Buderus 21, 22, Towel Warmers Design Manual

Panel Radiators

Design Manual

For Buderus Panel Radiator models:

- Model 21

- Model 22

- Towel Warmers

Panel Radiator
Design Manual

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Panel Radiator Design Manual | 12.2009

Applications manual

Panel Radiator
Design Manual

Table of Contents

1 General Info 5

2 Safety 6

3 Product Description 7

4 Mounting Guidelines 15

5 Radiator Output Ratings 17

6 Radiator Selection Procedure 21

7 Piping Arrangements 22

8 Buderus NB Style Towel Racks 32

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Panel Radiator
Design Manual

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Technical specications are subject to change without prior notice

Panel Radiator Design Manual | 12.2009

Applications manual

1. General information

Panel Radiator
Design Manual

1.1. This manual

This application manual is intended for engineers,
architects, contractors, and installers. It provides

specication on panel radiator and towel rack models,

sizing information, and system layout assistance for

hydronic heating systems with panel radiators.

This manual describes the basic operation of the Buderus
panel radiators and towel racks, thermostatic controls and

piping accessories. It also provides rough in dimensions
and installation procedures.

Radiator heating capacities are listed by model, height and
length and are based on different supply water

temperatures.

For added savings Buderus recommends running panel

radiator systems at reduced temperatures. When using a

condensing boiler, the system should be designed so that
the return water temperature makes the boiler condense

except on the coldest days of the year.

Dew point ue gases:

• Natural Gas: 130°F (55°C)

• #2 Fuel Oil: 118°F (48°C)

1.2. Standards, regulations and directives

It is the responsibility of the installer to ensure that the

system corresponds to all current regulations and rules.

General guide lines are discussed with respect to sizing

and radiator selection. The design and radiator selection

process for one and two pipe heat distribution systems are
provided including examples. Quick and easy “rules of
thumb” for trouble free installation and operation are

presented.

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2. Safety

Panel Radiator
Design Manual

2.1. Layout of the instructions

Two levels of danger are identied and signied by the
following terms:

WARNING! RISK OF FATAL INJURY

Identies possible dangers emanating from

a product, which might cause serious injury
or death if appropriate care is not taken.

WARNING! RISK OF INJURY/SYSTEM

DAMAGE

Indicates a potentially dangerous situation
that could cause minor or moderately
serious injuries and damage to property.

Additional symbols for identication of dangers and user
instructions:

USER NOTE

User tips for optimal use of equipment and
adjustment as well as other useful information.

2.4. Disposal

● Dispose of the packaging in an environmentally
responsible manner.

— Dispose of defunct components through an

authorized agent in an environmentally

responsible manner.

2.2. Please follow these instructions

Only use original Buderus spare parts.

Damage caused by the use of parts not
supplied by Buderus is excluded from the

Buderus warranty.

2.3. Tools, materials and accessories

For the installation of panel radiators and towel racks,
you will need standard tools used for central heating,
boiler and DHW water systems.

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Panel Radiator
Design Manual

3. Product Description

With the line of panel radiators Buderus offers a real
alternative to conventional baseboard heating. For
decades Europeans have enjoyed the unsurpassed
comfort and versatility of radiant heat that is more exible,
efcient, and a cleaner alternative to baseboard heating.
Unlike conventional baseboard heat that provides only

convection heat, the high performance hydronic steel

panel radiators provide the perfect combination of both
convective and radiant heat while offering signicant
savings from lower water temperatures.

Radiant Heat vs. Convection Heat:

Forced hot air or baseboard systems with n tubes
produce heat that warms the air by convection, which
requires high water temperatures to effectively output
BTU. This results in large temperature differentials in the

room, can cause drafty conditions, and in many cases
results in hot air collecting at the ceiling and cooler air at

oor level.

Radiant heat, like the sun, warms objects rather than just
the air, creating a greater sense of warmth while requiring
lower room temperatures. The added radiant component
from panel radiators may permit return water
temperatures below 130°F (55°C) for natural gas and
118°F (48°C) for oil red appliances, allowing a
condensing boiler to condense and take advantage of its
added efciency.

Because Buderus radiators don’t turn “on and off”
randomly in the way traditional baseboards do, they are
virtually silent — eliminating the noise associated with

other heating systems.

The exibility of Buderus panel radiators offers builders,
designers, and homeowners a variety of sizes for any

heating and design requirement. These space-saving

panel radiators require between a third to a quarter of the
space of baseboard heating and are a perfect solution
where design exibility is important. The radiator’s unique
wall-mounted and optional oor-mounted styling also
minimizes areas where dust and dirt can collect and
allows for greater exibility in furniture placement.

Panel radiators from Buderus are stocked in several
heights and lengths, and in two widths.

Each panel radiator includes side panels, front and back
grill covers, and a owsetter valve. This feature enables
the system installer to quickly and easily regulate the
water ow through the radiator room by room. The result

is a consistent, even heat throughout all panel units in the

house — no more feeling warm in one room and chilly in

another.

Buderus Panel Radiators

Buderus “solidoux N” panel radiators are manufactured
from 18 Gauge (0.049”/0.125mm) steel panels. They
consist of water lled welded steel panels with convector
channels mounted on the back. These layers are
combined and arranged into two basic models:
model # 21 (width 2.5"), model # 22 (width 4.0").

Standard equipment with each radiator include wall
mounting brackets, bottom piping connections, built in
manual air vents, a drain plug and a ow setter valve with

a protective cover over it.

All stocking models have the ow setter (control) valve
and piping on the same side, and can be mounted facing

left or right.

Available Models

Model 21 Table 1

Dimensions Dry weight Water volume

H x L x W lbs kg gal liters

12"x24"x2"

12"x36"x2"

12"x48"x2"

12"x59"x2" 50 23 1.6 6.3

12"x63"x2" 54 24 1.8 6.7

12"x71"x2" 60 27 2.0 7.6

20"x24"x2" 35 16 1.0 3.8

20"x36"x2" 52 24 1.5 5.8

20"x48"x2" 69 31 2.0 7.7

20"x59"x2" 85 39 2.5 9.4

20"x63"x2" 91 41 2.6 10.1

20"x71"x2" 102 47 3.0 11.4

20 9 0.7 2.6

31 14 1.0 3.8

41 19 1.3 5.1

Special order sizes, up to 3‘ high and 10‘ long, are
available with a 4 to 6 week lead-time.

