Brown gel in CH header

[diydave]

Hi. I recently(3 yrs) had my boiler replaced and the system was really thoroughly cleaned with a professional pressure flush. Fernox inhibitor was used on the refill. Ever since, my header tank has suffered a build up (over 6 months or so) of a thick brown gel which floats on the surface and a brown coating on tank/ball surfaces. I have sucked the tank clear and washed surfaces with bleach and topped up with Fernox on refilling header but it persists. The water in the radiators is clear enough to tempt you to drink it and I never had a suggestion of a problem in the 20 years previous to the recent replacement. My installer is as baffled as myself. Anybody seen anything similar?

 

[Burger]

Any photos available of this gel in your f&e cistern (header tank)?

 

[Sharp Point]

Sounds like bacterial algae growing, perfect environment in the water...... dark and warm and wet. You could always add some biocide

 

[Harvest Fields]

Sounds like bacterial algae growing, perfect environment in the water.... dark and warm and wet. You could always add some biocide

Does the tank have a lid on?

 

[diydave]

Does the tank have a lid on?

Yes it does... but very loose fitting and crudely insulated.

 

[diydave]

Sounds like bacterial algae growing, perfect environment in the water.... dark and warm and wet. You could always add some biocide

That's what I thought but its not affected by bleach or mould killer? What biocide would you recommend and can it be allowed down into the system?

 

[diydave]

Any photos available of this gel in your f&e cistern (header tank)?

I've just cleaned it out unfortunately! Initially it was over half an inch thick but now forms a thinner 'lily pad' kind of formation on the surface; the colour of sh*t to put it crudely. Down below the surface and attached to the ballcock there are thin gelatinous 'fronds'.

 

[zzzjim]

Is the tank plastic ,or steel ?

 

[diydave]

Is the tank plastic ,or steel ?

Plastic... and always has been.

 

[Chuck]

So-called bio-films typically contain a mix of fungi, algae and bacteria and can include some nasty surprises such as legionella. As a rule of thumb, take the same PPE precautions you would if you were dealing with human faeces. Use purpose-designed biocide additive as a preventative measure.

 

[zzzjim]

Vegetative slime always seems resilient in warm plastic conditions.
( I might be tempted to leave a 10cm off cut of copper pipe in there .. but it may be an old wives tail)

 

[diydave]

Vegetative slime always seems resilient in warm plastic conditions.
( I might be tempted to leave a 10cm off cut of copper pipe in there .. but it may be an old wives tail)

No harm in listening to the wife!! I'll toss a bit in but with all copper connections, I don't hold up much hope!

 

[diydave]

So-called bio-films typically contain a mix of fungi, algae and bacteria and can include some nasty surprises such as legionella. As a rule of thumb, take the same PPE precautions you would if you were dealing with human faeces. Use purpose-designed biocide additive as a preventative measure.

Sound advice. Can you recommend an appropriate additive... one compatible with Fernox?

 

[diydave]

Many thanks all for helpful replies. Sounds like a biocide is worth a try. Can anyone recommend a Fernox compatible one that can happily be drawn down into the system?

 

[Chuck]

Sound advice. Can you recommend an appropriate additive... one compatible with Fernox?

Fernox do one. From memory, it's called 'AF10' but you should check before buying.

 

[diydave]

Fernox do one. From memory, it's called 'AF10' but you should check before buying.

Thanks Chuck. I'll look it up.