CH cleanser and inhibitor


What is the best central heating cleanser and inhibitor? I am about to fit a couple of TRV's and will drain the system in the process. Thought, as the system is 10 years old I would flush it and buy some inhibitor for when I refill the system. I see the cost of inhibitor varies in price from around 4 up to 30. Why such a difference? What would you recommend?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.