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12 Cards in this Set

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A flue, instantaneous sink water heat which supplies hot water to a tap in an adjoining room is?




i Not permitted


ii Only permitted when a warning label is attached to the heater that the max continuous usage is 5 mins


iii Only permitted when the rated heat inpu does not exceed 12kw net


iv only permitted if an atmospheric sensing device is fitted as standard

A. Not permitted

The symptoms of scale formation within the heat exchanger of an instantaneous water heater are?


i Increased flow and reduced water temp


ii Reduced flow increased water temp


iii Reduced flow and reduced water temp


iv Dangerously hot water produced

A. Reduced flow and reduced water temp

THe symptoms of dead leg are?




i if the pilot goes out when the hot water tap is turned off


ii the burner will not ignite when the hot water tap is opened


iii the burner remains on for a few seconds after the hot tap is turned off


iv Reduced burner pressure



A. the burner remains on for a few seconds after the hot tap is turned off

Select the statement which is correct for modern appliances in the uk


i Storage water heaters tend to have a regularly high heat input, instantaneous water heaters tend to have a low heat input


ii Storage water heaters tend to have a regularly low heat input, instantaneous water heaters tend to have a high heat input


iii Both storage and instantaneous water heaters tend to have high heat inputs


iv Both storage and instantaneous water heaters tend to have high low inputs

A. Storage water heaters tend to have a regularly low heat input, instantaneous water heaters tend to have a high heat input

The performance of an instaneous water is defined by


i gas consumption measured oven a given period


ii Net effiency


iii Running cost


iv Flow rate and temp rise

A. Flow rate and temp rise

The manufacturers of an instantaneous water heater state hat it can provide 10 litres of water raised by 30°c per minute . If the cold water temp is 7°c and the hot water flow


rate has been adjusted to give a temp of 37°c, how long should it take to fill a 1 litre vessel.


i 2 secs


ii 6 secs


iii 10 secs


iv 20 secs

A. 6 secs

THe water temp of an instantaneous water heater (flue type b11) will typically be controlled by:




i A liquid expansion thermostatic valve


ii Throttling the water flow rate or by a thermostat


iii A modureg fitted to the gas valve


iv A thermistor board sensor

A. Throttling the water flow rate or by a thermostat

The burner pressure of an instantaneous water heater is controlled by?


i A pressure regulator


ii A fixed or adjustable orifice


iii A diaphragm


iv Govenor

A.Govenor

Instantaneous water heaters with natural draught flue systems (A11 B11 or C11) tend to have


i Bi metallic FSD


ii Mercury vapour FSD


iii Thermo electric FSD


iv Flame rectification FSD

A. Thermo electric FSD

The purpose of the venturi is to?


i Generate low pressure when water flows through it


ii Increase the gas rate as water flow rate increases


iii Create a staged ignition of the main burner


iv Ensure rapid closure of the gas valve when the hot water tap is turned off

A. Generate low pressure when water flows through it

11. The purpose of a slow ignition device is to:


i Generate low pressure when water flows through it


ii Increase the gas rate as water flow rate increases


iii Prevent explosive ignition


iv Delay closure of the gas valve when the hot tap is turned off

A. Prevent explosive ignition

A storage water heater is intended to be


i Left on, full on continuously, the water temp being limited to 100°c


ii Left on, full on continuously, the water temp being thermostatically controlled


iii Come on and off as hot water tap is opened and closed


iv To operate during off peak periods only

A. Left on, full on continuously, the water temp being thermostatically controlled