Buderus panel radiators come in a multi-layered, powder
coat enamel white nish that is durable, easy to clean

and ideal for most existing color schemes. They can also

easily be custom painted to any desired color.

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

24"x24"x2" 41 19 1.2 4.5

24"x36"x2" 62 28 1.7 6.7

24"x48"x2" 83 38 2.3 8.9

24"x59"x2" 102 46 2.9 10.9

24"x63"x2" 108 49 3.1 11.7

24"x71"x2" 122 56 3.4 13.2

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Panel Radiator
Design Manual

Buderus Towel Warmers

Model 22 Table 2

Dimensions Dry weight Water volume

H x L x W lbs kg gal liters

12"x16"x4"

12"x24"x4"

12"x36"x4"

12"x48"x4" 48 22 1.3 5.1

12"x63"x4" 63 28 1.8 6.7

12"x71"x4" 71 32 2.0 7.6

20"x16"x4" 27 12 0.7 2.6

20"x24"x4" 41 19 1.0 3.8

20"x36"x4" 62 28 1.5 5.8

20"x48"x4" 82 37 2.0 7.7

20"x59"x4" 101 46 2.5 9.4

20"x63"x4" 108 49 2.6 10.1

20"x71"x4" 121 121 3.0 11.4

24"x16"x4" 33 15 0.8 3.0

24"x24"x4" 49 22 1.2 4.5

24"x36"x4" 74 34 1.7 6.7

24"x48"x4" 98 45 2.3 8.9

24"x59"x4" 121 55 2.9 10.9

24"x63"x4" 129 59 3.1 11.7

24"x71"x4" 146 66 3.4 13.2

16 7 0.4 1.7

24 11 0.7 2.6

36 16 1.0 3.8

Nothing is more comforting than a warm towel after a
bath or shower. European towel warmers from Buderus
are the perfect combination of contemporary styling and
economical luxury. Towel warmers are also an excellent
way to add heat and remove humidity and dampness
from any bathroom.

Available in three sizes, the NB style towel warmers are
nished in a high quality white enamel for use in damp
environments like bathrooms. They should not be
installed in showers or areas where they are exposed to
direct water spraying.

The NB style is perfect for minimal space requirements
with a total depth of 5“ and a width of 24“. It is available in
heights of 32“, 48“ and 72“. These ready-to install towel
warmers offer outputs from 2,000 BTU/Hr to 4,500 BTU/
Hr at an average water temperature of 176ºF (80ºC).

All Buderus towel warmers have the water connections
on the bottom and a manual air vent at the top. Mounting
hardware is included. Piping accessories, valves and
thermostatic heads are available as accessories.

Buderus towel warmers must not be used with

potable water or open loop systems.

Chapter 5 has detailed radiator output ratings in table and

graphical form.

36"x16"x4" 48 22 1.1 4.2

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Panel Radiator Design Manual | 12.2009

Applications manual

Panel Radiator
Design Manual

Radiator Accessories

Buderus offers a variety of accessories for installation

and control of the radiators for different piping
arrangements.

Mounting Brackets

Buderus panel radiators include wall mounting brackets.
Floor mounting brackets are available as an accessory.

Rough in instructions and mounting guidelines are

presented in chapter 5.

Piping Connections

Each stocking radiator has 20 mm (approx. 3/4) metric
male tappings on the bottom on one side. The radiator
can be mounted with these connections facing left or
right. Figure 9 shows supply and return connections
which cannot be reversed. Buderus supplies the following
compression ttings for most applications.

Compression ttings are available from Buderus in sets
of two (see Table 3). These ttings are normally secured

to the piping connection on the radiator. When diverter or

shutoff valves are used, the compression ttings mount

on the valve.

Compression ttings for panel radiators Table 3

Pipe size and style Part #

½" copper

12 x 2 mm (⅜" PEX)

16 x 2 mm (½" PEX)

20 x 2 mm (¾" PEX) 1016879

⅝" copper

6198924

1016870

1016874

1646851

Additional accessories are available that help with the
installation of the panel radiator as well as the application
in which it is installed.

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Panel Radiator
Design Manual

Part no. 1016311

Straight Diverter Valve
w/ isolation valves for
panel radiators

Part no. 1016362

Straight Crossover
Valve w/ isolation
valves for panel
radiators

Part no. 3L602502

Pressure Bypass
Valve 3/4" male
thread for panel
radiators and towel
racks

Part no. 013G81013

Single Valve, angled
with adjustment
facing down for towel
racks; Head can be
replaced with
thermostatic head
#013G8250 or

Part no. 3L0143

Angled Return
Elbow with
isolation valve for
towel racks

Part no. 013G5002

Manual Adjuster
for panel padiators
and towel racks

Part no. 1016312
Angled Diverter
Valve w/ adjustable
bypass and isolation
valves for panel
radiators

Fig. 1 Valve/accessory dimensions in inches

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Part no. 013G8250

Danfoss
Thermostatic Head
for panel radiators

Part no. 82911060

Drain Valve w/
hose bib for panel
radiators

Panel Radiator Design Manual | 12.2009

Applications manual

Panel Radiator
Design Manual

Part no. 80262170

Straight Valve
w/ isolation valves
for panel radiators

Part no. 80262172

Angled Valve w/
isolation valves for
panel radiators

Part no. 82721124

Buderus Thermostatic
Head for panel
radiators and towel
racks

Part no. 013G8015

Single Valve, straight with adjustment at front for towel racks;
Head can be replaced with thermostatic head #013G8250
or #82721124

Part no. 013G8014

Single Valve, angled with adjustment at the front for towel
racks; Head can be replaced with thermostatic head
#013G8250 or #82721124

Part no. 82721180

Buderus Thermostatic
Head w/ remote
sensor for panel
radiators and towel
racks - capillary 79"
(2000 mm)

Fig. 2 Valve/accessory dimensions in inches continued

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Floor Brackets for panel radiators Table 4

Floor Brackets Part Number

Model numbers: 22 817-BUD

Model numbers: 21 817-BUD-1

Optional covers for brackets 81606400

Flow Setter Valve:

Each radiator is equipped with a ow setter valve
mounted on the same side as the water connections of
the panel radiator. This valve consists of two part integral
components for temperature control and ow balancing.

Flow Balancing:

Panel Radiator
Design Manual

Fig. 3 Flow setter valve adjustment

Flow balancing is done by adjustment of the ring marked
1-7 and N on the ow setter valve, lining the desired
setting up with the dimple in the rst ring. Turning of the
ring adjusts the diameter available for water ow. The N
marking indicates a fully open setting; the 1 marking
indicates nearly full restriction. The diagram on page 13
shows the pressure drop across the radiator as a function
of the ow rate and setting of the ow setter.

