Draining CH system or only adding inhibitor

[Helg]

have not drained/flushed out the CH for 26 years - is it enough to just add some inhibitor or is it worth doing a full drain job?

 

[Armo74]

If you haven't had any problems with rads not warming up or system noise i would just drain at a warm temperature and add inhibitor.

 

[Helg]

tks Armo, but what is the diff between warm draining and complete draining? price diff quite high as it requires two people to do full drainage and also most of the day, checking radiators etc. As simple adding of inhibitor also costs a bit (2 hours+material) I thought I might go the whole way, rusting of pipes is my main concern as they are old pipes

 

[Armo74]

It still mean's a full system drain, i just find that if the system is ran and left to cool for a while the temperature makes the build up of sludge deposits more active and looser(some may disagree). It may be worth your while adding some sentinel x400 and leaving it to run in the system for about 4 weeks and then drain and add inhibitor. Depending on what system you have you find that open vented systems are more prone to corrosion. Like i said in my previous post if you are not having any particular problems the x400, system drain and the adding of inhibitor should be sufficient.