Fernox cleaner and inhibitor....is my system indirect?

[FooManChu]

Hi

I did a search first on this forum to see if I could find the information relating to my request but nothing seems to fit what I am going to ask.
I am looking for advice on whether I can add Fernox inhibitor and cleaner into my central heating system.
Its an LPG system boiler with a Heatrae Sadia Megaflow cylinder downstairs (i.e. both at the same floor level). As far as I can possibly see, there are no header tanks whatsoever connected to the cylinder and the loft space is restricted and currently has no access. The instructions that came with the megaflow explain how to re-charge the separating bubble so I'm thinking its like a primatic setup? In which case, according to the instructions of the Fernox stuff, it could be an indirect setup and therefore I should not use Fernox in it? I am even remotely close with that hypothesis? To add to this, on the side of the Megaflow cyclinder there is a plastic cover with a single cable coming from it and the cover sticker mentions that this is where the Indirect Thermal Controls are? It is fitted with a Magnaclean magnet device which is cleaned regularly.

Any structured advice appreciated. Thanks

 

[dilalio]

Sealed or vented, heating circuit needs inhibitor. Which one depends on those accepted by boiler manufacturer but top 3 or 4 are usually accepted. Look it up in your boiler MI's.

 

[FooManChu]

@dilalio Thanks. I forgot to mention the boiler make and model. Its a Vailant Eco tec plus and it does mention Fernox 1 and 2 for permanent agents allowed into the system along with Sentinel 100 and 200. And also Fernox 3 and Sentinal 300 and 400 for cleaning measures requiring a flush afterwards. But do I not have to take into consideration when the Fernox instructions say "Do not use with single feed indirect systems"? I'm still not sure if I have one of those prohibited systems or not.

 

[dilalio]

You have a Megaflo, which is an "unvented" indirect cylinder hence no F&E tank in the loft. The expansion of DHW is handled by the air bubble within the cylinder. CH expansion is handled by an EV within the boiler (if system or repurposed combi) and MAY have an additional external EV.

Use of inhibitor is fine.