Central Heating - water gurgle

[Turpin]

Hi,

We are running a Baxi Bermuda 552 behind a Gas fire in the living room, a Grundfos selectric pump (3 speed) on a 2-circuit system with an F&E tank.

After getting a rad replaced with a towel rail, we have a problem - when the system has been off for a long while, there is a gurgling of water sound from around the pump area that sounds like the pump is pushing air as well as water - it clears after about 15 seconds, then is silent and everything runs normally - we have hot water, and the rads (inc the new towel rail) all get hot.

I have done the following to get try and get rid of the water gurgling noise, it's better, but still there and I am concerned it may be hurting the pump in the long run.

• Bled rads - most have no air, 1 upstairs always has a lot, and the towel rail has a lot - I can bleed daily and get air !

• Towel rail is now the highest bleed point

• Bled from bleed valve in airing cupboard - sometimes a small amount of air

• Checked the F&E tank isn't hot - seems ok

• Cleaned the skank out of the F&E tank - water nice and clear

• Checked water coming out of rads when bleeding - looks clear but slightly coloured

• Checked vent pipes at tank - not observed anything coming out, they are cool and not 'wet' inside

• Dropped the pump from speed 3 down to 1 - makes things quieter and still works ok

• Dropped boiler down from 4 to 3.5 on the thermo setting

• Levels look fine in tanks and not overflowing

• Tried bleeding pump from big chrome screw - nothing happened, no air or water ??

• HW has always been set to 50 degrees C to try and avoid scaling[/list
  
  When the towel rail was fitted, the guy had trouble filling it by gravity from the system itself - he had to put water in manually.
  
  I'm running out of ideas. I can take more pics if needed, but here is our layout.
  
  
  
  
  
  Thanks.

 

[bengasman]

• HW has always been set to 50 degrees C to try and avoid scaling

[/b]

That leaves you wide open to legionella infection

If you had to clean out the cistern, it means that your system is full of carp, which needs to come out as well.
Eliminate horizontal pipe runs where possible and -upside down u in pipe at all costs-

 

[Turpin]

That leaves you wide open to legionella infection

If you had to clean out the cistern, it means that your system is full of carp, which needs to come out as well.
Eliminate horizontal pipe runs where possible and -upside down u in pipe at all costs-

Cheers, I'll check the Legionella thing out.

Everything was fine before the towel rad replaced an existing rad, so I think the pipework layout is generally fine.

Would crap in the system cause the 'gurgling' noises like water / air on a cold startup?

My guess is that there is air somewhere that 'collects' once system isn't pumping, then gets shifted in one go, causing the 15 seconds of gurgling. Would that be a possibility ?

 

[gas4you]

Sounds like a blockage in the cold feed where it tees into the cylinder return on your diagram.

Drain off some water and see if f&e tank empties and fills whilst draining.

If it doesn't then you have a blockage.

 

[Turpin]

Sounds like a blockage in the cold feed where it tees into the cylinder return on your diagram.

Drain off some water and see if f&e tank empties and fills whilst draining.

If it doesn't then you have a blockage.

Ta mate, gonna give that a go, if I find it wont refill from the F&E is it a case of cutting out the tee section and replacing (sounds like a real arse of a job) or can I blast out the crap or rod it from the feed itself then drain it through ?

A blockage rather than an airlock in the cold feed yeah?

For reference :-

 

[twgas]

you've got a fully pumped system-no as per the diagram. pos air in primary flow as it rises into cyl coil

probably blockage in air seperator.

andf the elecs should be in a junction box

 

[Turpin]

you've got a fully pumped system-no as per the diagram. pos air in primary flow as it rises into cyl coil

probably blockage in air seperator.

andf the elecs should be in a junction box

Hehe cheers, that will teach me to download the wrong pic wont it ?

The electrics had crossed my mind, we've only been here about 6 months, so am slowly sorting out the things just like that.

Interestingly, I haven't touched a thing for the last 48 hours, and this morning most of the air pumping sound has gone, just a gurgle now when it fires up - 2 rads upstairs are now hotter at bottom than top - top rail on towel rad is hot to touch, the rail below is boiling and you can't hold your hand on it - same story with the rad in the next room. Rest as per normal.

 

[martyc]

Could it not be that since your new rad was fitted that there is a slight leak drawing air into your system?.
Tighten up the compression fittings around the rads that were effected first and bleed.
Marty.