4BE3.5 U3 C4 Obj 4

Questions and Answers

EASY What is the purpose of a pressure or altitude gauge in a hot water heating boiler?

To relief excess pressure

To measure the temperature of the water

To control the fuel supply to the boiler

To indicate whether the system is full or not (correct)

What is the requirement for the cock on the pipe near the pressure or altitude gauge?

It must be placed on the pipe far from the gauge

It must be perpendicular to the pipe when closed

It must be removed when not in use

It must be parallel to the pipe when open (correct)

Why is a siphon not required between the gauge and the boiler in hot water service?

Because the system generates steam

Because the boiler is always full of water

Because the gauge is not connected to the boiler

Because hot water boilers are completely filled with water and generate no steam (correct)

What is the term for pressure gauges that are calibrated in terms of height of water?

Altitude gauge Signup and view all the answers

How many pointers does an altitude gauge have?

Two Signup and view all the answers

What is the purpose of the second pointer on an altitude gauge?

To show the normal height of water in the system Signup and view all the answers

What should the pressure be in a closed hot water heating system?

Greater than the altitude Signup and view all the answers

What is the requirement for the scale on the dial of the pressure or altitude gauge?

It must be graduated to between 1 ½ and 3 ½ times the safety relief valve set pressure Signup and view all the answers

What is the maximum water temperature limit for open expansion tanks?

80°C Signup and view all the answers

Where are closed expansion tanks often located?

In the boiler room Signup and view all the answers

What happens to the air cushion inside the expansion tank when the water expands?

It gets compressed Signup and view all the answers

What is the purpose of the air separator in Figure 9?

To separate air bubbles from the water flow Signup and view all the answers

What is the minimum hydrostatic test pressure required for expansion tanks in systems designed for a working pressure of 200 kPa or less?

520 kPa Signup and view all the answers

What type of expansion tanks must be designed and constructed in accordance with ASME BPVC VIII, Division 1?

Closed expansion tanks for systems above 200 kPa Signup and view all the answers

What is the advantage of installing isolation and drain valves in the piping to a bladder-style expansion tank?

To permit servicing, replacing, and repairing the expansion tank without draining the system Signup and view all the answers

What problem do non-bladder style expansion tanks pose?

Corrosion of steel piping and heating units Signup and view all the answers

What is the purpose of the liquid in pressure gauges found before and after hot water circulation pumps?

To dampen the needle movement in the gauge Signup and view all the answers

What is the minimum temperature reading required for thermometers in hot water heating boilers?

20°C Signup and view all the answers

What is the term for a gauge that combines pressure and temperature measurement, and also includes an altitude scale?

Tridicator gauge Signup and view all the answers

How many safety relief valves are required for each hot water heating boiler?

At least one Signup and view all the answers

What is the maximum permissible increase in pressure above the MAWP when a single safety relief valve is used?

10% above MAWP Signup and view all the answers

What is the purpose of stop valves in the supply and return pipe connections of hot water heating boilers?

To allow the boiler to be drained without emptying the system Signup and view all the answers

What is the minimum temperature rating required for stop valves in hot water heating boilers?

120°C Signup and view all the answers

What is the purpose of the drain valve in hot water heating boilers?

To drain the boiler for maintenance or extended layup Signup and view all the answers

What happens to the excess water in the heating system when it expands?

It flows into the expansion tank Signup and view all the answers

What happens to the water in the expansion tank when the system cools down and decreases in volume?

It flows back into the system Signup and view all the answers

MEDIUM What is the purpose of low water fuel cut-offs in hot water heating boilers?

To shut off the fuel supply when the boiler water level falls below a certain point Signup and view all the answers

What is the significance of the cock on the pipe near the pressure or altitude gauge?

It allows the gauge to be shut off from the boiler for maintenance Signup and view all the answers

Why are siphons not required between the gauge and the boiler in hot water service?

Because hot water boilers are completely filled with water Signup and view all the answers

What is the term for pressure gauges that are calibrated in terms of height of water?

