Constant Radiator Bleeding

[Kewat66]

Hi All,

I have an ongoing issue. Cleaned a central heating system out on an open vented system but i am constantly going back to bleed 1 radiator. I have checked all around for leaks to try and see if any areas air could be entering from but all looks fine.
i drained the system down again and added more inhibitor as it was suggested that may be the system was producing hydrogen but keep getting this 1 rad that needs bleeding. All other rads are fine, working really well except this one which is in the top bedroom. The customer is saying each morning they can here the water moving around and there is a lot of gurgling and then the need to bleed.
Does anyone have any other ideas?

thanks
kewat66

 

[helpsy]

Any AAV fitted? Tried shutting all rads down except problem rad ?

 

[Best]

Maybe always did this?
Auto vents on pipes on suction side of pump can pull air in.
Sometimes, I find air just flows around system for days & weeks, only getting to one rad typically & a furthest rad usually also. Only an air catcher like a Flamcovent grabs the air micro bubbles.

 

[jase158]

1. is rad above f and e?
2. is vent 400mm over f and e? or is it going directly into f and e? had this about hundred times
3. did you turn pump up?

 

[Corgiguy187]

Have you checked at the open vent if it's pumping over or sucking in air?

 

[jase158]

oh and in future, cover your backside by telling custard to bleed rads as you are putting fresh oygenated water in and it can take a while for system to push all the air out.
Never change the pump setting, it may quicken the process, you may get home quicker but half the time you will go back

 

[Kewat66]

2AAV on system. 1 in the boiler and 1 next to the cylinder.
Problem radiator is in the bedroom below the f&e.
i have change the AAV next to the cylinder as the old one way leaking but this has made no difference.

 

[Simon F]

so did you test it with a lighter.:83: air or hydrogen??

if it's hydrogen then the corrosion is still happening.
if it is air, then where is it being pulled in??
is it pumping over? leaky valves? not barrier pipe?

 

[spanner]

Bet it's an upstairs radiator.. try
0) tighten lockshield and TRV
1)removing the union on opposite side of bleed er and filling it manually
2) replace union
3)Turn on TRV and lockshield bleeding the wee excess through bv...

 

[kay-jay]

Bet it's an upstairs radiator.. try
0) tighten lockshield and TRV
1)removing the union on opposite side of bleed er and filling it manually
2) replace union
3)Turn on TRV and lockshield bleeding the wee excess through bv...

I fail to see what this would achieve other than wasting time. The op doesnt have a problem filling the bloody thing he has a problem dragging air in. Filling the rad in a convoluted and unneccessarily laborious manner wont make a ha'peth of difference

 

[spanner]

I fail to see what this would achieve other than wasting time. The op doesnt have a problem filling the bloody thing he has a problem dragging air in. Filling the rad in a convoluted and unneccessarily laborious manner wont make a ha'peth of difference

Swore he said this never occurred before flush
Thought this was the best idea if it is inducing and sucking in air from wherever

 

[kay-jay]

Swore he said this never occurred before flush
Thought this was the best idea if it is inducing and sucking in air from wherever

If its draggng air in. Filling the rad a different way wont help. It will still drag air in. If I was the op I would try to ignite the air to confirm it is actually air and not hydrogen.

As to it not happening before it is possible that the sludge in the system (pre-flush) created enough frictional impedance to the circuit that the impelller driven flow didnt have enough umph to drag the air in.