Air Vent and Drain Plug

Each radiator is equipped with a manual air vent (1/2”)
and removable drain plug (3/4”) for draining the radiator.
A at head screw driver is needed to open the air vent.

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Applications manual

Panel Radiator
Design Manual

Diverter Valves:

Straight (part number 1016311) and angled (part number

1016312) diverter valves are available from Buderus for
use in a one-pipe system (g. 4). Shut offs are located on
the supply and return branches to the radiator, allowing to
isolate the radiator from the piping system so it can be
drained and removed without decommissioning the

complete heating system.

Each diverter valve is factory set for 35 % ow through
the radiator and 65% through the bypass. Other ow
percentages are easily set according to the diagram (g.

5). To adjust the bypass, turn the spindle clockwise to the
fully closed position. Then open the bypass spindle the
desired number of turns from the fully closed position.
Refer to the chart that is on page 30, explaining the
pressure drop for a one-pipe system with diverter valves.
You will need to add up the pressure drop of radiator and
diverter valve when sizing the circulator.

Straight Valve

50

ADJUSTABLE
BYPASS

TO RADIATOR

TO RADIATOR

FROM RADIATOR

ISOLATION
VALVES

FROM RADIATOR

45

40

35

30

Radiator percentage of flow

50

45

40

35

30

Radiator percentage of flow

¾

Fig. 5 Setting for Straight and Angled diverter valves

1

Number of turns

Angle Valve

1¼ 1½ 1¾

1

Number of turns

2 3

Factory setting

Factory setting

ADJUSTABLE
BYPASS

ISOLATION
VALVES

Fig. 4 Straight and Angled Diverter Valves

Installation considerations:

1. The valve mounts directly to the supply and return

of the radiator. The compression ttings now

connect to the diverter valve.

2. Allow 5” oor clearance below the radiator for the
straight; 4” for the angled diverter valve.

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| 13

Thermostatic Sensor head:

Adding a Buderus Thermostatic Head enables room-by­room zone control for optimum comfort and efciency. It
is easily installed on the ow setter valve.

A thermostatic head with remote sensor is available for
locations where the valve head would be covered behind
a curtain or otherwise blocked from sensing the actual
room temperature. Length of the capillary: 79“ (2000
mm).

Panel Radiator
Design Manual

4

3

Buderus

2

Buderus

Temperature Control:

Thermostatic control head is mounted on the ow setter
valve of panel radiators and towel racks, and through its
capillary expansion controls the ow rate and therefore

the heat output of the panel. When using the thermostatic

head the ow setter valve needs to be in the N position. A
moveable, spring-loaded seat assembly inside the ow
setter valve regulates the water ow through thermostatic

action of the control head. This thermostatic head is
required for individual temperature control at each
radiator. The asterics provides frost protection of the
panel itself provided the heating system is operational.

The sensor indicator numbers correspond to the following
approximate temperatures:

Thermostatic Sensor Head Setting Table 5

Dial * 1 2 3 4 5

Room Temperature °F 40 57 63 68 73 79

Room Temperature °C 5 14 17 20 23 26

1

Fig. 6 Thermostatic Sensor Head

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Panel Radiator Design Manual | 12.2009

Applications manual

4. Mounting Guidelines

Panel Radiator
Design Manual

Panel Radiator Installation

Both model 21 and 22 radiators can be wall or oor
mounted. All wall brackets must be secured to studs or
other supports of sufcient strength for panel radiator
weight. Radiators with a length of 71" or less require 2
brackets (1 set); lengths 79” or larger require 2 sets.

Note: Do not attempt to mount radiators soley to sheet
rock or similar material.

Radiator Clearance Requirements:

Clearance for right hand radiators Table 6

Clearance
dimensions

Floor 2" (51mm)

Minimum
clearance

4" (102mm)

5" (127mm)

5" (127mm)

Reason

- No diverter valves

- Angled diverters

- Straight diverters

- Cross-over valves

Model 21 and 22: Wall Mounting

Each bracket is supplied with a slotted plastic locating
clip. Position brackets evenly along the radiator and at
least 4" in from either side for aesthetic reasons. The
bottom of the radiator rests 5/8" above the bottom edge
of the bracket. The radiator wall clearance can be set at
1-9/16" or 2-1/16" depending on the orientation of the

plastic locating clips. Piping connections are located at

1-3/16" return and 3-3/16” (supply) in from the valve side
of the radiator. The piping wall offset is 3-9/16" or 4-1/16"
for both Model 21 and 22 radiators. For left hand

radiators, measure these dimensions from the left side.

See Fig. 8 and 9 for details.

Mount the brackets to studs or other wall supports
capable of carrying the load of the full radiator (see
Tables 1 & 2). Use at least 2 screws per bracket. Pull the
T-shaped plastic securing plate forward and slide the top
holder upward.

Insert the radiator with the bottom edge into the locating
clip at the bottom of the bracket. Now slide the top
bracket down to secure the radiator in place. Refer to the
installation instructions included with the brackets for

details.

Side of

owsetter

valve

Side opposing

the owsetter

valve

Top 2" - 4"

2" - 4"
(51-102mm)

(51-102mm)

5" (127mm) Thermostatic Sensor Head

Access to manual air

bleeder

Access to the top of wall
bracket

Model 21 and 22: Floor Mounting

Floor brackets permit placement of Model 21 and 22
radiators in front of tall windows or where wall mounting
is not an option. These brackets include a oor pedestal

mount, radiator support, channel section and tightening

assembly. The top grille of the radiator must be removed
to install the channel section and tightening assembly.
Radiators are adjustable in height from 4” to 8” bottom

clearance.

Fig. 7 Floor mounting bracket

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Panel Radiator
Design Manual

Finished wall

2½"

Minimum of

4"

Bracket

1⁹/₁₆"

or

2¹/₁₆"

Panel Radiator

Bracket

TOP VIEW

Fig. 8 Model 21 Panel Radiator Rough in Dimensions in inches for wall mounting

Finished wall

Supply

Stud

Minimum of

4"

Return

2" 1³/16"

Stud

2⅝" from
finished
wall to
center of
tapings

1 2

Minimum of

4"

Bracket

4"

1⁹/₁₆"

or

2¹/₁₆"

Panel Radiator

Bracket

TOP VIEW

Fig. 9 Model 22 Panel Radiator Rough in Dimensions in inches for wall mounting

Supply

Minimum

of 4"

Return

2"

1³/

3⅜" from
finished
wall to
center of
tapings

1 2

16"

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Panel Radiator Design Manual | 12.2009

Applications manual

5. Radiator Output Ratings

Outputs depend on panel radiator size, average water

temperature, and room temperature.