Altitude gauge Signup and view all the answers

How many pointers does a typical altitude gauge have?

Two pointers, one that is operated by the bourdon tube assembly and another that is manually placed in a fixed position Signup and view all the answers

What should the pressure be in a closed hot water heating system?

Greater than the altitude Signup and view all the answers

What is the requirement for the scale on the dial of the pressure or altitude gauge?

It must be graduated to between 1 ½ and 3 ½ times the safety relief valve set pressure Signup and view all the answers

What is the purpose of expansion tanks in hot water heating systems?

To absorb the expansion of water when it heats up Signup and view all the answers

What is the minimum temperature reading required for thermometers in hot water heating boilers?

20°C Signup and view all the answers

What is the purpose of the safety relief valve in hot water heating boilers?

To relieve pressure in the boiler Signup and view all the answers

What is the minimum pressure rating required for stop valves in hot water heating boilers?

Equal to the pressure stamped on the boiler Signup and view all the answers

Why are stop valves not required in certain down feed hot water systems?

Because the boiler is located above the system Signup and view all the answers

What is the purpose of the expansion tank in a hot water heating system?

To provide storage space for excess water due to expansion Signup and view all the answers

What happens to the water in the expansion tank when the system cools down and decreases in volume?

It flows back into the system Signup and view all the answers

What is the maximum permissible increase in pressure above the MAWP when a single safety relief valve is used?

10% above the MAWP Signup and view all the answers

What is the purpose of the drain valve in hot water heating boilers?

To drain the boiler for maintenance or extended layup Signup and view all the answers

What is the requirement for the size of safety relief valves in hot water heating boilers?

Between DN 20 and DN 100 (NPS ¾ and NPS 4) Signup and view all the answers

What is the term for a gauge that combines pressure and temperature measurement, and also includes an altitude scale?

Tridicator gauge Signup and view all the answers

What is the primary purpose of an expansion tank in a hot water heating system?

To provide a cushion for thermal expansion of the water Signup and view all the answers

What is the requirement for the hydrostatic test pressure of an expansion tank in a system designed for a working pressure of 200 kPa or less?

520 kPa Signup and view all the answers

What is the advantage of using a bladder-style expansion tank in a hot water heating system?

It eliminates the problem of oxygen corrosion Signup and view all the answers

What is the purpose of the gauge glass in the expansion tank shown in Figure 9?

To measure the water level in the tank Signup and view all the answers

What is the limitation of open expansion tanks?

They can only be used in systems with a maximum water temperature of 80°C Signup and view all the answers

What is the purpose of the shutoff valve in the connecting line between the expansion tank and the hot water supply header?

To allow the tank to be drained without draining the system Signup and view all the answers

What is the requirement for expansion tanks in systems designed to operate above 200 kPa?

They must be designed and constructed in accordance with ASME BPVC VIII, Division 1 Signup and view all the answers

What is the consequence of using non-bladder style expansion tanks in a hot water heating system?

It causes corrosion of steel piping and heating units Signup and view all the answers

HARD What is the primary purpose of including a pressure or altitude gauge in a hot water heating boiler?

To indicate whether the hot water system is full Signup and view all the answers

Why is a siphon not required between the gauge and the boiler in hot water service?

Because hot water boilers are completely filled with water Signup and view all the answers

What determines the calibration of a pressure or altitude gauge?

The safety relief valve set pressure Signup and view all the answers

What is the purpose of the cock on the pipe near the pressure or altitude gauge?

To shut off the gauge from the boiler Signup and view all the answers

What is the significance of the term 'altitude' gauge?

It refers to pressure gauges calibrated in terms of height of water Signup and view all the answers

What is the purpose of the second pointer on an altitude gauge?

To show the normal height of water in the system Signup and view all the answers

What is the requirement for the scale on the dial of the pressure or altitude gauge?

