CENWAT Pipework Sizing and Installation 2

Question 1

What type of fitting is NOT permitted for making joints on gas pipework concealed within walls?

Accepted Answer

Compression fittings

Answer

Compression fittings must NOT be used on gas pipework that is concealed within walls, floors, or where not readily accessible. Only permanent joints such as soldered capillary, brazed, or approved press-fit fittings with gas-specific seals may be used in concealed locations, as compression fittings can loosen over time.

Question 2

What is the minimum fall required on a condensate pipe from a condensing boiler?

Accepted Answer

A minimum fall of 2.5 degrees, approximately 44mm per metre

Answer

The condensate discharge pipe should have a minimum continuous fall of 2.5 degrees, approximately 44mm per metre run, toward the drain point. The key requirement is a continuous fall with no traps where condensate could collect and freeze.

Question 3

What is the purpose of a magnetic system filter installed on the return pipe of a central heating system?

Accepted Answer

To capture magnetic iron oxide sludge (magnetite) from the system water

Answer

A magnetic system filter is installed on the return pipe close to the boiler to capture magnetic iron oxide particles (magnetite) from the circulating system water. Magnetite is a product of internal corrosion and if not removed can block the boiler heat exchanger and damage pump seals.

Question 4

What is the minimum insulation thickness required for central heating pipework in unheated areas under Building Regulations Part L?

Accepted Answer

19mm for pipes up to 22mm diameter

Answer

Building Regulations Part L requires that central heating pipework in unheated areas such as lofts, garages, and under floors must be insulated. For pipes up to 22mm diameter, the minimum insulation thickness is 19mm with a material having a thermal conductivity of 0.035 W/mK.

Question 5

When sizing radiators for a room, which heat loss calculation method is commonly used in the UK?

Accepted Answer

Using the U-value method considering fabric heat loss and ventilation heat loss

Answer

The correct method involves calculating total heat loss from the room, including fabric heat loss through walls, windows, floor, and ceiling using U-values, areas, and temperature differences, plus ventilation heat loss based on air changes per hour and room volume. The radiator output must match the total calculated heat loss.

ACS CENWAT Practice Test

ACS CENWAT Practice Test

CENWAT Pipework Sizing and Installation 2