87%-Efficiency Boilers – Special Instructions

NOTE: The constructions of the 84%- (standard) and 87%-efficiency (optional) boilers are very similar, and they are installed to the same requirements, except as noted in this section.

Water Piping

An 87%-efficiency boiler requires a minimum inlet water temperature of 120ºF (49ºC) to prevent exces- sive condensation in the combustion chamber. An 87%-efficiency boiler operated with an inlet tempera- ture of less than 120ºF (49ºC) must have a manual bypass or an approved low-temperature operation system to prevent problems with condensation. A man- ual bypass, shown in Fig. 15, must be piped into the system at the time of installation. This piping is like a primary/secondary boiler installation with a bypass in the secondary boiler piping. Raypak strongly recomm-

ends that a thermometer be placed into the boiler inlet piping next to the in/out header to facilitate tempera- ture adjustment. Inlet water temperatures below 120ºF (49ºC) can excessively cool the products of combus- tion, resulting in condensation on the heat exchanger.

Venting

CAUTION: Proper installation of flue venting is criti- cal for the safe and efficient operation of the boiler.

Appliance Categories

See Table T for appliance category requirements for the 87%-efficiency Hi Delta.

NOTE: For additional information on appliance categorization, see appropriate code NFGC (U.S.) and B149 (Canada), or applicable local building codes.

Model

10°F

T

20°F

T

30°F

T

Min. Flow

 

Max Flow

 

No.

gpm

 

P (ft)

gpm

 

P (ft)

gpm

 

P (ft)

gpm

P (ft)

T

gpm

P (ft)

T

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

302BE

52

 

3.3

26

 

<1.0

N/A

 

N/A

20

<1.0

26

90

9.8

6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

402BE

69

 

5.8

35

 

1.5

23

 

<1.0

20

<1.0

35

90

10.0

8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

502BE

87

 

9.1

44

 

2.5

29

 

1.1

22

<1.0

40

90

10.4

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

652BE

N/A

 

N/A

57

 

4.4

38

 

2.0

28

1.1

40

90

10.8

13

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

752BE

N/A

 

N/A

65

 

6.1

44

 

2.8

33

1.6

40

90

11.3

15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

902BE

N/A

 

N/A

78

 

8.9

52

 

4.1

39

2.3

40

90

11.7

17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Note: Basis for minimum flow is 20 gpm or 40°F ∆T. Basis for maximum flow is 90 gpm.

Table S: Heater Rate of Flow and Pressure Drop

Combustion

Exhaust

Heater Venting

Certified

Combustion Air

Air Supply

Configuration

Category

Materials

 

Inlet Material

 

Vertical Natural Draft

II

Stainless Steel

 

 

From Inside Building

Venting

(Gas Tight)

 

 

 

 

 

(Non-Direct Venting)

Horizontal Through-

IV

AL29-4C

 

 

 

the-Wall Venting

 

 

 

 

 

 

 

 

Vertical Natural Draft

II

Stainless Steel

Galvanized Steel

From Outside Building

Venting

(Gas Tight)

 

PVC

 

 

(Direct Venting)

Horizontal Through-

IV

AL29-4C

 

ABS

 

the-Wall Venting

 

CPVC

 

 

 

 

Table T: Category Determination for Venting Purpose and Venting Arrangement

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Raypak 902B, 302B manual 87%-Efficiency Boilers Special Instructions, Water Piping, Venting Appliance Categories
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302B, 902B specifications

Raypak is a prominent name in the heating industry, particularly known for its advanced technology and robust design in residential and commercial heating solutions. Two of their notable models, the Raypak 302B and 402B, exemplify innovation and efficiency in hydronic heating systems, designed to meet diverse needs while ensuring optimal performance.

The Raypak 302B and 402B are high-efficiency boilers that utilize gas-fueled systems. The 302B model has a heating capacity of 302,000 BTU/h, while the 402B boasts a maximum capacity of 402,000 BTU/h. This range of heating output makes these models suitable for a variety of applications, from residential heating needs to larger commercial spaces that require a reliable heat source.

One of the standout features of the Raypak 302B and 402B is their use of fire-tube heat exchanger technology. This design promotes efficient heat transfer and allows for lower emissions, thus minimizing the environmental impact. The fire-tube design also contributes to a longer lifespan and reduced maintenance costs, making these boilers a cost-effective solution over time.

Equipped with advanced control systems, the Raypak 302B and 402B ensure precise temperature regulation and improved energy usage. The digital display provides real-time feedback and diagnostics, enhancing user experience and simplifying troubleshooting. These models are also compatible with various building management systems, providing users with versatility in integration to optimize building performance.

In addition to their technological advancements, these boilers are designed with user safety and convenience in mind. They include features such as built-in safety controls, easy access for service and maintenance, and a compact footprint to fit into tight spaces. Their robust construction ensures durability, which is crucial for systems that operate under high demand.

Moreover, both models have been engineered to succeed in various climates, making them reliable choices for users in diverse geographical locations. With their energy-efficient operation, reliable performance, and advanced features, the Raypak 302B and 402B embody quality and innovation in the heating market, ensuring comfortable environments while lowering energy costs and environmental footprints.
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