I have a nu-heat UHS installed in 2006. Recently I’ve noticed a dark orange coloured substance appearing in 2 of the flow

[John FA]

Can anyone help me identify the cloudy orange contaminant and suggest a remedy?

 

[king of pipes]

It is corrosion caused by oxygen in the heating system it needs flushing out throughly and a quality biocide chemical treatment added like Sentinel x700 . Kop

 

[Ric2013]

Why is it so much worse on two of the gauges?

 

[Ric2014]

It is corrosion caused by oxygen in the heating system it needs flushing out throughly and a quality biocide chemical treatment added like Sentinel x700 . Kop

Why is it so much worse on two of the gauges?

The left gauge takes 4 litres, the right one takes 2.5 and the middle 2 are much lower flow. I’ve hardly had the system on since I noticed it in case I worsened a problem that might be resolved better if I didn’t. Thank you very much for your comment. Do you have an idea where the corrosion is coming from? The boiler does gurgle for a few seconds after starting up.

 

[John FA]

It is corrosion caused by oxygen in the heating system it needs flushing out throughly and a quality biocide chemical treatment added like Sentinel x700 . Kop

Thank you very much for that reply. Do you know where the corrosion comes from? The oil fired boiler does gurgle for about 4 seconds on initial start up.

 

[John FA]

Why is it so much worse on two of the gauges?

The left flow gauge is set at 4 litres the right one at 2.5 and the middle two only 0.5 and 1 litre. I’ve hardly switched it on since noticing the contamination in case I make it worse.

 

[king of pipes]

Your oil fired boiler is just a steel jacketed box with a burner firing into it, the combination of steel and water and heat without a corrosion inhibitor added will cause rust and sludge to form in the system, your system is long overdue a water change and chemical treatment this should be done every 5 years as a rule Do you have a service agreement ? when was the boiler last serviced ? it is now part of a service to check the water quality and pH level and address any issues found . Regards Kop

 

[Deleted member 123817]

Assuming a sealed system check filling loop, it may be permanently open and making up for some even small leaks which will very quickly cause corrosion .

 

[John FA]

Your oil fired boiler is just a steel jacketed box with a burner firing into it, the combination of steel and water and heat without a corrosion inhibitor added will cause rust and sludge to form in the system, your system is long overdue a water change and chemical treatment this should be done every 5 years as a rule Do you have a service agreement ? when was the boiler last serviced ? it is now part of a service to check the water quality and pH level and address any issues found . Regards Kop

Thanks for the info Kop. My boiler is serviced annually but I’VE never been able to get a plumber very interested in servicing the UHS though items have been changed when they’ve been malfunctioning. The boiler feeds both the UHS and upstairs radiators and I’ve checked that the corrosion inhibitor appears to be okay in the rads and the radiator water shows clear. Sentinel X100 is used but I wonder if this suits both the steel rads and the plastic UHS? Any idea what might specifically cause the contaminant in the UHS without discolouring the rad circuit?

 

[Ric2013]

The suggestion to use X700 as well is that while X100 will work as a corrosion inhibitor, X700 will prevent bacterial growth at the low temperatures found in the UFH section of your system. I'm not sure exactly what that has to do with the rust (on the gauge springs?) however, but I suppose there is the possibility that the brown is some form of bacterial growth.

 

[king of pipes]

This explains it