boiler playing up

[sandie1234]

Hello
I have a glow worm flexicom 15hx boiler and a month ago, it showed a fault of 22, I reset it and it worked again, but then went a couple of times again, and showed fault 22, so reset, and showed fault 25, it worked on and off for a month but had to reset it a few times and then it went completely today showing fault 25 flashing. kept trying to reset but back to f25.
called a boiler engineer out and he reckons its the circulation, he went upstairs and said my actuator is playing up but did something and got it working. He said if it happens again I will need a new actuator. what I cant understand is if its not a combi boiler and I need the hot water tank, he said the hot water tank is not connected to anything? yet it was put in 9 years ago and never had any problems before, has it got to be connected for the boiler to be able to work? or is that if I wanted to heat the water tank with the electric switch for hot water if I wasn't using the boiler. is the tank only there because it needs to hold the water to go through for the boiler to heat? very confused as it says you need a hot water tank for the this boiler but yet he reckons its not connected to anything. cant remember now who changed the tank over but only just got problems, so surely it must be connected. Hope someone knows what I'm saying and can help me with this. Thank you

 

[Madrab]

OK - usually a F22 fault is low pressure (but I don't think your boiler has a system pressure switch) and the F25 fault usually means there is a circulation issue but with an open vent the F22 can be a slow temp rise, also pointing towards a circulation issue. Do you have a small black cistern in the loft alongside a large one?

Your boiler is what's called a Heat Only boiler. It only produces hot water that can be used to heat radiators and a hot water cylinder. If you have hot water then the hot water cylinder must be connected to the boiler and may or may not be controlled by a 2 port valve (actuator) and a programmer. Either that or it's being heated by its immersion heater and your electricity cost would be pretty big.

Is the tank only there because it needs to hold the water to go through for the boiler to heat

No, the type of boiler that heats the water when the HW tap is opened is a combi boiler, you don't have one of them and they use the mains water, not stored water. Not sure what your 'engineer' is describing but he's not doing a very good job explaining it if you are quoting him.

To clear things up a few pictures of the boiler and any electrical controls there may be and a few from around the area where the hot water cylinder lives would help.

 

[sandie1234]

Thank you so much Rob for taking the time to help and explain this to me. The heating is still working but not sure how long for as the boiler engineer said it was the actuator, not sure what he did to it to get it working, but he didn't charge me anything, and said it might go again and I may need a new actuator put in, so call him out if needed. I'm not sure how to upload pictures on here. but I have two tanks in loft and one is for cold water and the other is a small one for the radiators. i do have a a 2 port valve actuator and a blue box above that which is very hot. not sure if that is the programmer. would he have meant that the boiler is not connected to electric if I wanted to put the switch down and heat it by using the emersion heater? as the actuator is fed into the boiler, my bills are not high so I'm sure I'm not heating the water that way.
Thank you I do really appreciate you helping me, that's so kind of you.