Short cycling until flow temperature reached - error 2967

[Johntheo5]

It is, so certainly not ramping up to 30kw during the on period but the rad output at 18% vs 12.5% for the 55% (22kw) rating means it averaged ~ 44% higher output?.

 

[JonathanM]

Different starting room temperatures?

 

[JonathanM]

It is, so certainly not ramping up to 30kw during the on period but the rad output at 18% vs 12.5% for the 55% (22kw) rating means it averaged ~ 44% higher output?.

I don't see why such a big difference, from looking at the temperatures in the series. First test was only 45 minutes, second one an hour? I'm just guessing here.

 

[Johntheo5]

Yes, correct, will do 45 min for second one shortly.

 

[Ccw71]

The only check I'm able to do no the HX temp sensor is to measure its resistance and check against the specs, which seem fine. Unfotunately there is no way for me to view the actual temperarure figures.

 

[DP]

HI, sorry for the silence on all the helpful posts. Family duties sometime prevent me from accessing a computer.

@DP I was running X400 through the system with a Magnacleanse attached. I only got about a coffee mug full of magnetite. I was expecting worse. I then opened both 2 port valves, drained down from a drain point below the floor and from the magnaleanse until nothing left. I then left open the drain for about 2 hours with the fill running in the F&E tank. I then shut the drain, bleed the rads, ran pump on high speed to eliminate air from the pump. Later, suspecting an airlock I did a lot of rad bleeding (no air) and cracked the nuts on the pump and the two port valves (also no air)

I totally agree with your comments regarding Johntheo5. His knowledge is extraordinary, as is his generosity to share it and help others.

When flushing is carried out like that, water flowing through the pipes to drain point evacuates the chemicals and suspended sediment. The radiators will only be flushed at the base rib to leave water above untouched. There will be pipe runs that will not be cleared. The manufacturers recommend drain, fill, circulate and drain several times to remove most of the chemicals which help suspend the sediment.

The filter is magnetic. It will only catch magnetic particles unless it has particulate filter included in it

 

[Ccw71]

I am considering another shorter x800 clean and flush (following the above procedure) to see if it improves the situation.

 

[DP]

I am considering another shorter x800 clean and flush (following the above procedure) to see if it improves the situation.

800 is a great chemical but not forgiving at all unless a proper flush carried out. If not flushed properly, will kill the pump
I have used 800 often for a quick thorough job.

 

[Ccw71]

Would you say 1hr is enough run time with x800?

 

[Johntheo5]

Yes, correct, will do 45 min for second one shortly.

The original test for 45 minutes gave 17.3% rad output & the first 45 minutes of the 1 hour test gave 15.3%.

 

[Ccw71]

To quote Thomas Dolby "he blinded me with science" (80's pop reference for all you cool kids). What would your recomendations be moving forward? I appreciate all your help, but also that I can't keep you on the hook for this forever. Until I can get to the root of the 2967 cycling problem what do you suggest as the optimum boiler / pump setting.
I'll get in touch with WB tomorrow and see if any if this makes sense to them. Are there any figures you would think are most relevant to pass on? Sadly, as it was fitted on a boiler replacement scheme, it only came with a 2 year warranty, which expired 2 month ago.

 

[Johntheo5]

I would leave/set the pump to the highest setting that doesn't cause pump over/air ingress to the F&E tank, PP3 or CP2. I would set the boiler SP to whatever value allows the boiler to reach it in the shortest possible time as it will then stop cycling once the SP is reached, maybe return the range rating to 55%?.

WB: Tell them obviously the error, 2967, also that you don't have to reset the boiler after it annunciates??, (which may be normal). Also the flow rate in m3/hr, ie 0.9 (15LPM) that you derived from the pump curves, also that you have tried various flow SP values to no avail and whatever you may think yourself is relevant.
They may offer you a reduced repair rate or even better as its only just over 2 years old but afraid (if you tell them) the chemical clean won't help your case.

 

[Ccw71]

I forgot to come back and put an end to this saga. It was a partial blockage of the heat exchanger. Once it was replaced, everything worked as it should. I've now thoroughly chemical flushed the system and replaced all the rads. Fingers crossed that should be enough to prevent any re-occurrence. Thanks for all the help.