Four examples are presented below to illustrate a range

of options. If none of them applies, use Figure 10 and

Table 9 to determine output based on individual

requirements.

Tables 7 and 8 show the outputs of Model 21 and 22
in-stock radiators at four different water temperatures.
Use the high temperature column if restricted in wall
space. To maximize efciency in condensing boiler
applications, ensure the return water temperature drops
below the ue gas’ dew point of 131°F (55°C) for
signicant periods of the heating season.

2½

Radiator outputs in BTU/Hr:

Panel Radiator
Design Manual

Model 21: 2½" (63.5mm) deep Table 7

Output BTU/hr

Supply 194°F (90°C) 176°F (80°C) 158°F (70°C) 140°F (60°C) Part Number

Delta T 36°F (20°C) 36°F (20°C) 18°F (10°C) 18°F (10°C)

12"x24"x2½"

12"x36"x2½"

12"x48"x2½"

12"x59"x2½" 4700 3700 3200 2300 3-41259

12"x71"x2½" 5700 4500 4000 2900 3-41271

20"x24"x2½" 2800 2200 1900 1400 3-42024

20"x36"x2½" 4200 3300 2900 2100 3-42036

20"x48"x2½" 5600 4400 3900 2800 3-42048

20"x59"x2½" 7000 5500 4800 3500 3-42059

20"x71"x2½" 8400 6600 5800 4200 3-42071

24"x24"x2½" 3200 2500 2200 1600 3-42424

24"x36"x2½" 4900 3800 3400 2400 3-42436

24"x48"x2½" 6500 5100 4500 3200 3-42448

24"x59"x2½" 8100 6300 5600 4000 3-42459

24"x63"x2½" 8700 6800 6000 4300

24"x71"x2½" 9700 7600 6700 4800 3-42471

1900 1500 1300 1000 3-41224

2900 2300 2000 1400 3-41236

3800 3000 2600 1900 3-41248

All values based on 68°F (20°C) room temperature.

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

| 17

Panel Radiator
Design Manual

Model 22: 4" (100mm) deep Table 8

Output BTU/hr

Supply 194°F (90°C) 176°F (80°C) 158°F (70°C) 140°F (60°C) Part Number

Delta T 36°F (20°C) 36°F (20°C) 18°F (10°C) 18°F (10°C)

12"x16"x4"

12"x24"x4"

12"x36"x4"

12"x48"x4" 4900 3800 3400 2400 3-21248

12"x63"x4" 6500 5100 4500 3300 3-21263

12"x71"x4" 7300 5800 5100 3700 3-21271

20"x16"x4" 2500 2000 1700 1200 3-22016

20"x24"x4" 3700 2900 2600 1900 3-22024

20"x36"x4" 5600 4400 3900 2800 3-22036

20"x48"x4" 7500 5900 5200 3700 3-22048

20"x59"x4" 9300 7300 6400 4600 3-22059

20"x71"x4" 11200 8800 7800 5600 3-22071

24"x16"x4" 2900 2300 2000 1400 3-22416

24"x24"x4" 4300 3400 3000 2200 3-22424

24"x36"x4" 6500 5100 4500 3200 3-22436

24"x48"x4" 8700 6800 6000 4300 3-22448

24"x59"x4" 10800 8400 7400 5300 3-22459

24"x71"x4" 13000 10200 9000 6500 3-22471

36"x16"x4" 3500 2700 2400 1700 3-23616

1600 1300 1100 800 3-21216

2400 1900 1700 1200 3-21224

3700 2900 2500 1800 3-21236

All values based on 68°F (20°C) room temperature.

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Panel Radiator Design Manual | 12.2009

Applications manual

If tables 7 and 8 do not match a system‘s requirements,
the following guidelines provide means to calculate the
effects of ambient room temperature, supply water

temperature and temperature drop through the radiator
on the radiator output.

Ambient room temperature effect: The (adjusted)
output of a radiator at any room temperature (∆T room)
can be computed from the output listed at a room
temperature of 68°F (20°C) as:

Adjusted Output = Listed Output x [1+α x (68-Troom)]
(Troom in °F) where α is a correction factor computed as:

α = 1.385 / (ΔT supply - 75) with ΔT supply in °F.

Note: The listed radiator output depends on the supply
temperature.

Example: Select the proper radiator to heat a porch

which is to be kept at 55°F (13°C) during the winter.
Maximum heat loss is 8,750 Btu/hr. Assume supply
temperature equal to 194°F (90°C).

Panel Radiator
Design Manual

Solution: The larger temperature difference between the

radiator and the porch increases the radiator output. To

nd the proper size radiator, we must compute the listed
output at 68°F (20°C).
Adjusted Output = 8,750 Btu/hr at 194°F (90°C) and 55°F
(13°C). (∆T room).

Compute correction factor α as:

α = 1.385 / (194 - 75) = 0.0116

Listed Output = 8,750 / [1 + (0.0116 x (68 - 55)] =
7,560 Btu/hr
From Table 8: Use Model 22 20” x 48” x 4“ instead of
Model 22 24” x 48” x 4“ (listed output = 7,500 Btu/hr).

This ambient room temperature effect is generally small
and need only be considered in system design if desired
room temperatures are well beyond the typical 68 - 72°F
(20 - 22°C) range.

Supply water temperature effect: The effect of different
supply temperatures on the output of panel radiators is

computed using the conversion factors of Table 9 or read
directly from the Performance Curves in Figure 10.

Table 9 contains conversion factors needed to compute
the adjusted radiator output from the listed ratings. The
∆T factor is computed as the difference between the
average water temperature and room temperature.

Fig. 10 Performance Curves Model 22 Radiators

Conversion Factors Table 9

∆ T in ºF (°C) Conversion Factor

10 (6) 0.045

20 (11) 0.112

30 (17) 0.198

40 (22) 0.275

50 (28) 0.367

60 (33) 0.466

70 (39) 0.569

80 (44) 0.677

90 (50) 0.789

100 (56) 0.905

108 (60) 1.000

110 (61) 1.024

120 (67) 1.147

130 (72) 1.272

140 (78) 1.401

150 (83) 1.535

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

| 19

Example: Compute the output of a Model 21 20” x 59”
radiator with an average water temperature of 140°F
(60°C) in the radiator and a room temperature of 70°F
(21°C).

