Air rushing round hot water/heating system HELP :-)

[steveorules]

I have a conventional boiler/heating system which has what sounds like air rushing around the system. I've bled the rads, not much air in there, I believe it must be in the hot water side of the system.
I've tried the vent pipe by the side of the hot water tank, just water comes out. Any ideas how i can get rid of the air and stop the annoying rushing sound ???

Many thanks in advance for any tips and advice offered.
Cheers,
Steve.

 

[ianniann]

Hmm, you think it is the "hot water side of the system". I'll leave judgement on that to the experts but it doesn't sound likely.

Whwre is the rushing sound? In the radiators? In the boiler? In the taps? When the heating is off but the hot water on?

Did you bleed the radiators with the heating on or off? Did you try every one? Air usually collects in just one or two of them but not in the others.

By "conventional", do you mean a vented system with a hot water cylinder and a tank in the loft with a ballcock in it?

 

[moggridgeplumbing]

Also has this just started occurring or have you had any work done recently on your CH system? Do you getting any noises from the boiler? Has the pump been changed or it's speed changed?

 

[steveorules]

Thanks for getting back to me guys.

By 'conventional system' I mean it has a boiler, hot water tank, tank in the loft with a ball valve etc etc.
When I bled the rads, the system was off, hardly any air in any of them.
Today i tried the system with just the hot water on and then just the heating on and the noise was there both times ?
You hear the rushing noise through the pump and hear it gurgling at the boiler. Sounds like its going round in a loop. Dont hear it through the rads.
I checked the loft tanks levels, seem ok.
I've not had any work done on the system and the noise has been there for quite a while, just annoying me now and I need to sort it.

Any ideas ??
Cheers,
Steve.

 

[JohnD]

If you bleed the highest rad in the house, does water squirt out, forcefully and without dying away?

When did you last use cleaning or inhibiting chemicals in the system?

What colour is the water in the rads, and in the F&E tank? How thick is the mud in the F&E, and what colour?

 

[moggridgeplumbing]

I'll sticking my neck out here, but I'm thinking blockage in the cold feed from F&E. Do JohnD's rad test and let us know.

 

[flutterbye]

I have something similar after bunging up the overflow and cold feed in the F+E tank to replace a lockshield valve. Its interesting that you reckon a blockage (or an airlock?) from the F+E coldfeed into the heating system could cause this?

Why would that cause the problem? And what would the easiest way of checking that water insn't flowing from the F+E to the system?

 

[JohnD]

this is the quickest and easiest first step in diagnosis

If you bleed the highest rad in the house, does water squirt out, forcefully and without dying away?

When did you last use cleaning or inhibiting chemicals in the system?

What colour is the water in the rads, and in the F&E tank? How thick is the mud in the F&E, and what colour?

 

[moggridgeplumbing]

Come across it loads of time flutterbye. F&E full of water, boiler overheat,no water coming out of top radiators. Oh look they've got an air separator! On investigation is caked in magnetite. Replaced and ran new cold feed - problem solved.

 

[Sparkgap]

Heating pump cavitation? what is the static head at the pump? Is the pump on too high a speed?

 

[steveorules]

Hi chaps,

I bled the highest rad, there was a constant flow of clear water, ran it for approx 30 seconds (not sure if that was long enough ?), did not die off.

I checked the F&E tank in the loft, there was some mud in the bottom but only about 3mm deep, well below the outlet. The mud was dark brown/black ish in colour, fine sediment not thick sludge, water was clear.

Im unsure when or if an inhibitor chemical has been used, definately not in the last 3 years.
Its a 4 bed house and the pump speed is set on No. 2
Heating and hot water both work fine.

By the side of the hot water cylinder there is a vent pipe with a screw top, what about if I open that with the system off and see if the F&E tops up the system ??

Or any ideas on what my next move should be ??
Cheers,
Steve.

 

[ambi]

Is it a condensing boiler?

 

[moggridgeplumbing]

Shame you didn't mention that before! Could be air trapped. Unscrew air vent (AV) until all air released. Don't worry it won't flood the place, unless you unscrew it too far and it drops below the floorboards, then you will have a nice fountain.

 

[steveorules]

I dont think its a condensing boiler ? Its a Stelrad Group Ideal WLx if that means anything to any of you ?

I have tried the AV pipe by the hot water cylinder, and got the fountain that you mentioned !! not much air came out but plenty of water.
Should I open that and let some water out to see if the F&E tank level drops to replenish ???

Cheers guys for your continued help, much appreciated.

Steve.

 

[steveorules]

Guys ???????

Dont dessert me now in my hour of need


Any more ideas ??

Cheers
Steve.