Plumbers: Radiator Bleeding Problem

[saxon51 10]

And don't overtighten the nut! Council radiators seem to use cheap plastic washers that split easier than they squeeze.

[WallBuilder 10]

Originally posted by Magneteer

Of course you can bleed a sealed system in exactly the same way as you would with a traditional tank fed system. Sealed systems are mainly found nowadays on combi boiler systems, but the air still has to be removed in order to fill it with water ( laws of physics and all that). The only difference is that you have to top it up manually, with water from the main inlet via the filling loop,( a length of flexible pipe usually located near the boiler). When the system is full and all radiators bled, the pressure as seen on the pressure gauge on the front of the boiler should read approx. 1-1.5 Bar. Job done.

 

I've known people with a sealed system open a bleed valve and then just expect the air to come out and the radiator to refill with water. My entire post did read that you had to manually put water into the system to get the desired effect,so I'll retract my earlier statement that sealed systems cannot be bled and instead just say it's not as straight forward as a system with a header tank.

Guess what I'm doing tomorrow?

[1Man&hisBMW 10]

sealed systems can be bled of air, but as pointed out in this thread have to be refilled from a valve near the boiler (usually on combi systems). easy enough to do I reckon, should take you all of 15 minutes. Dont forget to close the valve again after refilling the loop, as thats a fresh water inlet and should not be left open.

[Lurch 10]

Originally posted by 1Man&hisBMW

Dont forget to close the valve again after refilling the loop, as thats a fresh water inlet and should not be left open.

Technically, the filling loop shouldn't be left for an end user to play with. It should be for the plumbers only! I've yet to come across a sealed system that hasn't got the filling loop fitted.

[1Man&hisBMW 10]

Originally posted by Lurch

Technically, the filling loop shouldn't be left for an end user to play with. It should be for the plumbers only! I've yet to come across a sealed system that hasn't got the filling loop fitted.

 

the filling loop is fitted on all combis I have seen, and most manuals instruct on how to fill the loop anyway. the only thing usually missing is the lever on the valve, but most fitters even leave this on. still how much would it cost to have a plumber out to do the job?

[Guest Pauly]

I've come across one or two that have their filling loops removed and metals caps covering the non-return valve, although like you say most of them still have their filling loops attached. It's not too good for the system really as they have been known to pass and then you get pressure loss on your system. Best to keep an eye on it and make sure your cold-setting system pressure is always around 1-1.5bar.

 

And yes, don't leave the tap open on a filling loop. A certain forum member (who shall remain nameless) once called me up saying his boiler was leaking. After attempting to blow some of the pressure off, draining it off and refilling we realised that his other half had been playing around and had left the tap from the cold feed wide open so the system pressure was nearly up to 4Bar. OUCH!