Solution: Listed output = 7,000 Btu/hr (See Table 9)
∆T = 140 - 70 = 70°F: Conversion Factor = 0.569 (See
Table 9) Adjusted output = 0.569 x 7,000 = 3,983 Btu/hr.

Comment: The effect of the ambient room temperature is

already accounted for in the conversion factors listed in

Table 9. Figure 10 contains the performance curves for
Model 22 radiators showing the output per linear foot of

radiation for the different heights as a function of supply
temperature.

Different curves are shown based on a 18°F (10°C) and
36°F (20°C) temperature drop through the radiator and a
68°F (20°C) room temperature.

Example: A room requires 12,000 Btu/hr with 6 ft of
available space. Maximum supply temperature is 170°F
(77°C). What model(s) can be used for this application?

Panel Radiator
Design Manual

Solution: Required heat output per foot = 12,000/6 =
2,000 Btu/hr per linear foot. Check Figure 10 at 170°F
(77°C) supply temperature and 2,000 Btu/hr Output:

Model 22: Use 24” high with about 18°F (10°C) ∆T drop.

2 0 |

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Panel Radiator Design Manual | 12.2009

Applications manual

6. Radiator Selection Procedure

Several factors must be considered in the selection of a
panel radiator. These are:

• Heat loss of the room.

• Location of the radiator(s) and available oor to

window height.

• Desired piping arrangement.

• Room usage.

• Type of room control used.

All factors are discussed below and must be given
consideration prior to nal radiator size and model

selection.

1. The panel radiator(s) must have at least the required

capacity to match the heat loss. Oversizing is not a

problem provided thermostatic sensor heads or other

temperature sensitive controls are used to cycle the heat
off once the desired room temperature is reached.

Panel Radiator
Design Manual

2. Radiators are frequently selected based on the
intended location. A 3’ radiator ts nicely under a 36”
window, whereas a 24” radiator may only be needed
based on the heat loss. Window size and number of
windows as well as overall room size affect the selection
process. Once a room exceeds 12’ x 12’, it is advisable to
install 2 smaller radiators on outside walls for more

comfort.

3. The selected piping arrangement affects the radiator
sizing on monoow or one-pipe diverter valve based
systems, because the supply temperature reduces with
distance from the boiler. Minor oversizing of the last
radiators in the one-pipe system may be necessary.

4. For rooms that are used occasionally where a rapid
heat-up is required, it is advisable to install some extra
radiation. This becomes important on heating systems
operating with outdoor reset control. There is no need for

over sizing radiation in main living areas as they are
generally maintained at uniform temperatures.

5. Radiators equipped with thermostatic sensor heads on

a constant circulation system maintain a more uniform
room temperature and respond faster to temperature

disturbances such as open doors or windows, solar or

internal heat gain from appliances, lights, etc. compared
to a centrally located thermostat system.

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

| 21

Panel Radiator
Design Manual

7. Piping Arrangements

The design of a panel radiator based heating system

involves selection of a piping system, pipe sizes, overall

design temperature drop, required ow rates and desired
type of system control. For trouble-free system operation,
do not exceed the ow rates in Table 10.

Maximum ow rates & heat carrying capacities Table 10

Pipe size* Max

½" copper
or PEX

⅝" PEX 2.0 20,000 30,000 40,000

¾" copper 4.0 40,000 60,000 80,000

1" copper 8.0 80,000 120,000 160,000

1¼" copper 14.0 140,000 210,000 280,000

Diverter
valve

Radiator

Flow

ow
(gpm)

1.5 15,000 22,500 30,000

2.0 20,000 30,000 40,000

2.5 25,000 37,500 50,000

Note: Q (∆T = 20°F (11°C)) denotes the maximum heat
load carrying capacity based on a 20°F (11°C)

temperature drop.

*Pipe size used for main supply/return piping in multiple
one-pipe diverter valve based systems or for one-pipe
systems using monoow tees. This information is useful
for pipe sizing in two-pipe distribution systems.

This chapter discusses several piping arrangements,
guidelines for system design, pipe size, pump selection

and ne-tuning of individual components. Heat loss (Q),
water ow rate (GPM) and temperature drop (∆T) through
a hydronic heating system are related to each other as:

Q = 500 x GPM x ∆T

This equation is used extensively for accurate sizing of
radiators.

Q

(∆T=20ºF)Q(∆T=30ºF)Q(∆T=40ºF)

One-Pipe System Options

Figure 11 presents three different one-pipe
arrangements. In any one-pipe system, a single pipe

connects all radiators together. Fewer materials are
needed in a one-pipe system where a perimeter loop
supplies water to all radiators. Since water may ow
through all radiators and cools off along the way, it is
necessary to oversize the last radiator(s) in the loop. A

sizing procedure is outlined.

Table 10 shows maximum Btu load on a one-pipe system
based on pipe size and overall temperature drop.

Series loop system

All water ows through all radiators.

A thermostatic head cannot be used on any radiator as it
will shut off all ow. A central thermostat is required for

temperature control. Do not exceed heat loads as listed

in Table 10.

Option 1: one-pipe system with monoow tees
(Fig 11).

Monoow tees are used to divert some water from the
main loop into each radiator. Use one monoow tee on
the return if the radiator(s) are located above the main
loop; use two monoow tees if the radiators are installed
below the main loop. Place the tees in the main loop to
each radiator at least 12” apart. Thermostatic heads on

each radiator provide very easy means for individual

temperature control. The system can be operated off a
central thermostat or with constant circulation using an
outdoor reset system. Size the main loop based on the
selected temperature drop (20°F, 30°F, or 40°F (11°C,
17°C, 22°C)) and heat load. Make sure to oversize the
last radiators properly, especially when using an overall
temperature drop of 30°F (17°C) or 40°F (22°C). It is

important to size the main supply and return pipes for the

total heat load and volume to avoid ow restriction or

noise.

Option 2: one-pipe system with diverter valves

(Fig 12).