It must be graduated to between 1 ½ and 3 ½ times the safety relief valve set pressure Signup and view all the answers

What is the primary purpose of the expansion tank in a hot water heating system?

To accommodate the expansion of water as it heats up Signup and view all the answers

What is the maximum pressure that a additional safety relief valve can be set to, for boilers exceeding 400 kPa?

The MAWP plus 5% Signup and view all the answers

What is the minimum pressure rating required for stop valves in hot water heating boilers?

At least equal to the pressure stamped on the boiler Signup and view all the answers

What is the purpose of the expansion tank in a hot water heating system?

To provide storage space for excess water due to expansion Signup and view all the answers

What is the minimum temperature reading required for thermometers in hot water heating boilers?

At least 20°C Signup and view all the answers

What is the requirement for the size of safety relief valves in hot water heating boilers?

Between DN 20 and DN 100 Signup and view all the answers

When are stop valves not required in down feed hot water systems?

When the boiler is located above the system Signup and view all the answers

What is the term for a gauge that combines pressure and temperature measurement, and also includes an altitude scale?

Tridicator gauge Signup and view all the answers

What happens to the excess water in the heating system when it expands?

It flows into the expansion tank Signup and view all the answers

What is the maximum permissible increase in pressure above the MAWP when a single safety relief valve is used?

10% above the MAWP Signup and view all the answers

What is the purpose of the drain valve in hot water heating boilers?

To drain the boiler for maintenance or extended layup Signup and view all the answers

What is the primary purpose of ASME BPVC IV Part HG-709.2?

To calculate the required volume of the expansion tank Signup and view all the answers

What is the significance of the air separator in Figure 9?

It separates air bubbles from the water flow and directs them into the tank Signup and view all the answers

What is the consequence of using non-bladder style expansion tanks?

They cause corrosion of steel piping and heating units Signup and view all the answers

What is the purpose of a shutoff valve in the connecting line between the expansion tank and the hot water supply header?

To allow the tank to be drained without draining the system Signup and view all the answers

What is the requirement for the design of expansion tanks in systems designed to operate above 200 kPa?

They must be designed in accordance with ASME BPVC VIII, Division 1 Signup and view all the answers

What is the advantage of using bladder-style expansion tanks?

They eliminate the problem of oxygen dissolving into the water Signup and view all the answers

What is the purpose of the gauge glass in the expansion tank shown in Figure 9?

To show the level of the water in the tank Signup and view all the answers

What is the limitation of open expansion tanks?

They can only be used in systems with a maximum water temperature of 80°C Signup and view all the answers

Match the following components with their functions:

Pressure or altitude gauge = Measures pressure in hot water heating boilers Thermometer = Measures temperature in hot water heating boilers Safety relief valve = Opens at a set pressure to release excess pressure Expansion tanks = Stores excess water in hot water heating systems Signup and view all the answers

Match the following types of valves with their uses:

Stop valves = Isolates sections of piping for maintenance Low water fuel cut-offs = Cuts off fuel supply if water level is too low Safety relief valve = Opens at a set pressure to release excess pressure Drain valve = Drains water from hot water heating boilers Signup and view all the answers

Match the following components with their locations:

Expansion tanks = Located near the boiler or in the piping system Stop valves = In the supply and return pipe connections Pressure or altitude gauge = Connected to the boiler or flow connection Thermometer = On the boiler or in the piping system Signup and view all the answers

Match the following components with their benefits:

Bladder-style expansion tanks = Reduces water hammer and noise Isolation and drain valves = Easier maintenance and draining of expansion tanks Siphons = Not required in hot water heating systems ASME BPVC IV = Establishes safety standards for boilers and pressure vessels Signup and view all the answers

Match the following components with their characteristics:

Altitude gauge = Calibrated in terms of height of water Pressure gauge = Measures pressure in hot water heating boilers Thermometer = Measures temperature in hot water heating boilers Safety relief valve = Opens at a set pressure to release excess pressure Signup and view all the answers

