Chapter 130

Question 1

Ethylene glycol used in glycol coils has a lower:

Answer 1

heat transfer efficiency than hot water

Question 2

If the steam trap is properly chosen and the coil is properly pipe. Steam coils with a short tube length of 1.1 m or less are:

Answer 2

less likely to freeze

Question 3

A glycol velocity of 1.2 to 1.8 m/s is recommended to ensure:

Answer 3

turbulent flow and reasonable heat transfer efficiency

Question 4

Steam coil piping differs from other systems because it usually caries four fluids:

Answer 4

steam, water, air and noncondensable gases

Question 5

In this arrangement the cold air will be entering the coil where the hottest water is flowing

Answer 5

parallel flow

Question 6

even though parallel flow is not as efficient as _________ arrangement, this is one instance where safety against freeze up has priority over heat transfer

Answer 6

counterflow arrangement

Question 7

the purpose of the ______________ used with hot water coils is to close the outside dampers and stop the fan if the flow of waster is interrupted due to pump failure.

Answer 7

flow switch

Question 8

F & T trap (float and thermostatic) steam traps are preferred for use with steam coils operating at?

Answer 8

low and medium pressure

Question 9

The inverted bucket trap is used when the steam pressure is?

Answer 9

higher than 172 kPa

Question 10

What is the maximum temperature rise through a steam preheat coil?

Answer 10

18 degrees celcius

Question 11

A modulating control valve can be used to control steam coils when the entering air temperature is above?

Answer 11

1.5 degrees celsius

Question 12

When choosing a control valve fora steam heating coil, what pressure drop across the valve should you be looking for?

Answer 12

50% of inlet pressure

Question 13

What will a F&T trap (float and thermostatic) discharge continuously?

Answer 13

air and condensate