’t a good time for a bad surprise like that.


Hi Jim

F5 error code means flue sensor fault, the simplest way is replacing it. Sometimes resetting the boiler helps- but only temporarily, so what I would do in your position is- first reset it and once boiler picks up the functionality call the local Gas Safe Engineer asking him to come and exchange flue sensor. He will come and fix the issue permanently.

Heatline Compact boiler keeps cutting out


I have a Heatline Compact boiler and it is pretty old- almost 10 years old. It worked fine for years, but recently it  keeps cutting out. After each incident I restart and it helps for a while- max couple of hours. After this two led warning lamps are on, I checked what they mean and one is to verify burner ionisation second gas flow. Gas flow should be fine- same for years. Does anyone have an idea what is the ionisation problem about?



Hi Ben

Why don’t you start with the burner replacement then? And if that doesn’t help then maybe PCB is faulty. Really difficult to say. I wouldn’t close the gas supply blockage either. If you are not an expert, better if you call one. It is not easy to work on an old appliance. Good guy will come and after 30 min will tell you what is wrong and if it is worth repairing at all. It may be the time to purchase a new model…

Heatline Vizio 24 not working


I have a Heatline boiler model Vizio 24 and yesterday it stopped providing hot water or central heating. I went to utility room to see what is going on with the boiler and realized that there is a small leak under the boiler (under cold water supply). No error lights, the only light appearing is the power light. Any advice?


Hi Mark

I would vote for one of the two thigns: 1st low system pressure, please check if the pressure is at the 1.5 bar level, if not refill the system. 2nd is overheat status, and that can easily be solved by resetting your appliance. Let me know if that was one of the two.

Heatline Capriz 25 no hot water

Hi Guys,

I have a Heatine boiler, model Capriz 25, it is a bit old but was always working fine. All I really have to do with it was just to call a service guy annually to do the normal check up. Today I realized that there is no hot water. I went to utility room to investigate what is the situation with the boiler and check the boilers functionality while taps are open. So my boiler boiler lights when I open a hot tap, but after few seconds it switches off – it is not enough time to heat the water- so that is why it is cold. Any idea what is the issue and how to solve it fast?


Hi Jack

Is your heating affected or not? If not then maybe diverter valve is faulty and if yes, then probably heat exchanger plate should be replaced. The easiest way to test the diverter  valve is to turn on a tap and feel the central heating flow pipe under the boiler. If it gets hot, its the diverter valve that will need to be replaced. It is not an easy thing so call for a Gas Safe Registered guy rather than do it yourself


Heatline C24 Combi no hot water

Hi Folks

I have a Heatline Combi boiler that is 3 years old (warranty finished couple of weeks ago), and sth very strange happened. 2 days ago hot water stopped working while central heating continue to work perfectly fine. I tired restarting- with no success. Can someone help?


Hi Josh,

There are two things I would check, first simply verify if the hot water system is not dirty at some point, and if yes, clean it. Heatline boilers are very sensitive to the dirt clogging onto the plate of the heat exchanger. Sometimes simple heat exchanger replacement solves the situation.When was your boiler annually serviced?