Match the following components with their purposes:

Expansion tanks = Store excess water in hot water heating systems Pressure or altitude gauge = Monitor pressure in hot water heating boilers Thermometer = Monitor temperature in hot water heating boilers Safety relief valve = Releases excess pressure in hot water heating boilers Signup and view all the answers

Match the following components with their requirements:

Pressure or altitude gauge = Scale graduated to 1 ½ to 3 ½ times the safety relief valve set pressure Thermometer = Minimum temperature reading required Stop valves = Minimum pressure rating required Expansion tanks = Designed and constructed according to ASME BPVC VIII, Division 1 Signup and view all the answers

Match the following components with their limitations:

Open expansion tanks = Limited by maximum water temperature Closed expansion tanks = May be located indoors or outdoors Bladder-style expansion tanks = None mentioned Non-bladder style expansion tanks = Pose the problem of waterlogging Signup and view all the answers

Match the following components with their functions in a hot water heating system:

Air separator = Separates air bubbles from the water flow Drain valve = Allows draining the expansion tank without emptying the system Gauge glass = Monitors the level of water in the expansion tank Shutoff valve = Isolates the expansion tank for maintenance and repair Signup and view all the answers

Match the following types of expansion tanks with their characteristics:

Open expansion tank = Limited to systems with a maximum water temperature of 80°C Closed expansion tank = Can be used in systems with high operating temperatures and pressures Bladder-style expansion tank = Eliminates the problem of oxygen dissolving into the water Non-bladder style expansion tank = Brings air into direct contact with the water Signup and view all the answers

Match the following codes and standards with their applications:

ASME BPVC IV Part HG-709 = Covers provisions for thermal expansion in hot water systems ASME BPVC VIII, Division 1 = Applies to expansion tanks for systems designed to operate above 200 kPa ASME BPVC IV Part HG-709.2 = Addresses expansion tanks and includes calculations for determining the required volume ASME BPVC = Applies to hot water heating boilers and systems Signup and view all the answers

Match the following components with their locations in a hot water heating system:

Expansion tank = Often located in the boiler room Air separator = Connected to the supply main Shutoff valve = In the connecting line between the expansion tank and the hot water supply header Gauge glass = In the expansion tank Signup and view all the answers

Match the following conditions with their effects on the expansion tank:

System cools down and decreases in volume = Water in the expansion tank contracts System increases in temperature and pressure = Water in the expansion tank expands Drain valve is opened = Water in the expansion tank is drained Hydrostatic test is performed = Expansion tank is pressurized to 520 kPa Signup and view all the answers

Match the following components with their purposes in preventing corrosion:

Bladder-style expansion tank = Eliminates oxygen dissolving into the water Nitrogen-charged expansion tank = Prevents corrosion of steel piping and heating units Air separator = Separates air bubbles from the water flow Drain valve = Drains the expansion tank without emptying the system Signup and view all the answers

Match the following components with their requirements:

Expansion tank = Must be designed for a minimum hydrostatic test pressure of 520 kPa Stop valve = Must have a minimum pressure rating of 200 kPa Safety relief valve = Must be sized according to the system's requirements Thermometer = Must have a minimum temperature rating of 80°C Signup and view all the answers

Match the following components with their advantages:

Bladder-style expansion tank = Eliminates the problem of oxygen dissolving into the water Closed expansion tank = Can be used in systems with high operating temperatures and pressures Isolation and drain valves = Allow servicing, replacing, and repairing the expansion tank without draining the system Gauge glass = Monitors the level of water in the expansion tank Signup and view all the answers

Match the following components of hot water heating boilers with their respective functions:

Pressure gauge = Measures pressure in the boiler Thermometer = Measures temperature in the boiler Safety relief valve = Releases excess pressure in the boiler Drain valve = Allows draining of the boiler for maintenance Signup and view all the answers

Match the following types of valves with their respective requirements:

