Boiler fault message - what's it mean?

[Goldspoon]

Have waited over a week now for person who fitted boiler to "drop in" so asking here to see if anything I can do... or I will have to get Yellow Pages out and am a bit skint.

Boiler is a Gloworm Extrafast 120 fitted 5 years ago. Three new radiators recently fitted but boiler problem shown below has been happening for long before this (but now gradually becoming more often until now almost daily).

Basically when we put the hot water on it "sometimes" cuts out and we get a flashing error message "14". This happened this morning even though CH not on so it's nothing to do with CH being on. I can let it cool down and press the reset on a thermostat to get it all going again but it is happening more and more often.

Message 14 means, according to manual: CTN2>97 degrees

Now this suggests to me that the thermostat on the 22mm pipe (the one I press to reset) is getting to 97 degrees and shutting everything down (otherwise water turns to steam and expands x 1600 and blows our kitchen into the next village). So is worrying. The pipe is extremely hot to the touch (i.e. can tap it but would not be able to "touch it" properly. This morning there is lots of grumbling and gurgling coming from inside boiler.

Also water drips outside through a pipe all the time at approx. 50ml per 10 mins (pressure in heating circuit does not drop and never does).

Weird thing is - looking at the boiler diagram - this thermostat (called an "overheat safety thermostat") is on the heating pipe and it is this pipe that overheats... but we only had the hot water on this morning? Looking at the boiler diagram the hot water goes through a completely different part of the boiler than the heating (has its own path through a domestic heat exchanger).

Any thoughts?

 

[Rob]

Circulation problem.

If your heatings working then blockage in the HW circuit i.e plate heat ex.

If no heating then pump is most likley the culprit.

 

[Agile]

If water is dripping from the PRV vent then either there is a serious fault inside the boiler or more likely you have not turned the filling valve off properly.

You can check that by removing the flexible filling loop and see if water comes out of the supply end.

The loop is meant to be removed when not in use for filling under the water regulations.

Tony

 

[Goldspoon]

Thanks. I am betting on the serious fault myself!

Surely if filling loop not turned off properly then pressure would just keep climbing and it does not. It is set at 1.0 bar and rock solid.
??

 

[Agile]

If the filling valve is leaking at the same rate as the PRV is dripping then it reaches equilibrium at some pressure like one bar.

And before you ask, dirt on the PRV seat is why its leaking at 1 Bar!

The supply source leak is why the pressure is not falling.

To go on a little further, all that new water coming in has rusted the rads and that dirt is blocking the secondary heat exchanger causing the excessive temps.

Tony

 

[Anybody]

You must just have the user instructions or perhaps just old instructions. I found the following info in the MI's


Type of fault :-

TEMPERATURE LIMITER.
CONTROLLED BY THE
HEATING THERMISTOR
ON FLOW PIPE.

Possible cause:-

• CHECK HEATING THERMISTOR (MAY BE UNCLIPPED) OR
THREE WAY VALVE FAULTY.
• FAULTY PUMP.
• LOW HEATING FLOW RATE.

 

[Agile]

Two site experts have already pointed to the plate HE as the most likelt cause of the problem but "Anybody" still thinks the MI are a better place to see the cause listed!

Manufacturers dont list faults caused by dirt in the system because they dont add dirt and all systems have to be cleaned before a boiler is fitted.

Unfortunately we have to work on systems in the real world where most people dont flush the system properly.

Last week I really had to push an ex-trainee to take out the plate HE because he had power flushed the system and fitted a line strainer.

I knew that it was blocked from the symptoms he described but he was amazed when he saw all the dirt !!!

Tony

 

[Goldspoon]

If the filling valve is leaking at the same rate as the PRV is dripping then it reaches equilibrium at some pressure like one bar.

And before you ask, dirt on the PRV seat is why its leaking at 1 Bar!

The supply source leak is why the pressure is not falling.

To go on a little further, all that new water coming in has rusted the rads and that dirt is blocking the secondary heat exchanger causing the excessive temps.

Tony

Have disconnected filling loop and it is not letting by. So 100ml of water, per two mins (e.g. 1L per 20 mins) is dripping from a pipe that goes from the boiler to a drain outside through the wall. The water is clear and clean and does not include inhibitor (inhibitor added a few days ago to circuit).

 

[gasgeezer]

prv is leaking probably the dhw one {blue one} f14 is plate heat exchanger blocked as correctly diagnosed earlier.Reccommend replacing both.

 

[Goldspoon]

Thank you...