Glowworm condenser developed kettling after 6 months?

[kaytay]

your opinions please, while I wait for the cogs of waranty world to turn.

My 6 month old Glowworm 15HXi has developed a purring/rumbling/ vibrating noise at the top of its temperature ramp up,(like an idling diesel transit at its worst) was lasting for about 3 degrees on the temp readout and about 2 minutes duration. There are no error codes and besides the noise eveything does what it's supposed to.

The Waranty engineer has been and fiddled with it twice in 2 days but off the record thinks the heat ex may have scaled up causing kettling.

my question is How likely is this???
and what has caused it? or could it have been a duff'n from the start

He adjusted a few settings on the PCB on his first trip which didn't affect the noise / operation. He also took a system water sample to be tested for acidity

He replaced the 'gas section' on his seccond trip and further tweaked the PCB settings. the noise now manifests earlier in the cycle and lasts longer but the tank still heats up (and the rads do too when called for)

If they replace the heat ex what else should i expect them to do to prevent this happening again in the future

The oldest component in the system is 5 years old and when the boiler was fitted a full powerflush was done and inhibitor added

 

[corgiman]

if no "in line" scale inhibiter or water softener has been provided then its my opinion that is is highly likely

 

[htgeng]

My 6 month old Glowworm 15HXi has developed a purring/rumbling/ vibrating noise at the top of its temperature ramp up

do you have the little blue benchmark card from the guys that installed the boiler? have a look on it and tell us what is says in the Cleaning/inhibitor section.

 

[ChrisR]

corgiman - this isn't a combi, it's doing it heating rads and cylinder.

 

[Agile]

Lime scale can be deposited from an incorrect commissioning procedure when the boiler was fitted.

The very small amount of lime in the initial fill(s) can be deposited in the HE.

Tony

 

[ChrisR]

But I don't think that would start being a problem at 6 months, unless the system is constantly being topped up.
Perhaps more likely it's full of Everflux, so enough radiator has dissolved to become a problem.

 

[fitz1]

could it be a lazy pump or boiler stat calibration wrong.

 

[kaytay]

Thanks guys

From the benchmark / service book:
the system was flushed with 'hyper flush llamco' (sorry its a scrawl)
inhibitor used 'fernox' (no type stated, just fernox)

A fernox sticker on the base of the boiler stated
CLEANED WITH: 'fernox restorer'
PROTECTED WITH:' fernox protector'

The commisioning powerflush was connected in place of a rad. not the boiler.
thinking about it now, the new boiler was in the circuit while this flushing was done, if its new, its clean and shouldn't need flushing?

Will having it in the circuit have exposed it to everything the flush was supposed to protect it from? hmmm[/i]

 

[fitz1]

flush should have been done before new boiler was installad.after boiler installation system should have been cleansed and drained and then filled up with inhibor added.

 

[corgiman]

corgiman - this isn't a combi, it's doing it heating rads and cylinder.

the word I am looking for is "doh"

thanks for that chris I'll get me coat

 

[Agile]

But I don't think that would start being a problem at 6 months, unless the system is constantly being topped up.

I have been to a warrantee visit on behalf of the boiler manufacturer to a boiler installed a few days before which was very severely limescaled in the primary HE.

The installer had powerflushed the system but had used unbranded "pink crystals" which the local plumbers merchants sell in Southall.

The lime scale deposition had occured from the initial fillings because the 28 kW had been run on heating on a small system without the installer setting the CH demand down to the required 6-8 kW. The boiler therefore comes on at 28 kW and boils the system water for a few seconds until the sensor responds and modulates back.

It was so bad in that case that flakes of lime scale had blocked the system flow switch. Had the installer used a quality inhibitor before running the boiler then that would probably not have happened.

Tony

 

[ChrisR]

I'm surprised, fair enough it won't be for the last time!

Medium hard water might contain 200mg/l of carbonate, so that's maybe 10g in a smallish heating system. Enough to cover 100 cm² 0.4mm thick. Or about two teaspoons of loose flakes.
There you go!