Drain cock and corrosion protection All aspects of plumbing questions and answers, help, tips and information

[chris_on_tour2002]

Hi,

Just finished fitting my new heating system, bloke coming to do the boiler next week. A quick easy question - should the drain cock be on the flow or return? I believe its the return.

Also can anyone recommend a corrosion inhibitor suitable for use in a fully direct system? I've bought 'Aqueous Logic' inhibitor but it says no good for fully direct systems.

Thanks,

Chris

[marrtin]

The drain tap can be fitted in either the flow or return.

You cannot put inhibitor in a direct system as it would be gone within the first day. Are you sure it is a direct system??

[chris_on_tour2002]

thanks for that marrtin, have fitted it on the return as it has easier access.

i think its a direct system - its a WB 28i Junior Greenstar condensing combi so the heating will be pressurised. the hot water will come direct from the boiler, no hot water tank. if i understand it this is a fully direct system, though i am happy to be corrected.

[marrtin]

No. The combi has a heating circuit totally separate from the hot water and is filled by a flexible filling loop So is in effect an indirect system.

I guess the inhibitor you have will be just fine. Just remember to flush the system thoroughly first to remove flux and debris.

[chris_on_tour2002]

so what constitutes a fully direct system? one where the hot water and heating are on the same circuit? would this mean that the hot water passes through all the rads before coming out of the taps?

[marrtin]

Yes. You've got it.