Vermont Casting 2477 - Manual (Page 10)

10
Dutchwest Non-Catalytic Convection Heater
30002314
Procedure:
1. Convert specifications to R-value:
i. R-value given - no conversion needed.
ii. k-factor is given with a required thickness (T) in
inches:
iii. K-factor is given with a required thickness (T) in
inches:
iv. r-factor is given with a required thickness (T) in
inches: R = r x T
2. Determine the R-value of the proposed alternate
floor protector:
i. Use the formula in Step 1 to convert values not
expressed as R.
ii. For multiple layers, add R-values of each layer to
determine overall R-value.
3. If the overall R-value of the system is greater than
the R-value of the specified floor protector, the alter-
nate is acceptable.
EXAMPLE: The specified floor protector should be 7/8-
inch thick material with k-factor of 0.84. The proposed
alternate is 4” brick with an r-factor of 0.2 over 1/8”
mineral board with a k-factor of 0.29
Step a: Use formula above to convert specification to
R-value:
Step b: Calculate R of proposed system.
4” brick of r = 0.2, therefore:
R
brick
= 0.2 x 4 = 0.8
1/8” mineral board of k = 0.29, therefore
R
mineralboard
= x 0.125 = 0.431
R
total
= R
brick
+ R
mineralboard
= 0.8 + 0.431 = 1.231
Step c: Compare proposed system Rtotal of 1.231 to
specified R of 1.04. Since proposed system Rtotal is
greater than required, the system is acceptable.
Definitions
To install the heater without legs as a fireplace insert,
the floor must be completely noncombustible, such as
an unpainted concrete floor over earth.
Many fireplaces do not satisfy the “completely non-
combustible” requirement because the brick or con-
crete hearth in front of the fireplace opening usually is
supported by heavy wooden framing as in Figure 13.
Because heat passes readily through brick or concrete,
it can easily pass through to the wood. As a result, such
fireplace hearths are considered a combustible floor.
You may not install a heater on a combustible hearth
without legs. Standard leg installations must include the
bottom heat shield. The floor protector must also meet
standard requirements for freestanding installations.
Floor Protection for Fireplace
Installations with Standard Legs
Fireplace installations with the standard legs and the
bottom heat shield must have a floor protector of the
same construction as that specified for freestanding
installations: an approved 7/8” (22mm) noncombustible
hearth pad with K = 0.84 BTU/in ft
2 hr. °F or equivalent
material with an R-value of at least 1.04 (Refer to “How
to Determine if Alternate Floor Protection Materials are
Acceptable” section) The floor protector must extend at
least 16” (406 mm) [18” / 457 mm in Canada] from the
front of the stove and from the left (loading door) side,
and at least 6” (152 mm) [8” (203 mm) in Canada] from
the right side and rear. It must also provide protection
beneath any horizontal runs of the chimney connector,
including 2” to either side.
Many raised hearths will extend less than the required
distance from the front of the heater when it is installed.
In such cases, sufficient floor protection, as described
above, must be added to extend the hearth 16” (406
mm) [18” (457 mm) in Canada].
Hearth rugs do not satisfy the requirements for floor
protection.
Fireplace insert installations also have specific clear-
ance requirements to the side walls, side decorative
trim, and fireplace mantel. This information is found in
“Fireplace Installation Clearances” in this section.
REMINDER- FIREPLACE INSERT INSTALLATIONS
WITHOUT LEGS ARE PERMISSIBLE ONLY IF THE
HEARTH IS COMPLETELY NONCOMBUSTIBLE,
SUCH AS UNPAINTED CONCRETE OVER EARTH.
Fireplace Installations
The Dutchwest Model 2477 has a reversible flue collar
to allow for either top exit or rear exit installations.
You may install your Dutchwest Model 2477 in an exist-
ing fireplace as a fireplace insert with no legs, or with
the standard legs attached.
R = x T
1
K x 12
R = x T
1
k
R = x T = x 0.875 = 1.04
1
k
1
0.84
1
0.29
R = (ft
2 )(hr)(°F)
Btu
k = = K x 12
(Btu)(in)
(ft 2 )(hr)(°F)
(Btu)(ft)
(ft 2 )(hr)(°F)
K =
r =
(ft 2 )(hr)(°F)
(Btu)(in)
1
k