to flush or not to flush

[mutley racers]

I went to see a job earlier where all the rads are full of sludge and f and e tank is constantly overflowing. The vent does not rise 450mm above the tank as the tank is in the eaves of a loft conversion with no room above for the vent. it literally just rests on top of f and e tank. Now this has been like this for yrs the lady says. All the pipes downstairs are in concrete so am wondering if I should flush it and seal the system or not? The boiler is a 20yr old ideal. So I doubt I can do a combined f and e.

A plumber before me suggested putting in a combi on a sealed system. When I checked pressure and flow, she had 14litres at outside tap but when sink tap was opened went down to 6ltrs a minute. pressure wise she had 5 bar. I checked all the stop cocks i could find to see if any were seized shut but i didn't find. Also, I couldn't find the external stopcock any where. And, there is not much money to put a new main in if needed.

what would you guys do? I am thinking as the boiler is 20yrs old, putting a new ideal+ heat only in with a combined feed and vent if they allow

 

[mutley racers]

Do any od you guys power flush when pipes run in concrete? I have never had a problem with it before but sone posts on here have got me 2nd guessing

 

[Killy Bing]

Combined f&e sounds like your best bet.

Ive never done powerflushing but maybe a flush with a magnacleanse maybe?

 

[mfgs]

I would just do a chemical clean and use a magnacleanse to clean the system and keep it open. I am not a big fan on sealing old systems with the pipework buried in concrete. Is it pumping over constantly? How is the feed and vent currently piped?

 

[Simon F]

check for blockage between fill and vent point

 

[Best]

If the f & e tank is in the eaves, then although the expansion pipe may not be able to rise any higher vertically, - can it not go higher up the angle of the roof between the rafters & back down again? May not cure pumping up issue to just raise the vent & the easiest fix, but not great IMO, is to combine the vent & feed.

 

[mutley racers]

Put magnet and tee at neutral point and it stuck a tiny bit. Feed is behind pump and vent on return. The f and e is buried in the eaves with the smallest little access panel. The only thing I can get to is the ball valve. So I am going to have to cut out all the plasterboard to access it. And yes, its flowing out of the vent constantly

 

[Ermintrude]

It's a mess . Do a pressure test , if it passed seal it, if it fails find leak / you can't leave leak on system . Waste water, conservation of fuel and power and not best practice. I would fit heat only and seal system, if it dosnt work remove expansion and reconnect header.

 

[mutley racers]

It's a mess . Do a pressure test , if it passed seal it, if it fails find leak / you can't leave leak on system . Waste water, conservation of fuel and power and not best practice. I would fit heat only and seal system, if it dosnt work remove expansion and reconnect header.

What do you mean 'seal it and if it doesn't work, refit header'? So don't pressure test just seal it any way? And if it drops, just put on header so it keeps topping up?

what about flushing? Do you guys ever flush when pipes ate in the concrete? So far MFGS says he doesn't

 

[mfgs]

I flush, I just don't powerflush. I use my magnacleanse to clean the system, much less aggressive.

 

[Ermintrude]

No sorry but irratic as busy eating.

1. Pressure test
2. Remedy any leaks

3. Seal system by turning f&e into one blank and an expansion vessel with a built in gauge prv and filling loop.

If system keeps popping then reconnect headder. I would probably do a hot flush and fit a mag.

 

[mutley racers]

I flush, I just don't powerflush. I use my magnacleanse to clean the system, much less aggressive.

Oh sorry, I didn't mean you don't flush, I jusy meant powerflush with concrete embedded pipes

 

[mutley racers]

No sorry but irratic as busy eating.

1. Pressure test
2. Remedy any leaks

3. Seal system by turning f&e into one blank and an expansion vessel with a built in gauge prv and filling loop.

If system keeps popping then reconnect headder. I would probably do a hot flush and fit a mag.

So can you just replace the f and e with an expansion vessel and a prv and gauge and put filling loop in and cap vent where it tee's into system. Or would you alter pipework and put all on return?

What pressure would you test the system to?

 

[mutley racers]

1 1/2 x working pressure so 3 bar? What are most cylinder coils tested to?

 

[Ermintrude]

Yeh go at least 3bar.maybe even a twix too. Expansion works on any part of system. Prv should be unrestricted - I.e no way of isolating it from boiler .

 

[Millsy 82]

I would repipe where the vent enters the system so you have vent, feed, pump. And cap off the vent on the return get up to temp and give it a hot flush get as much crud out as possible then refill with some cleaner then go back in a week and flush it again. I wouldnt powerflush a 20 year old system with pipes buried in the floor or convert to a sealedsystem with out custard knowing the risks of a leak.

 

[mutley racers]

I would repipe where the vent enters the system so you have vent, feed, pump. And cap off the vent on the return get up to temp and give it a hot flush get as much crud out as possible then refill with some cleaner then go back in a week and flush it again. I wouldnt powerflush a 20 year old system with pipes buried in the floor or convert to a sealedsystem with out custard knowing the risks of a leak.

So if you do the close coupled layout can this be with the pump in any position I.e. pumping upwards, downwards and as schematics show, horizontally?

 

[AWheating]

I'd power flush it with a magnet attached, the Pump does not put great pressures on pipework. It will clean out a lot more that a gravity flush with a magnet attached.afterall it's pointless not getting the major amount of sludge out the system, as it's going to be inefficient.

 

[Mike Jackson]

I powerflushed a system with pipe in concrete floors a few years ago. Couple of weeks later the hall was under water. All that was holding the pipes in the floor together was the sludge.

If it's that bad quote for a repipe and pressurise or walk away.

 

[Ermintrude]

Pipes in concrete loose a massive amount of heat. So some times it's more efficient to re pipe .

 

[southcoastboile]

As long as you let the customer know the risks and get them to sign a disclaimer before doing it it doesn't matter.
I use a kamco machine with magnet attachment. It says in the mis that it won't cause a leak due to the design of the pump because it works on flow rather than pressure.

we have a micro bore system to flush today, several rads cold and pipe buried in concrete.
should be fun.

 

[Ermintrude]

How you going to flush micro? On each leg or you got a better method?

 

[southcoastboile]

Not sure I said to the guy not to flush via a rad.
will probably try it from the boiler or pump and if no flow try it via each problem rad.

 

[Ermintrude]

I normally flush one rad back to manifold at a time if it's micro and blocked, Connect to tail and rad then each leg gets a wash along with rad . Prefer to wash raja out and use mag on micro tho.

 

[mutley racers]

Great. Thanks guys for all help. I will suggest a flush but make known the possibilities of a leak.

Can you use the close coupled layout method with the pump pumping in any direction? Like, when is it best to use a h configuration and so on