- May 15th, 2018, 11:03 pm
From current BS 6798:2014
Specification for selection, installation, inspection, commissioning, servicing and maintenance of gas‑fired boilers of rated input not exceeding 70 kW net
188.8.131.52 Separate pressure relief valve and condensate discharge pipes
184.108.40.206.3 Diameter of internally run condensate pipe
The condensate drainage pipe connected to the condensate drain outlet on the boiler shall have a minimum internal diameter (ID) of 19 mm, or as recommended by the boiler manufacturer, to promote the clearance of condensate.
COMMENTARY ON 220.127.116.11.3
Historically, the outside diameter (OD) has been used to specify the size of condensate pipe required as this automatically delivered the internal diameter (ID) considered necessary to aid efficient disposal of the condensate. With the advent of European
Standards, plastic pipe manufacturers can now choose to manufacture to a variety of ODs and wall thicknesses, yet the minimum ID requirement to aid efficient disposal of the condensate remains. Hence the minimum ID is now specified as the requirement,
providing the maximum flexibility of choice for the installer.
18.104.22.168.4 Diameter of externally run condensate pipe
Any external condensate drainage pipe shall be increased to a minimum of 30 mm ID to reduce the risk of freezing.
COMMENTARY ON 22.214.171.124.4
When a boiler is to be installed in an unheated location, e.g. a loft, basement or garage, all condensate drainage pipes downstream from the trap or siphon should be considered as external.
A.2 Connection to an external foul water discharge point
Where an external foul water discharge point is used the following measures shall be adopted.
a) The pipe shall be run internally within the building as far as possible before going external. Where the discharge pipe is external to the building the pipe diameter shall be increased to a minimum of 30 mm ID before it passes through the wall. Wherever practicable, for condensate discharge pipe operating under gravity, the fall to the horizontal for the 30 mm ID pipe through the wall shall be greater than the 2.5° required for internal 19 mm ID pipe.
b) The external run shall be kept as short as possible, preferably less than 3 m, taking the most direct and most vertical route possible to the discharge point, with no horizontal sections in which the condensate might collect.
c) The use of fittings, elbows, etc., shall be kept to a minimum and any internal burrs on cut pipework shall be removed to ensure that the internal pipe section is as smooth as possible.
d) To minimize wind chill at the open end of the condensate drainage pipe, the end of the pipe shall:
1) terminate below the grating and above the water level; and
2) be covered by a drain cover such as those used to prevent blockage by leaves.
e) To improve drainage the end of the pipe shall be cut at 45°.
f) The pipe shall be insulated from the point at which it emerges from the outside of the external wall of the building (ensuring no gaps between insulation and wall) using suitable waterproof and weatherproof insulation, e.g. Class O with a suitable PVC or other UV protective coating.
g) The owner of the appliance shall be advised that this type of installation is more likely to freeze in prolonged periods of extremely cold weather (see 6.3.4), resulting in boiler shutdown requiring remedial action.
h) Where there are likely to be extremes of temperature or wind chill, the use of proprietary trace heating systems incorporating an external frost thermostat can be considered, ensuring that the installation instructions of the trace heating manufacturer are followed.
COMMENTARY ON A.2.1
Other cold weather protection methods that are endorsed by the specific boiler manufacturer and/or specific service organizations can be adopted if the method adopted is acceptable to the owner of the appliance, e.g. innovations such as preheating condensate before it leaves the thermal envelope of the dwelling, and blowing warm air down the condensate pipe.
Class O insulation is not UV stable and therefore subject to deterioration when exposed to sunlight. PVC coated versions are UV stable and have added mechanical strength.
since the last bad winters previous-2014 on, vaillant installation refers to the above document for the correcct condense installation.
Working my cohuners off in the back room!
boiler making vibrating noise like kettle|boiler making whistling noise boiler making humming noise boiler making load rumbling noise boiler making gurgling noise.