This arrangement is similar to using monoow tees
except that now each radiator is equipped with a diverter
valve. Secondly, the total loop ow can NOT exceed 2
GPM because of possible noise at greater ow rates. The
bypass adjustment in the diverter valve can be used to
throttle down the ow through the rst radiators and
increase ow through the last radiators in the loop to
make up for the drop in loop temperature. Thermostatic

heads on each radiator provide an easy means for
individual temperature control. The system

can operate off a central thermostat or with constant
circulation using an outdoor reset system. Follow Table

10 for pipe sizing. It is important to size the main supply
and return pipes for the total heat load and volume to

avoid ow restriction or noise.

2 2 |

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Panel Radiator Design Manual | 12.2009

Applications manual

Option 3: Multiple one-pipe systems.

Options 2 and 3 above can be installed in a multiple loop
fashion where several one-pipe systems are connected
between a common supply and return manifold. Assure
adequate ow in all piping systems when using monoow
loops and/or diverter valve loops. Isolation and balancing

valves are recommended on each loop for service and

ow control.

A properly sized pump operating on constant circulation

can supply water to all loops. A single Grundfos UP15-42
or equivalent can handle up to 3 diverter valve loops; use
a Grundfos UP26-64 or equivalent for 4 to 6 loops. Size
the main piping for the combined ow in all branches,

Option 1: One-Pipe System with Venturi Tees or Monoflow Tees.

1 2

Panel Radiator
Design Manual

following the guidelines in Table 10. Refer to the Pressure
Drop Curves (Fig. 14 & 15) on pages 30 & 31 for
estimating the pressure drop through each radiator when
using monoow tees. Use the Pressure Drop Diagram on
page 30 for a one-pipe system with diverter valves. Use
the approximate ow rate through the radiator and ow

setter valve setting to read off the pressure drop. Size the

circulator based on total ow and overall system pressure

drop. Thermostatic heads are required in this
arrangement for individual temperature control.

Ensure all supply and return piping is sized properly to

avoid restriction and noise.

1 2

1 2

Option 2: One-Pipe System with Diverter Valves.

1 2

Option 3: Multiple One-Pipe System (Home Run).

1 2

1 2

1 2

1 2

1 2

Drawing not to scale

Fig. 11 One-Pipe System Options

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| 23

Panel Radiator
Design Manual

Design procedure for One-Pipe System with

monoow tees or diverter valves

1. Select radiator hook-up sequence.

2. Determine individual heat loads.

3. Determine linear footage of wall space available for

each radiator.

4. Compute the required heat load per foot for each

room.

5. Select system temperature drop ∆T = 20, 30 or 40°F
(11°C, 17°C, 22°C) and maximum supply temperature.

6. Compute the total heat load (Q) in the loop by adding

the individual heat loads.

7. Determine loop ow rate from total heat load (Q) and
selected ∆T as: GPM (loop) = Q / 500 / ∆T

8. Compute the supply temperature for each room based

on the supply temperature and heat load of the

previous room and the total loop ow rate (GPM) as:

New Supply Temp = Previous Supply Temp - (Q room)
/ 500 / GPM

With the supply temperature computed in Step 8 and the
linear heat load in Step 4, refer to Figure 10 to nd the
required radiator size, or tables 9 and 10 for the total

individual radiator output if the any of the four examples

applies. Use the same ∆T value in reading from the
curves in Figure 10 as the selected value in Step 5. In
case more than one radiator is to be installed in a room,
size all radiators based on the above procedure.

Table 11

1 Select

room
sequence

2 Heat load

per room

3 (BTU/hr)

4 Available

wall space
(ft)

5 Minimum

Required

Heat Load

per linear

ft (BTU/ft)

6 Total

heat load

(BTU/ft)

7 Total loop

GPM GPM(loop) = Q / 500 / ΔT = ____ GPM

8 Supply

temp per
room

9 List

possible

radiator
Models
and sizes

Room 1 Room 2 Room 3 Room 4

ΔT =___ºF Supply temp(room1)
=max supply temp
= _______ ºF

Q = __________BTU/Hr

____ºF ____ºF ____ºF ____ºF

2 4 |

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Panel Radiator Design Manual | 12.2009

Applications manual

Panel Radiator
Design Manual

Example: One-Pipe System Layout

Design a one-pipe system for a second oor with
individual room temperature control:

Table 12

Description Heat Load Window

Size

Bathroom 3,000 1x3 ft wide rst

Master Bedroom 9,000 2x4 ft wide second

Bedroom 2 6,000 1x3 ft wide third

Bedroom 3 4,000 1x3 ft wide fourth

Hook-up
Sequence

Solution:

Step 1. Complete the Radiator Sizing Sheet to nd

minimum size radiator.

Step 2. Select control strategy and size piping and pump

using Table 7.

Step 3-4: See Table 13.

Step 5: Assume temperature drop (∆T) = 30°F (17°C),

maximum supply temperature = 180°F (82°C).

Results: Output/ft Radiator Models

Bedroom Supply Temp = 180°F (82°C) 1500 Btu/ft
#22 20”
M. Bedroom Supply Temp = 176°F (80°C) 1125 Btu/ft

#22 x 12

Bedroom #2 Supply Temp = 164°F (70°C) 2000 Btu/ft
#22 24”
Bedroom #3 Supply Temp = 156°F (60°C) 1333 Btu/ft
#22 24”

Use 5/8 ” PEX and diverter valves (or: 3/4” copper main
line with 3/4” x 3/4” x 1/2” monoow tees) with

thermostatic heads on all radiators for individual room

control. Place a thermostat in the bathroom or master
bedroom or run constant circulation. Use a Grundfos
UP15-42, a Taco 007, or equivalent pump with a
balancing valve to throttle the ow. Noise may otherwise

develop in the diverter valves.

Table 13

1 Select

room
sequence

2 Heat load

per room

Bathroom Master

Bedroom

3000 9000 6000 4000

Bedroom 2Bedroom

3

Step 6: Add all heat loads from row 2 and enter in Step 6.

Step 7: Compute ow rate in the one-pipe system in

GPM.

The ow rate can not exceed 2 GPM when
using diverter valves. Using a larger ∆T lowers

the GPM.

Step 8: Here we must compute the supply temperature

for each room. Start with the rst room and
compute each supply temperature step by step
as shown here.

Supply Temp (1) = 180°F (82°C)

Supply Temp (2) = 180 - 3000 / (500 x 1.47) = 176°F
(80°C)

Supply Temp (3) = 176 - 9000 / (500 x 1.47) = 164°F
(70°C)

Supply Temp (4) = 164 - 6000 / (500 x 1.47) = 156°F
(60°C)

Step 9: Now with each value computed in steps 4 and 8,

locate those values in Fig. 10. The output curve

located directly above that point identies the
minimum size radiator required. Use the 18°F
(10°C) ∆T curves if designing for a 20 to 30°F (11
to 17°C) temperature drop, use the 36°F (20°C)
∆T curves if designing for a 40°F (22°C) drop.

