I'm getting a F23 fault on my boiler, and somtimes at F28 fault with F54.
Some of the 10mm plastic pipes are completely blocked with sludge or other obstruction.
The property was built around 25 years ago. Previously there was an open vented central heating systems, which was converted around 12 years ago to a combi system with the hot water tank removed.
The boiler is a valiant eco tec.
Since moving into the property 7 years ago I had a few services and the heating worked okay (rads were warm but not really hot)
Last winter we continued to get
The F23 error code on a Vaillant boiler ( indicates a temperature difference between the flow and return pipes that exceeds 35°C.)
The plumber was correct that the boiler wasn't the problem, but that the pipes are sludged up, or there may be another restriction.
The boiler worked fine throughout the summer when we were using it for hot water only.
What I can't figure out, is In the airing cupboard where the hot water cylinder used to be, there are 5no. 22mm plastic grey pipes.
There is one with a stop end which I presume was the hot water.
Then there are 2no. Loops with bleed valves at the top, and there are definitely central heating. 1 gets very hot and the other is Luke warm. I wouldn't expect 2 loops? Unless 1 was for the first floor and the other for the ground floor?
But all rads are fed from the first floor roof void, down to the rads in 10mm plastic.
The plumber but the pink crystals in, which is acid to try and clear blockages. He was here for a half day to keep costs down. This didn't work.
However, at the moment we generally have to reignite the boiler as we have the F23 fault in the morning, and sometimes we have to press multiple times and after the acid treatment this may have improved.
After this I did my own investigations and took off 15 of the 16 radiators and flushed them with a hose on the end. Water was black with black crispy bits in it. I also ran the filling loop to make sure I could get water coming out of the thermostatic valve and valve on other side to make sure it wasn't faulty thermostatic valves.
Rads upstairs get pretty hot, and only 2 rads on the ground floor get hot, another on the ground floor gets warm, and 5 are cold.
I tried bleeding a rad on the ground floor which is completely cold, and took out 3 litres and radiator got warm so suggested to me it is the return pipe?
I also got the plumber to fix a magnet in the airing cupboard as there is no room under the boiler.
I connected a hose to the radiator drain down valve on the ground which was not working and put full pressure it but water did not come out another drain down point to a rad which was working. Which suggests it is blocked?
As a 'hell mary' I've poured 2 bottles of x800 sentinel in the magnet and left. This normally makes the boiler work a bit better and was going to leave for up to 4 weeks thinking there may be a 'sludgeberg' in a heating loop on a return?
Plumber is more inclined to re pipe parts of the system. Just wondered if anyone else had similar experience of this?
( Should be noted that the heating system was extended into a garage extension in copper)
Unfortunately it is hard to trace all pipework. I've looked in floor void with cutting 110mm access inspection, but was trying to avoid taking up laminate floors ( never go down as good as they were in passed experience)
Thanks for reading if you got to this point!
Some of the 10mm plastic pipes are completely blocked with sludge or other obstruction.
The property was built around 25 years ago. Previously there was an open vented central heating systems, which was converted around 12 years ago to a combi system with the hot water tank removed.
The boiler is a valiant eco tec.
Since moving into the property 7 years ago I had a few services and the heating worked okay (rads were warm but not really hot)
Last winter we continued to get
The F23 error code on a Vaillant boiler ( indicates a temperature difference between the flow and return pipes that exceeds 35°C.)
The plumber was correct that the boiler wasn't the problem, but that the pipes are sludged up, or there may be another restriction.
The boiler worked fine throughout the summer when we were using it for hot water only.
What I can't figure out, is In the airing cupboard where the hot water cylinder used to be, there are 5no. 22mm plastic grey pipes.
There is one with a stop end which I presume was the hot water.
Then there are 2no. Loops with bleed valves at the top, and there are definitely central heating. 1 gets very hot and the other is Luke warm. I wouldn't expect 2 loops? Unless 1 was for the first floor and the other for the ground floor?
But all rads are fed from the first floor roof void, down to the rads in 10mm plastic.
The plumber but the pink crystals in, which is acid to try and clear blockages. He was here for a half day to keep costs down. This didn't work.
However, at the moment we generally have to reignite the boiler as we have the F23 fault in the morning, and sometimes we have to press multiple times and after the acid treatment this may have improved.
After this I did my own investigations and took off 15 of the 16 radiators and flushed them with a hose on the end. Water was black with black crispy bits in it. I also ran the filling loop to make sure I could get water coming out of the thermostatic valve and valve on other side to make sure it wasn't faulty thermostatic valves.
Rads upstairs get pretty hot, and only 2 rads on the ground floor get hot, another on the ground floor gets warm, and 5 are cold.
I tried bleeding a rad on the ground floor which is completely cold, and took out 3 litres and radiator got warm so suggested to me it is the return pipe?
I also got the plumber to fix a magnet in the airing cupboard as there is no room under the boiler.
I connected a hose to the radiator drain down valve on the ground which was not working and put full pressure it but water did not come out another drain down point to a rad which was working. Which suggests it is blocked?
As a 'hell mary' I've poured 2 bottles of x800 sentinel in the magnet and left. This normally makes the boiler work a bit better and was going to leave for up to 4 weeks thinking there may be a 'sludgeberg' in a heating loop on a return?
Plumber is more inclined to re pipe parts of the system. Just wondered if anyone else had similar experience of this?
( Should be noted that the heating system was extended into a garage extension in copper)
Unfortunately it is hard to trace all pipework. I've looked in floor void with cutting 110mm access inspection, but was trying to avoid taking up laminate floors ( never go down as good as they were in passed experience)
Thanks for reading if you got to this point!
