8 Finishing

A. Hearth Extension

A hearth extension must be installed with all fireplaces to protect the combustible floor in front of the fireplace from both radiant heat and sparks. See Figures 8.1-8.3.

 

High temperature

 

 

 

 

(300°F min.) continuous,

 

 

HX3 or HX4

non-combustible sealant

Fireplace

 

non-combustible material

Protective

insulation

Hearth Ext

Tile, stone or other

 

 

or equivilent

 

 

 

 

 

 

(see Table below)

 

 

 

Metal Hearth

 

 

 

 

Strip

 

 

2 in. (51 mm)

 

 

Floor constructed of wood or

required

 

 

other combustible material

 

 

 

Figure 8.1 Hearth Extension Construction

WARNING

Fire Risk

•Metal hearth strips MUST be installed. Sparks or embers may ignite flooring.

This fireplace has been tested and approved for use with a hearth extension insulated to a minimum R value of 1.16.

To substitute materials for the factory-available hearth ex- tensions, see Figure 8.3 and calculate insulation alterna- tives as per Table 8.1 and the following formulas:

1 in. (25 mm) overlap

Metal strips are placed 2 in. (51 mm) under the front of the fireplace and must extend beyond the front and sides of fireplace opening by 2 in. (51 mm).

Figure 8.2 Positioning the Protective Metal Hearth Strips

WARNING

Fire Risk

•Hearth extensions must be installed exactly as specified.

High temperatures or hot embers may ignite concealed combustibles.

•Thermal conductivity per inch thickness = k

•k = (BTU)(inch) / (foot2)(hour)(°F)

•Required thickness = Rk

•Thermal resistance per inch thickness = r

•r = (foot2)(hour)(°F) / (BTU)(inch)

•Required thickness = R / rB.

Table 8.1

Hearth Extension Insulation Alternatives, R Value = 1.16

 

k per inch

r per inch

Minimum thickness

Material

thick

thick

required

Hearth & Home HX3, HX4

0.43

2.33

1/2 in.

USG Micore 300™

0.46

2.18

1/2 in.

USG Durock™ Cement Board

1.92

0.52

2-1/4 in.

 

 

 

 

Cement Mortor

5.0

0.20

5-7/8 in.

Common Brick

5.0

0.20

5-7/8 in.

 

 

 

 

Ceramic Tile

12.50

0.08

14-5/8 in.

Armstrong Privacy Plus

 

 

 

 

 

 

 

Marble

14.3-20.0

0.07-0.05

16-5/8 in. - 23-3/8 in.

 

A

 

C

B

 

 

 

 

 

 

 

 

 

 

 

 

Hearth Extension Dimensions

 

Model #

A

 

B

 

C

RHW-415

in.

52

 

16

 

8

mm

1321

 

406

 

203

 

 

 

 

 

 

 

 

 

 

RHW-485

in.

66

 

20

 

8

mm

1676

 

508

 

203

 

 

 

Figure 8.3 Hearth Extension Dimensions

Heat & Glo • RHW-485 • 33221 Rev O • 08/06

25

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Hearth and Home Technologies RHW-485H owner manual Finishing, Hearth Extension
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RHW-485, RHW-485H specifications

Hearth and Home Technologies (HHT) is a leader in the manufacture of innovative and high-quality hearth products, and their RHW-485H and RHW-485 models are no exceptions. These wood-burning heaters are designed to provide efficient and effective heating solutions for residential spaces while offering an elegant aesthetic that complements various home decors.

One of the main features of the RHW-485H and RHW-485 is their impressive heating capacity. Both models are designed to heat areas up to 2,000 square feet efficiently, making them ideal for large living spaces or open-concept homes. This significant heating capability is made possible by advanced combustion technology that allows for a longer burn time, ensuring extended warmth throughout the night.

Another defining characteristic of these units is their clean-burning technology. HHT has incorporated a unique air wash system that enhances combustion efficiency and minimizes emissions. This ensures that homeowners can enjoy the beauty and comfort of a wood fire while adhering to environmental standards. Furthermore, these models have received certification from the EPA for meeting stringent guidelines, making them an excellent choice for those who are environmentally conscious.

In terms of design, the RHW-485H features an attractive cast iron door with a large viewing window. This allows for an unobstructed view of the mesmerizing flames and adds a touch of sophistication to any room. The RHW-485, while similar in heating efficiency, offers slightly different aesthetic options, giving homeowners the ability to choose a model that aligns with their personal style.

Both models come equipped with a robust refractory system that enhances heat retention and distribution. This technology ensures that heat is released evenly and efficiently, providing consistent warmth without the need for constant refueling. Additionally, they feature adjustable air controls that allow users to manage burn rates and heat output according to their preferences.

Another important aspect is the ease of installation and maintenance. The RHW-485H and RHW-485 have been designed with user-friendly features, including accessible clean-out ports that simplify ash removal. This reduces the hassle of routine care, allowing homeowners to enjoy their fireplace without extensive upkeep.

In conclusion, Hearth and Home Technologies’ RHW-485H and RHW-485 models are premium wood-burning heaters that combine efficiency, elegance, and environmental responsibility. They offer a perfect blend of modern technology and classic design, making them an excellent choice for discerning homeowners looking to enhance their living space with warmth and style.
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