Central Heating Question

Vaillant ecotec831/corrosion/anomalies with entrance of air in the heating system

1*FACT*:
CORROSiON INSiDE THE CONDENSATiON PASSAGE of FLU:

After 2/3 months of installation has been a continuos dripping of orangish from a joint the flu on the top of the boiler.
When flu has been dismantled a large corrosion area was inside the flu, dripping inside the boiler and outside the flu.
After a couple of intervention the external drip has stop, but very likely the installer conceal the internal one.

QUESTiONS on 1*FACT*:
1)Which area of the chambers in the boiler will be affected by this contaminated water?
2)Which side effects can cause?
3)Corrosion extended to other areas and decanting of metal particles?
4)Who is to be held responsible for the defective flu(suggested?Vaillant decline responsability

2*FACT*:
CONTiNUOS ENTRANCE OF AIR in the HEATiNG SYSTEM:

With the start of the cold temperatures i started using the heating.
There has NEVER been loss of pressure in the radiators.
(We can meter this exactly has we have installed gauges on top of most radiators).
However i noticed large amount of air sitting in the only radiator that has not been changed, and large portion of air running trough the system making a loudy whistles.
Air has been flushed twice in 2months,on the second occasion the plumber increased the pressure to 1.5ATM that reach 2.5/3ATM during operation.
With more pressure inside the system the air temporary stopped his entrance for a longer while, but after a month from the pressure increase of the plumber, and the 3 days of absence the air again started his entrance WiTH NO LOSS in PRESSURE.

COMMENT:The remedy of increase the pressure in the radiators has been very likely ordered by Vaillant as the correct operating pressure should be no more of 1.5ATM(all the time)

QUESTiONS on 2*FACT*:
1)Where is likely this air coming from?
2)Why the pressure remain stable after the air entrance?
3)Opinion about my comment on the 2*FACT*?
4)The contaminated water from the flu can be related to this intrusive air?

THANK YOU VERY MUCH for SUPPORT

W.H.

1 Answer

Best Answer

Having fitted Vaillant hand over fist i find your experience surprising. Air or maybe gas (hydrogen)in the rads is a result of POOR installation procedure. You can flush the system until the cows come home, if not done properly the system will still be dirty. Air can enter the system if plastic pipe is used that is not marked as BARRIER pipe. Oxygen can pass in molecular level through plastic. Coca Cola know all about this,Its a big issue for them, as they would lose the fizz over time.
Did the installer use a Vaillant flue kit. Other manufacturers flues will fit, but you should never mix and match.
With the dripping flue, if the inner pipe (plastic) is not shamfered and lubricated with an approved lubrication ( water ) the seal is pushed out or rubbish stops the seal from sealing and it drips.
Vaillant Boilers are good so your issues should be easily resolved.

Pete

Answered 18th Jan 2013

pjb plumbing & heating

Member since 17 Apr 2012

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