Unit 22 - Chapter 97 Flashcards
In a gravity return system the boiler should be placed
Well below the lowest radiator
The piping and heating units of a steam heating system must be so arranged that
Steam can flow freely to all heating units
The Hartford loop prevents water in the boiler from
Dropping below a safe level
All supply and drain lines of a steam heating system must be pitched to
Allow for drainage of condensate
When starting up a steam heating boiler it should be filled to
1/2 of a gage glass
If the water level falls too low during operation of a steam heating boiler the operator should
Shut the boiler down
In the case of radiators and convectors, the main sources of trouble are the
Valves and traps
Finned convectors should be kept free of
Dust
Slow or insufficient heat throughout a building heated by steam can be caused by
Too low a firing rate
Slow or insufficient heat in one or more rooms in a steam heated building can be caused by a
Faulty steam trap
A pressure balancing device that prevents the boiler pressure from forcing the water in the boiler into the return line is called a
Hartford loop
Steam in a two pipe, vacuum return system is supplied at a maximum pressure of
103 kPa
A vacuum pump maintains a vacuum ___ kPa higher in the condensate return system than in the supply main
7 to 10
Causes of insufficient steam supply to the heating units can be attributed to
- improper pitch
- defective radiator valve
- clogging of connections and valve
In all systems, the horizontal steam supply pipes between boiler and heating units are called
Mains
After a steam heating system has been operating for some time, you notice that some parts of the heating system are still cold. Which one of the following could be the cause of this?
Air is trapped in the affected sections
The ___ system overcomes the difficulty of returning condensate back to the boiler due to insufficient static head.
Two pipe return trap system
The two pipe gravity return heating system had the disadvantage that during startup, some steam could pass through a radiator without condensing and could enter other radiators via the return main, thus trapping
Air in the center
In the two pipe vacuum steam heating system, the steam temperature can be varied from
105’C to 55’C
The piping and heating units of a steam heating system must be so arranged that
Air can be expelled for the heating units and piping
When a single main is used to carry both the steam supply from the boiler to the radiators and the steam condensate from the radiators back to the boiler the system is called
The one pipe gravity return system
Which of the following would you not find in a steam heating system?
A cushion tank
When the return main of a gravity return system is located below the level of the water line in the boiler it is called
Wet return