3 Available

wall space
(ft)

4 Minimum

required
heat
load per
linear foot

(BTU/ft)

5 Minimum

Required

Heat Load

per linear

ft (BTU/ft)

6 Total

heat load

(BTU/ft)

7 Total loop

GPM GPM = Q / 500 / ΔT = 22000 / 500 / 30 = 1.5 GPM

8 Supply

temp per
room

9 Possible

radiator
Models
and sizes

2 8 3 3

1500 1125 2000 1333

ΔT = 30ºF
Supply temperature (room1)
=max supply temperature
= 180 ºF

Q = 3000 + 9000 + 6000 + 4000 = 22000 BTU/Hr

ΔT = Q / 500 / GPM

180 176 164 156

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

| 25

Two-Pipe System Options

Figure 12 illustrates two common two-pipe congurations.

Option 4: Two-Pipe Direct Return System

1 2

Option 5: Two-Pipe Reverse Return System

1 2

Panel Radiator
Design Manual

1 2

1 2

1 2

1 2

Pressure Bypass Valve

Drawing not to scale

Fig. 12 Two-pipe System Options

Benets of Two-Pipe Systems:

1. Each radiator is supplied with the same
temperature water maximizing radiator output.

2. No limit to the number of radiators on a two pipe
system loop; the supply and return mains must be sized
for maximum ow. Follow the guidelines in Table 10 for
sizing the supply and return runs. Use 1/2” copper or
PEX tubing to connect radiators to main runs.

3. Individual radiator control is easily done using
thermostatic sensor heads. Use constant circulation with

outdoor reset control for optimum system performance. A

central thermostat can be used for on/off control;
however, thermostat location governs overall system

control and may override individual room control.

Requirements for Two-Pipe System:

• Two main distribution pipes are needed; one for

the supply to the radiators and a second pipe for the

return to the boiler.

• A pressure actuated bypass valve (Part No.
3L602502 for a 3/4” Danfoss valve) connected between

supply and return mains is necessary on constant

circulation systems with thermostatically controlled
radiators to prevent dead-heading the pump. This bypass

valve is not needed on thermostat controlled systems if

the radiators are not equipped with thermostatic sensor

heads.

2 6 |

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Panel Radiator Design Manual | 12.2009

Applications manual

Design Procedure for Two-Pipe System

1. Determine individual heat loads.

2. Select desired overall temperature drop of systems

(∆T); i.e. 20°F (11°C), 30°F (17°C) or 40°F (22°C).

3. Compute loop ow rate GPM from:
GPM = Q / 500 / ∆T

4. Use Figure 10 or the Conversion Factors in Table 9 to
determine output of radiator models in case of lower

supply temperatures.

5. Use the Pressure Drop Chart on pages 30-31 as a
guide to set the ow setter valve for each radiator to
ensure proper ow through each radiator. Adjust ow
setter valves as needed based on system
performance. Close down the ow setter on “hot”
radiators by dialing in a lower setting on the adjustment
ring, or adjust the ow setter to a higher setting for
“cool” radiators.

6. Size piping based on system ow rate; size circulator
based on ow rate and overall system pressure drop.

Panel Radiator
Design Manual

Table 14

1 Select

room
sequence

2 Heat load

per room

3 (BTU/hr)

4 Available

wall space
(ft)

5 Minimum

Required

Heat Load

per linear

ft (BTU/ft)

6 Total

heat load

(BTU/ft)

7 Total loop

GPM GPM(loop) = Q / (500xΔT) = ______ GPM

Room 1 Room 2 Room 3 Room 4

ΔT =___ºF Supply temp(room1) =max supply
temp= _______ ºF

Q = __________BTU/Hr

8 Supply

temp per
room

9 List

possible

radiator
Models
and sizes

____ºF ____ºF ____ºF ____ºF

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

| 27

Panel Radiator
Design Manual

Example 2: Two-pipe System Lay-out

Design and select a two pipe panel radiator system with
the following requirements:

Table 15

Description Heat Load Window

Size

Walk-in closet 2,000 none

Bathroom 5,000 1x2 ft wide 2,500

Bedroom 1 8,000 2x3 ft wide 1,333

Bedroom 2 10,000 2x4 ft wide 1,250

Master Bedroom 12,000 2x4 ft wide 1,500

Required
BTU/ft

Total Load: 37,000 Btu/hr
System Parameters:
Maximum Supply Temperature: 194°F (90°C)
Thermostat in master bedroom for ON/OFF control.

Solution: Two-Pipe System Lay-out

1. If sufcient space is available for radiators, select
radiators based on required heat output and desired
style. Select radiators from Tables 9 & 10 since the

system temperature is similar to those listed.

Table 16: Radiator Option Determination Chart: Two-Pipe

System

Table 16

Descrip­tion

Walk-in
closet

Bathroom 5000 2,500 1x #22

Bedroom 18000 1,333 2x #22

Bedroom 210000 1,250 2x #22

Master
Bedroom

Heat
Load

2000 1 3-4

12000 1,500 2x #22

BTU/ftSelected

Models

20"x36"

12"x36"

12"x48"

20"x48"

No. and
length of
radiators

1x 3ft 6-7

2x 3ft 5-6

2x 4ft 6-7

2x 4ft 7-N

Flow­setter
valve

If the radiators must be sized for the available window

space, determine the minimum needed model radiator

based on the required Btu/ft for each room from Figure
10 with a 194°F (90°C) supply temperature. Use the
same supply temperature for each radiator in a two-pipe

system.

2. Select an overall temperature drop of 20°F (11°C).

3. Compute system ow rate as: GPM = Q / 500 / ∆T =
37000 / 500 / 20 = 3.7 GPM

4. Combine all information in tabular form as shown in
Table 2.

2 8 |

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Panel Radiator Design Manual | 12.2009

Applications manual

Panel Radiator
Design Manual

Balancing the system

Initial settings of ow setter valves will help to

ensure proper ow through all radiators.

Keep in mind that this is only a starting point
and that the system may require further

adjustment based on the heating

characteristics of the structure.

Procedure for setting the ow-setter valves.

1. Identify the largest radiator. In the above example it
would be the master bedroom radiator. The setting for
this radiator should be “N”. This radiator will have the
highest pressure drop and requires that the ow-setter
valve be fully open.

