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Rick Ridley
Rick Ridley, UK Heating Engineer
Category: HVAC
Satisfied Customers: 2708
Experience:  Retired But have had 30 years on the tools, Ex CORGI
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I HAVE A VIESSMANN VITODENS 100-W BOILER AND JUST DRAINED MY

Resolved Question:

I HAVE A VIESSMANN VITODENS 100-W BOILER AND JUST DRAINED MY SYSTEM DOWN TO REPLACE A RADIATOR. WHEN I REFILLED THE SYSTEM AND BLED ALL THE RADIATORS THE BOILER WAS POWERED UP & CH STARTED BUT CYCLE STARTED. THE FLAME CAME ON AND PUMP STARTED BUT AFTER ABOUT 4 SECONDS CUT OUT LEAVING THE PUMP RUNNING (SAME WITH THE HOT WATER CYCLE). I HAVE DRAINED AND BLED SYSTEM TWICE BUT WITH SAME RESULT. THE PUMP SEEMS TO MAKE MORE NOISE THAN USUAL. IS THIS AN AIRLOCK IN THE BOILER & HOW DO I CLEAR IT. OR WHAT ELSE COULD IT BE?

RGDS GERRY WARING

PS THE BOILER WAS INSTALLED 18 MONTS AGO.
Submitted: 4 years ago.
Category: HVAC
Expert:  Rick Ridley replied 4 years ago.
Hi Rick here UK plumber, yes you have an air lock in the system, the boiler manual air vent inside the casing at the top rear so check this first, Rick
Customer: replied 4 years ago.

HI RICK

 

THIS DID NOT CLEAR THE AIR LOCK, ANY OTHER SUGGESTIONS?

 

GERRY

Expert:  Rick Ridley replied 4 years ago.
this depends entirely on the pipe layout of which I can have know knowledge, if there are any high points then these should have vent points on them, typically the top pipe on the cylinder coil, but with this boiler there will need to be CH vent points as well if any CH pipes have high points not addressed by radiators, but pipes can go up and down under floors causing air traps, these can be difficult to shift, set the pump on high speed and select heating only for a while then HW only alternating until it clears, Rick
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