Header tank stagnent

[nads1978]

I have a rental property that has a Gledhill Pulsacoil 2000 electric boiler/storage. When I got the property it was weeping from the immersion coils, and one kept tripping the inbuilt overload. I changed these for the expensive units the manufacturer recommends. Obviously to do this I had to empty the cylinder.
The header was stagnant, even though I used an inhibitor, Screwfix own brand.
Now I have filled it again, the water in the header is starting to go stagnant again after only 3 weeks.

Should I use a different brand? Another method? The manufacturer has no technical help other than FAQs - which this is not one.

 

[dcawkwell]

No it is fine.
The water in the system does not get topped up. So will go stagnant.
There should be a cover for the header tank but nothing is wrong.

 

[JohnD]

You can bale out the header tank (it may be muddy at the bottom), wipe it clean and dry, and sponge it with bleach. That will remove or kill some of the growth. Then refill it, and add Fernox Biocide AF 10 which you can get from a plumbers merchant but probably not a DIY shed.

A plastic lid will reduce the amount of dirt, insects and birds that fall into the tank and rot.

 

[nads1978]

Okay, thanks chaps, it's more the smell that my tenant is complaining about.
I emptied it and scrubbed out the header. All the water in the main cylinder came out fresh/clean, so is just the header.

It does have a lid, the lid is fitting properly. There is a small gap around the filling pipe, I'll fill that and, empty the tank and add the AF10.

Cheers nads

 

[nads1978]

I have the AF10 coming tomorrow, should I use an inhibitor too, or does this include inhibitor properties, if I need one, I guess any Fernox one should be compatible?
Cheers Nads.

 

[JohnD]

it is not an inhibitor, just a biocide.

The inhibitor should be added after draining a couple of gallons from the system, so that it is drawn down into circulation during refill; and the biocide should be added after filling is complete, so that it will be concentrated in the F&E which is most prone to bacterial growth. That way it will not get diluted, except very slowly as small amounts move up and down the F&E pipe during expansion.

The water in the boiler and radiators is normally too hot for bacterial growth.

If you have UFH, which is not so hot, or if you get smelly growth in the radiators (unlikely) then half the biocide does need to be mixed into all the circulating water, and the other half stirred into the F&E tank after filling