2.Using the Pressure Drop Chart on page 30-31, nd the
output for this radiator (at selected ∆T) at the bottom of
the chart. Based on 6,000 btu/hr at a 20°F ∆T the ow
rate for this radiator is 0.6 GPM. Follow the 0.6 GPM

line vertically until you intersect the N setting. Reading

across to the left you will see that the pressure drop for
this radiator is approximately 12 in. W.C. or 1ft/hd.

3. Draw a horizontal line across the diagram at 12 in.

W.C.

Piping Lay-out Suggestions:

1. For small systems, use one-pipe system with
monoow tees or diverter valves.

Btu’s per loop:
15,000 - 20,000 Btu/hr with 1/2 “ copper
20,000 - 30,000 Btu/hr with 5/8 “ PEX.

Increasing the overall temperature drop in the system

from 20°F (11°C) to 30°F (17°C) or 40°F (22°C)
permits more radiation per loop. (See Table 14).

Oversize radiators by 20 - 30% at the end of a one­pipe loop. Always install a balancing valve in each
loop to regulate the ow rate to eliminate possible ow

noise.

Maximum ow rate for diverter valves: 2 GPM
Maximum ow rate per radiator: 2.5 GPM.

2. For larger systems, use two-pipe reverse return or
multiple one-pipe systems with common supply and
return manifolds. Refer to Table 10 for pipe sizing.
Pump Selection:
1-3 loops: Grundfos UP15-42, Taco 007 or equivalent
3-6 loops: Grundfos 26-64 or equivalent
Use pressure bypass valve on two-pipe systems to

prevent deadheading the pump.

4. Select the next radiator. Identify its btu/hr output, locate
this gure at the bottom of the chart as you did for the
rst radiator. At the corresponding ow-rate, move

vertically on chart until you intersect the horizontal line

that you drew indicating 12” W.C. Find the appropriate
ow setting. If the value is between two settings, say 3
and 4, then simply set the valve between 3 and 4.

5. Repeat step 4 for remaining radiators.

6. Use guidelines in Table 10 to size main piping. In this
case, use 3/4” copper mains with 1/2” copper (or PEX)
to/from each radiator. Install a thermostat in master
bedroom. Size circulator based on total ow rate and
install balancing valve for ow control.

Radiator Selection & System Start-up Suggestions:

1. Size radiators based on heat load, location, available

space, desired style and system operating
temperatures.

2. Use of thermostatic sensor heads increases comfort,

eliminates problems with over sizing the radiation and

provides individual room control.

3. Balance the system to ensure proper heat output from
each radiator using the ow setter valve on each

radiator. Shut off thermostatic heads one at a time and

monitor system response. Make necessary
adjustments.

4. Retighten compression ttings slightly after initial

start-up.

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| 29

Pressure drop curves:

Panel Radiator
Design Manual

Settings on flowsetter

200

1 2 3 4 5 6 7 N

100

90
80
70
60

50

²

40

30

20

Pressure Drop in Inches H 0

10

9
8
7
6

5

4

0.05 0.08 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.9 1 2 3

BTU/Hr

500 1,000 2,000 5,000 10,000

BTU/Hr

750 1,500 3,000 7,500 15,000

BTU/Hr

1,000 2,000 4,000 10,000 20,000

Fig. 13

3 0 |

Technical specications are subject to change without prior notice

GPM

∆T = 20°F (10°C)

∆T = 30°F (15°C)

∆T = 40°F (20°C)

Panel Radiator Design Manual | 12.2009

Applications manual

% Radiator Flow

3

2

45

Panel Radiator
Design Manual

35

30

4050

Fig. 14

1

∆p Head in Feet

0.50 0.75 1.0 1.5 2.0 2.5 3.0 4.0
Circuit Flow - GPM

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

| 31

8. Buderus NB Style Towel Racks

Panel Radiator
Design Manual

The Noblesse style towel racks are attractively designed
with a vertical frame of two 2-3/4" round pipes connected
horizontally with 1” curved round steel tubing precision
welded in the interior. Two ½” NPT female tapings are
available on the bottom of the towel rack for the supply

and return. An air vent is already installed on the top right

of the NB towel rack. The NB has an adjustable offset of
3” and 4” from the wall.

All towel racks come in a multi-layered, powder coat
enamel white nish that is durable, easy to clean and

ideal for most existing color schemes. Supply and return

pipes are reversible. Openings in the towel rack are
provided to hang towels. Complete wall mounting
hardware and a manual air vent is supplied with each
towel rack.

For piping accessories available through Buderus for a
clean, nish installation see Figures 1 and 2.

NB Style towel rack stock sizes Table 17

Model # Dimensions

NB towel
rack

NB towel
rack

NB towel
rack

(height x
width)

24" x 32" 2,000 17 lbs. * NB2432

24" x 48" 3,000 25 lbs. * NB2448

24" x 71" 4,500 35 lbs. NB2471

BTU @

180º F

Approx.
Ship Wt.

Part NO.

* Item can be shipped via UPS

3 2 |

Technical specications are subject to change without prior notice

Panel Radiator Design Manual | 12.2009

Applications manual

Panel Radiator
Design Manual

Width - 24"

(installed)

Recommended Bracket

locations

16"

Bleeder

Finished

Wall

2"

Recommended bracket

spacing

32" Towel Rack - 25"
47" Towel Rack - 41"
72" Towel Rack - 65"

Adjustable

from

3" to 4"

½"

Taping

Recommended Bracket

location

21½"

center to center

½"

Taping

Top view

Recommended minimum

floor clearance 6"

Fig. 15 Buderus NB Style Towel Warmers

- Supply and Return tapings are interchangeable.

| 33

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

Panel Radiator
Design Manual

3 4 |

Technical specications are subject to change without prior notice

Panel Radiator Design Manual | 12.2009

Applications manual

Panel Radiator
Design Manual

Panel Radiator Design Manual | 12.2009 Technical specications are subject to change without prior notice

| 35

Bosch Thermotechnology Corporation
50 Wentworth Avenue
Londonderry, NH 03053
Tel.: [phone]
Fax: [phone]
www.buderus.net

Products manufactured by:
Bosch Thermotechnik GmbH
Sophienstrasse 30-32
D-35576 Wetzlar
www.buderus.de

Bosch Thermotechnology Corporation reserves the right to
make changes without notice due to continuing engineering

and technological advances.

BTC 451001101 A | 12.2009