OK so it looks like X800 is the way to go. Just a couple of things. There seems to be conflicting opinions on how long to leave it in the system so....... how long? I'm presuming it's best to circulate at highest pump speed and have also read to close off all but one rad at a time. Is this the case? If I do have sludge will it remove/suspend this as well as products that are specifically branded as sludge removers? (i.e F3 and X400) First drain and refill the entire system with plain water. For optimum results the entire system, including drop feed radiators where fitted, should be completely drainable. Preferably, full bore gate valves with hose connectors should be provided temporarily for this purpose. Motorised and thermostatically controlled valves must be set so that no part of the system is closed off during cleansing, or rinsing. Discharges must be made to the foul drain and not the surface water drain. For open vented systems add Cleaner F3 via the header tank. For sealed systems add via a suitable dosing point, or use Fernox Cleaner F3 Express 400ml. it can go on the return pipe, to the boiler, so it has the chance to catch detritus before it enters the boiler, with no other components (radiators or cylinder) between the filter and the boiler. That's why it shouldn't go on the flow pipe. Connect the mains water supply, overflow and dump discharge pipes, ensuring that all isolating valves are

Cleaning a central heating system using Fernox F3 Cleaner and protecting with Fernox F1 Protector can restore and maintain system efficiency, resulting in a gas saving of up to 15% every time you heat your room. This saving is equivalent to 110 Kg CO2e per typical home per year.”* Slightly open both the dump valve and the mains inlet valve. Ensure the dump pipe is discharge into an appropriate waste drain. Which cleaner is easiest and safest to use that i can just run, drain and then refill. oh and which inhibitor should I use? Turn the Powerflow unit on to carry out an initial flush to remove the system water. Refill with fresh water and dose the machine with Fernox Powerflushing Cleaner F5. Circulate the cleaner (whilst theheating is on, if possible) and begin dynamic balance flushing (reversing the flow periodically).With the Fernox F5 where is the sludge going to end up? Exactly! You need to rid the system of the 'sludge' not push it around the system! I am concerned at the term "heavy duty" in the title of this product. As it seems to be stronger than the X400 can it lead to stress and leaks at any weak joints or is this not the case as it is meant to be non-acidic? Gradually open the dump valve further, balancing the increasing flow from the mains inlet. Aim for the maximum discharge rate that can be made up by the mains water supply available. Continue circulation with the powerflow throughout. Cleaner F3 is an effective, universal pH neutral, non-foaming liquid cleaner, which removes sludge, scale and debris from existing central heating systems to restore heating efficiency and eliminate boiler noise. When commissioning new systems in accordance with BS 7593:2019 regulations and best practice, Cleaner F3 is ideal to remove flux residues and other installation debris to help extend the life of the boiler and the efficiency of the system. It is suitable for use when powerflushing to accelerate the cleaning process in existing and contaminated systems. Cleaner F3 is a non-hazardous product which is compatible with all metals commonly used in heating systems, including aluminium. I think it'll have to go near the pump - there's definitely not enough room for it on the return pipe at the boiler (not with easy access anyway).

Find a Plumber Plumbers Looking for Work - Post Here Looking for a Plumber? Post Jobs Here Looking for a Heating Engineer? Post Jobs Here Find a Renewable Energy Specialist Plumbers Directory Listings The powerflushing machine can be connected to the system using TF1 Flushing Adapters which can be used where a Fernox TF1 Filter is installed. Alternatively, it may be connected across the flow and return pipes at the boiler (which is particularly useful when replacing a boiler), or you may also connect the machine across the circulator pump using a Powerflow Pump Head Adapter. Finally, you may connect the machine across a radiator, however this option should only be used if no alternative connection point is available. An additional or repeat dose of Cleaner F3 may be necessary in some cases. Drain and flush thoroughly, at least twice, until the water runs clear. When using Cleaner F3 with a powerflushing machine, cleaning should be completed within an hour. Use dynamic flushing with plain water until the water is clear. Refill the system adding Fernox Protector F1 for long term protection against corrosion and limescale. In single feed indirect cylinders, e.g.’Primatic’or similar, potable water chemicals must be used.Look on Youtube, might find a better video, also adding Sentinel X900 is a good idea after you have cleaned out the filter. It is non-aggressive and not acidic like some of the faster cleansers. If you forget to drain it out, it doesn't do any harm (but it will lose its power and the dirt will re-settle after about 4 weeks). Before beginning the flushing process you will need to ensure the system is correctly set up to use the Powerflow unit. Removes sludge, limescale and other debris to restore energy efficiency and extend system and boiler life

I don't have much room to fit it in near the boiler - presumably it could go on one of the 22mm pipes in the airing cupboard instead?

A single dose of Cleaner F3 treats a larger sized property with a heating system of 130 litres, up to 16 radiators, or 250 sqm of underfloor heating. Additional/repeat applications of Cleaner F3 may be necessary for larger systems, or if systems are heavily sludged. Alternatively, Power Cleaner F8 may be used for heavily sludged systems. for inhibitor i use calmag its really good and at 4.95 plus vat per litre its good value. and it carries the ciphe endorsement The TF1 Omega Filter out performs other filters of its size by collecting significant quantities of system contaminants, and competes with many larger filters thanks to the cleverly designed internal mechanisms of the filter. Fernox Cleaner F3 can also be used in conjunction with a powerflushing unit. In this case, please refer to the unit manufacturer’s instructions. When pre-commission cleansing new systems, Fernox Cleaner F3 should be circulated for a minimum of one hour at normal operating temperature. For cleaning existing systems, sludge and debris should be dispersed also within one hour at normal operating temperatures. However, to remove hardened iron oxides and limescale, the cleaning time can be extended to up to one week under the normal heating cycle. If a radiator still has a cold spot after one hour, increase the flow through the radiator by closing the valves on the other radiators.