How long can Fernox F5 stay in for?

[brooky_agb]

Hi,

We have just had a new Worcester Bosch External Heatslave 20/35 fit. It's been a nightmare. They said it would take two days and it took a week. We had no hot water and later we eventually got the plumber back to find it had been wired wrong. That now works.

Fernox F5 has been in it for two weeks now! It's a sealed system. I've been pushing the plumber and he has told me that he needs to start the process all over again. He said he would come today and he hasn't!

I'm going to New Zealand for three weeks on Wednesday and it looks like the radiators will have the fernonx F5 in for five weeks on total now at the minimum although the heating will not be on whilst the house is empty. It just can't be drained and flushed again until we are back. I'm really ****ed off as I wanted this done and dusted before we left. Its now going to be at the back of my mind whilst I'm away.

What the hell can I do? Is there any harm keeping Fernox F5 in that long?

 

[crockett]

That cleaner is a powerflushing cleaner, so I would imagine it should only be in for as long as it takes to powerflush, i.e. a day. Someone else may say its fine to leave it in, but powerflushing agents tend to be stronger than usual.

 

[brooky_agb]

The bottle say to keep it in 7 days max I think. I'm worried it is bad to keep in too long. I'd flush it myself but I don't know how. We had a vented system before and I knew how to flsuh that but sealed I have no clue about.

Its frustrating, its cost around £3,500 for the boiler with fitting and I'm having to fight with the installers to come and finish it off.

 

[crockett]

Firstly, switch off the power to the boiler. Find out where all of your draincocks are on your system, stick a hose on each one in turn, open them up, go to the filling loop on your central heating system ( could be near the boiler, could be elsewhere ), connect it up and open it a little to let fresh water into the system, whilst the water is draining. Shut the filling loop valve off, close the chosen draincock, remove hose and move onto the next draincock, repeating the procedure. Once the water runs clear ( 5 mins or so for each bout of draining ), move on and repeat, etc. until all draincocks have been flushed through as best as you can. This should get rid of the majority of the cleaner, but I would advise you to add some inhbitor as soon as you can after this to protect the system from sludge, etc.
If you aren't confident in doing this, get someone in who is, as other problems can arise, such as draincocks that will open but not close without dripping, or ones that will not open as they are old.