Flushing using Spirovent flush connector

[Albumen]

I've just fitted a Spirotech RV2 (de-aerator):

http://www.spirotech.co.uk/en/products/spirovent-rv2/

and a Spirotech MB3:

http://www.spirotrapmb3.co.uk

While I was at it I bought their flush connector, at the bottom of the last link.

The body of the MB3 screws off, and the flush connector screws on. So to flush, supply goes on one pipe, waste on the other. Water goes all the way round the system, because the fitting thats on the pipe interrupts the flow and sends it to the two branches. That's how it sends it through the filter.

I'm not going to use any sort of powerflush machine, just mains water running round the system.

I'll be doing the 'one radiator on at once' system.

Question then, do I need to bother isolating the boiler? In fact, I can't can I? Because surely the boiler is part of the the path? Flow and return never meet except through a radiator (hence the thing about the hall radiator not having a TRV, so there's always a path for flow), so as long as there's always at least one rad open I should be OK, yes?[/url]

 

[JohnD]

well I hope you've loosened all the sludge first using a chemical cleaner.

 

[Johnwayne2]

If you haven`t got a combi you may have a loft full of water and no ceilings.

 

[Albumen]

Yes, combo Vaillant ecotec plus 831

 

[Johnwayne2]

I wouldn`t bother buying the extra gizmo , flushing your system using cold main is actually probably more powerful than actually `powerflushing` which has been a bit of a fad over the years. I always found it mostly pointless. If your heating works ok and you are not getting any cold spots at bottom of rads when top is hot I`d just leave it to be honest.

 

[Albumen]

I've already got the flush connector. It was only £30 and seemed like a no brainer, as it just screws on to the same fittings as the other two things.

Yes, I'm only going to do a cold water flush. The CH seems in reasonable nick now. But I had to drain it down to replace a leaking filling loop hose. So while I was at it I put on a proper part L one (?) with isolators on both ends. So can use the mains to put water in via this flush connector.

Just wondering whether the usual advice, to isolate the boiler applies now. I know that's usually the advice for cold water flushing, because otherwise the water just 'shortcircuits' through the boiler. But with this thing I'm the water enters and exits on the same pipe, at the same point. So it's going all round the system and must have to go through the boiler, yes?

 

[Johnwayne2]

If you don`t isolate your boiler there is a good chance that you will over pressurise the system,meaning that if the guage on your boiler hits 3bar whilst you are flushing you`re safety valve or blow off will operate at your boiler, meaning that you may well have to replace it, costing you an unecessary repair.Don`t mess with things you don`t understand,it`s not as simple as running water through your system.

 

[Albumen]

Thanks for the caveat.

Not sure I understand the problem. I'll be monitoring the pressure, so won't allow the pressure guage to get as high as 3 bar. It's on the front of the boiler, where the isolator valve for the cold supply is. So I'll be watching it just as carefully as I do when I've drained and refilled my system.

The procedure here:

//www.diynot.com/forums/viewtopic.php?p=253454#253454

seem to imply that the pressure guage is on the return side of the boiler. Is that always the case?

But the clear warning there is that because THAT method involves isolating the boiler there will be no pressure gauge on one of the flush directions.

I can fit the flush connector on either return or flow, as there's a filter on the return and a de-aerator on the flow. The flush connector fits onto the same base connector as those two things.

Wherever I fit the flush connector I can still reverse the flow (swap the hoses round), and if the boiler is open all the time then the pressure gauge will still operate, won't it? Or have I misunderstood that?