Draining combi boiler via flow?

[Laggy]

is there anything stopping draining a combi boiler down using the flow pipe as opposed to the more commonly used return?

For example, an automatic valve within the boiler housing itself that closes the flow when there is no CH demand, so the water between the valve and the return inlet would not drain?

Thanks

 

[cross thread]

No reason you can’t use the flow

 

[Laggy]

No reason you can’t use the flow

Thanks!

 

[ianmcd]

You drain it from the lowest point doesnt matter if it is flow or return, have a feeling you are talking about drop feeds , post pics of what you have

 

[Laggy]

You drain it from the lowest point doesnt matter if it is flow or return, have a feeling you are talking about drop feeds , post pics of what you have

Thanks for your assistance, but I’m putting together a pretty comprehensive new boiler install, and I have various accessories on the flow, close and lower than the boiler (deaerator, temp gauge, drain, bottle vent near a big drop to rads then a valve). Idea is I can isolate these bits from the boiler and drop to rads and drain them for convenience.

On the return, I have filter, expansion vessel, manual air vent, extra pressure relief valve with Tundish, pressure reducing valve, temp and pressure gauge, and filling loop that is piped to return and also piped to filter for flushing filter in isolation from everything else. These devices can be isolated from the boiler and drop to rads and drained via the filter too for convenience, but they are situated a bit higher than the boiler.

So I was checking I can isolate the boiler from the return devices, and open the drain after the flow devices, to drain the boiler. I didn’t want to add another drain directly below the boiler on the return (as is normal) if I didn’t need to because then I’d have three drains around the boiler (as well as another at the lowest point of system where the auto bypass is).

So I was just checking there is nothing in the boiler stopping flow through it when the boiler is “dead”.

Cheers

 

[muggles]

Why do you want a pressure reducing valve on the return to a boiler?

 

[Laggy]

Why do you want a pressure reducing valve on the return to a boiler?

Sorry, that’s wrong, I haven’t got one there, it’s on the supply. I was tired last night and reeled too many things off!

 

[Madrab]

Best practice would recommend an external drain on both feed and return pipework.

 

[Laggy]

Best practice would recommend an external drain on both feed and return pipework.

Any reason why you need it on both?