Stop valve = Minimum pressure rating equal to the pressure stamped on the boiler Drain valve = Minimum temperature rating of 120°C Safety relief valve = Size between DN 20 and DN 100 Expansion tank valve = Must be designed and constructed in accordance with ASME BPVC VIII, Division 1 Signup and view all the answers

Match the following components of hot water heating boilers with their respective locations:

Pressure gauge = Before and after hot water circulation pumps Thermometer = At or near the boiler outlet Stop valve = In the supply and return pipe connections of each boiler Drain valve = At the bottom connection of the boiler Signup and view all the answers

Match the following components of hot water heating boilers with their respective purposes:

Expansion tank = Provides storage space for excess water due to expansion Safety relief valve = Prevents excessive pressure buildup Stop valve = Allows the boiler to be drained without emptying the entire piping system Drain valve = Allows draining of the boiler for maintenance Signup and view all the answers

Match the following components of hot water heating boilers with their respective requirements:

Thermometer = Minimum reading of 20°C and maximum reading of 160°C Safety relief valve = Set to relieve at or below the maximum allowable working pressure of the boiler Stop valve = Must be fully open during operation Drain valve = Must be located at the lowest point of the boiler Signup and view all the answers

Match the following components of hot water heating boilers with their respective types:

Expansion tank = Open or closed type Stop valve = Gate valve, ball valve, or butterfly valve Safety relief valve = Automatic reseating type Drain valve = Full port opening valve Signup and view all the answers

Match the following components of hot water heating boilers with their respective effects:

Expansion tank = Prevents excessive pressure buildup Safety relief valve = Allows excess water to flow into the expansion tank Stop valve = Prevents the boiler from being drained without emptying the entire piping system Drain valve = Causes the pressure to rise more than 10% above the MAWP Signup and view all the answers

Match the following components of hot water heating boilers with their respective relationships:

Safety relief valve = Must be set to relieve at or below the maximum allowable working pressure of the boiler Expansion tank = Must be connected to the boiler and the system Stop valve = Must be located in the supply and return pipe connections of each boiler Drain valve = Must be located at the bottom connection of the boiler Signup and view all the answers

Match the following components of hot water heating boilers with their respective limitations:

Open expansion tank = Maximum water temperature limit Safety relief valve = Maximum permissible increase in pressure above the MAWP Stop valve = Minimum pressure rating Drain valve = Must be fully open during operation Signup and view all the answers

Match the following components of hot water heating boilers with their respective advantages:

Bladder-style expansion tank = Allows for easier installation and maintenance Safety relief valve = Prevents excessive pressure buildup Stop valve = Allows the boiler to be drained without emptying the entire piping system Drain valve = Allows draining of the boiler for maintenance Signup and view all the answers

Study Notes

Fittings Required by ASME BPVC IV for Hot Water Heating Boilers

Pressure or altitude gauge
Thermometer
Safety relief valve
Temperature controls
Low water fuel cut-offs
Stop valves
Blowoff or drain connections
Expansion tanks

Pressure or Altitude Gauges

Each hot water heating boiler must have a pressure or altitude gauge connected to it
The gauge must not be shut off from the boiler except by a cock with tee or lever handle
The handle of the cock must be parallel to the pipe in which it is located when the cock is open
Altitude gauges indicate whether the hot water system is full
Pressure gauges are also found before and after hot water circulation pumps

Thermometer

ASME BPVC IV requires all hot water heating boilers to have an easily read thermometer or temperature sensor (with display)
The thermometer or sensor must indicate the hot water temperature at or near the boiler outlet
The thermometer must have a minimum reading of at least 20°C, and a maximum reading of at least 160°C, but not more than 205°C

Safety Relief Valves

Each hot water heating boiler must have at least one automatic reseating type safety relief valve, set to relieve at or below the maximum allowable working pressure of the boiler
Safety relief valves must be between DN 20 and DN 100 (NPS ¾ and NPS 4) in size
When a single safety relief valve is used, it must have sufficient relief capacity so that, with the fuel burning equipment operated at maximum capacity, the pressure cannot rise more than 10% above the MAWP

Stop Valves

Stop valves must be placed in the supply and return pipe connections on all hot water heating boilers
The minimum pressure rating of all valves must be at least equal to the pressure stamped on the boiler
The temperature rating must not be less than 120°C

Drain Valves

Each hot water heating boiler must have a bottom connection fitted with a drain valve
This permits draining of the boiler for maintenance or extended layup

Expansion Tanks

The purpose of the expansion tank is to provide storage space for excess water (due to expansion) in the heating system
Expansion tanks must be installed that will be consistent with the volume and capacity of the system
Expansion tanks are connected to the supply main, or directly to the top of the boiler
Closed expansion tanks can be used in systems with high operating temperatures and pressures

Open and Closed Expansion Tanks

Open expansion tanks are rarely used today and were limited to systems with a maximum water temperature of 80°C
Closed expansion tanks can be used in systems with high operating temperatures and pressures

Fittings Required by ASME BPVC IV for Hot Water Heating Boilers

Pressure or altitude gauge
Thermometer
Safety relief valve
Temperature controls
Low water fuel cut-offs
Stop valves
Blowoff or drain connections
Expansion tanks

Pressure or Altitude Gauges

Each hot water heating boiler must have a pressure or altitude gauge connected to it
The gauge must not be shut off from the boiler except by a cock with tee or lever handle
The handle of the cock must be parallel to the pipe in which it is located when the cock is open
Altitude gauges indicate whether the hot water system is full
Pressure gauges are also found before and after hot water circulation pumps

Thermometer

ASME BPVC IV requires all hot water heating boilers to have an easily read thermometer or temperature sensor (with display)
The thermometer or sensor must indicate the hot water temperature at or near the boiler outlet
The thermometer must have a minimum reading of at least 20°C, and a maximum reading of at least 160°C, but not more than 205°C

Safety Relief Valves

Each hot water heating boiler must have at least one automatic reseating type safety relief valve, set to relieve at or below the maximum allowable working pressure of the boiler
Safety relief valves must be between DN 20 and DN 100 (NPS ¾ and NPS 4) in size
When a single safety relief valve is used, it must have sufficient relief capacity so that, with the fuel burning equipment operated at maximum capacity, the pressure cannot rise more than 10% above the MAWP

Stop Valves

Stop valves must be placed in the supply and return pipe connections on all hot water heating boilers
The minimum pressure rating of all valves must be at least equal to the pressure stamped on the boiler
The temperature rating must not be less than 120°C

Drain Valves

Each hot water heating boiler must have a bottom connection fitted with a drain valve
This permits draining of the boiler for maintenance or extended layup

Expansion Tanks

The purpose of the expansion tank is to provide storage space for excess water (due to expansion) in the heating system
Expansion tanks must be installed that will be consistent with the volume and capacity of the system
Expansion tanks are connected to the supply main, or directly to the top of the boiler
Closed expansion tanks can be used in systems with high operating temperatures and pressures

Open and Closed Expansion Tanks

Open expansion tanks are rarely used today and were limited to systems with a maximum water temperature of 80°C
Closed expansion tanks can be used in systems with high operating temperatures and pressures

Fittings Required by ASME BPVC IV for Hot Water Heating Boilers

Pressure or altitude gauge
Thermometer
Safety relief valve
Temperature controls
Low water fuel cut-offs
Stop valves
Blowoff or drain connections
Expansion tanks

Pressure or Altitude Gauges

Each hot water heating boiler must have a pressure or altitude gauge connected to it
The gauge must not be shut off from the boiler except by a cock with tee or lever handle
The handle of the cock must be parallel to the pipe in which it is located when the cock is open
Altitude gauges indicate whether the hot water system is full
Pressure gauges are also found before and after hot water circulation pumps

Thermometer

ASME BPVC IV requires all hot water heating boilers to have an easily read thermometer or temperature sensor (with display)
The thermometer or sensor must indicate the hot water temperature at or near the boiler outlet
The thermometer must have a minimum reading of at least 20°C, and a maximum reading of at least 160°C, but not more than 205°C

Safety Relief Valves

Each hot water heating boiler must have at least one automatic reseating type safety relief valve, set to relieve at or below the maximum allowable working pressure of the boiler
Safety relief valves must be between DN 20 and DN 100 (NPS ¾ and NPS 4) in size
When a single safety relief valve is used, it must have sufficient relief capacity so that, with the fuel burning equipment operated at maximum capacity, the pressure cannot rise more than 10% above the MAWP

Stop Valves

Stop valves must be placed in the supply and return pipe connections on all hot water heating boilers
The minimum pressure rating of all valves must be at least equal to the pressure stamped on the boiler
The temperature rating must not be less than 120°C

Drain Valves

Each hot water heating boiler must have a bottom connection fitted with a drain valve
This permits draining of the boiler for maintenance or extended layup

Expansion Tanks

The purpose of the expansion tank is to provide storage space for excess water (due to expansion) in the heating system
Expansion tanks must be installed that will be consistent with the volume and capacity of the system
Expansion tanks are connected to the supply main, or directly to the top of the boiler
Closed expansion tanks can be used in systems with high operating temperatures and pressures

Open and Closed Expansion Tanks

Open expansion tanks are rarely used today and were limited to systems with a maximum water temperature of 80°C
Closed expansion tanks can be used in systems with high operating temperatures and pressures

Fittings Required by ASME BPVC IV for Hot Water Heating Boilers

Pressure or altitude gauge
Thermometer
Safety relief valve
Temperature controls
Low water fuel cut-offs
Stop valves
Blowoff or drain connections
Expansion tanks

Pressure or Altitude Gauges

Each hot water heating boiler must have a pressure or altitude gauge connected to it
The gauge must not be shut off from the boiler except by a cock with tee or lever handle
The handle of the cock must be parallel to the pipe in which it is located when the cock is open
Altitude gauges indicate whether the hot water system is full
Pressure gauges are also found before and after hot water circulation pumps

Thermometer

ASME BPVC IV requires all hot water heating boilers to have an easily read thermometer or temperature sensor (with display)
The thermometer or sensor must indicate the hot water temperature at or near the boiler outlet
The thermometer must have a minimum reading of at least 20°C, and a maximum reading of at least 160°C, but not more than 205°C

Safety Relief Valves

Each hot water heating boiler must have at least one automatic reseating type safety relief valve, set to relieve at or below the maximum allowable working pressure of the boiler
Safety relief valves must be between DN 20 and DN 100 (NPS ¾ and NPS 4) in size
When a single safety relief valve is used, it must have sufficient relief capacity so that, with the fuel burning equipment operated at maximum capacity, the pressure cannot rise more than 10% above the MAWP

Stop Valves

Stop valves must be placed in the supply and return pipe connections on all hot water heating boilers
The minimum pressure rating of all valves must be at least equal to the pressure stamped on the boiler
The temperature rating must not be less than 120°C

Drain Valves

Each hot water heating boiler must have a bottom connection fitted with a drain valve
This permits draining of the boiler for maintenance or extended layup

Expansion Tanks

The purpose of the expansion tank is to provide storage space for excess water (due to expansion) in the heating system
Expansion tanks must be installed that will be consistent with the volume and capacity of the system
Expansion tanks are connected to the supply main, or directly to the top of the boiler
Closed expansion tanks can be used in systems with high operating temperatures and pressures

Open and Closed Expansion Tanks

Open expansion tanks are rarely used today and were limited to systems with a maximum water temperature of 80°C
Closed expansion tanks can be used in systems with high operating temperatures and pressures

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Description

This quiz covers the required fittings for hot water heating boilers according to ASME BPVC IV, including pressure or altitude gauges, thermometers, and more.