Maxitrol M610H User Manual

Modulating Valves for Atmospheric, Infrared, and Direct Fired Burners

M/MR Series

TABLE OF CONTENTS

Introduction ................................................................ 2

Direct Fired Applications (Negative Pressure) ........... 2

Direct Fired Applications (Positive Pressure) ............ 3

Indirect Fired Applications ......................................... 3

‘H’ Sufx M/MR Valves .............................................. 3

Specications ............................................................ 4

Application Table ....................................................... 5

Dimensions ................................................................ 6

Capacities .................................................................. 7

Typical Gas Trains ..................................................... 8

Installation of MR410, MR510, & MR610 Valve ........ 8

M411, M511, M611
M420, M520, M620
MR410, MR510, MR610
MR212D, MR212E, MR212G
and MR212J (Flanged)
MR251D, MR251E, MR251G
M451, M551, M651

design certied

“H” sufx models for use with LP and other applica­ tions:M420H, M520H, M620H, MR410H-1, MR510H-1,
MR610H-1

Absolutely NO EXTERNAL MECHANICAL ACTIVATION

•

required.

MR Valve (only) performs dual function of modulation

•

and pressure regulation.

Provides innite, continuous ame adjustment.

•

May be factory installed or added in the eld.

•

Capacities to 30,000 CFH.

•

Available in a wide range of body styles and pipe sizes.

•

Designed for use with the Maxitrol Selectra

•

®

series of
modulation systems - or SC10 Signal Conditioners
convert computer/PLC controller signals if standard
Maxitrol companion controls are not specied.

Maintaining consistent temperatures is no longer a prob­lem. The unique Modulator or Modulator/Regulator valve,
the heart of the Selectra

®

Electronic Gas Flame Modu­lating System, provides precise, non-uctuating, instanta­neous temperature control - without requiring any motor or
mechanically driven buttery valve.

Figure 1 : MR212

Whether your needs are problem-free stabilized area
heating, elevated heating, consistent higher baking/drying
temperatures or other process applications.

© 2008 Maxitrol Company, All Rights Reserved

1

INTRODUCTION

DIRECT FIRED

To evaluate which valve will satisfy your needs, it is neces­sary to determine the application. The rst, and most basic
breakdown, is direct versus indirect red appliances.

Direct red units do not have a heat exchanger and all
products of combustion generated by the gas burning de­vice are released directly into the airstream being heated.
They are commonly used in space heating or make up air
applications, process drying, and baking ovens.

Direct red burners have raw gas injected into the burner
and the burner relies entirely on the air being pulled across
the burner for combustion air. It may take advantage of
the mixing effects of the blower by using a pull through
system which locates the burner on the suction side of
the blower. This means the air being pulled across the
burner is at a negative pressure (usually not greater than

-1.5” w.c.). Other direct red applications may use a push
through systems which locates the burner downstream
from the blower. This means the air being pushed across
the burner is at a positive pressure (usually not greater
than 3” w.c.)

Direct red burners can be of extremely high turn down ra­tios, in some instances, 30:1. The high turn down ratio al­lows the minimum temperature rise to be low enough that
the unit does not have to be cycled on and off to maintain
temperature.

Indirect red appliances utilize a heat exchanger and all
products of combustion generated by the gas burning de­vice are vented outdoors. They are usually supplied with
an atmospheric burner or a power burner.

The other burner is the atmospheric burner. The air being
supplied to this burner is at atmospheric pressure. They
have limited turndown ratios (maximum input: minimum
input) of usually 3:1 or 4:1. Due to limited turndown ratio,
the minimum temperature rise cannot be held low enough
and as a result, the main gas valve must usually be cycled
to maintain temperature.

A power burner is a burner in which either the gas, air,
or both are supplied at pressures exceeding line pressure
for gas and atmospheric pressure for air. Maintaining the
proper gas-air mixture for modulation usually requires
pressure control of both the air and gas. Burners of this
type are not capable of modulation with the Maxitrol Selec­tra® system.

Valves designed for direct red applications (negative

pressure/pull through) M411, M511, M611, MR212D,
MR212E, MR212G, and MR212J

These valves are designed exclusively for negative pres­sure (pull through) applications. They use a counter spring
to keep the valve in the close position despite the down­ward pull of negative pressure. M411, M511, and M611
valves are set for applications up to 1.5” w.c. and are not
adjustable. MR212 valves are factory set for applications
up to -1.5” w.c. and are eld adjustable for up to -3.5” w.c.

With the main valve closed an adjustable bypass provides
a minimum ring rate to the burner whenever the safety
shut-off valve(s) is open. This is low re to the heater.
Since the pressure regulator maintains a constant supply
pressure, the minimum ring rate is also held constant.
The MR212’s regulator is an integral component while a
seperate upstream pressure regulator is required for the
M411, M511, and M611.

As voltage is applied to the control’s solenoid, a mag­netic force is applied to the plunger. The plunger in turn
pushes down on the main diaphragm of the M411, M511,
and M611 valves or allows pressure to develop in the up­per chamber of the MR212 valve. These forces on the
main diaphragm are very similar to the spring loading of
a gas pressure regulator. When the force is sufcient to
overcome the counter spring the main valve will open and
gas will ow through the main valve in addition to ow­ing through the bypass. With sufcient voltage, the main
valve (modulator valve for the MR212) will fully open and
the pressure regulator will limit the burner pressure to the
desired amount, thus establishing a controlled maximum
high re condition.

We now have two extremes. The rst is low re with no
force on the plunger and ow through the bypass only.
The second is high re with sufcient force on the plunger
to fully open the valve (modulator valve for hte MR212),
with the gas pressure regulator controlling the maximum
ring pressure. Force on the plunger between these ex­tremes results in modulated gas ow. The voltage versus
outlet pressure curve, throughout the modulating range,
is fairly linear.

There are also applications where it is desirable to have
two seperate high re burner settings. Typical applications
would be a two speed fan operation or LP natural gas
change over. This is accomplished by adding an adjust­able resistance to the circuit, thereby limiting voltage to
the valve. Changing from one setting to another is done
by connecting a single pole single throw switch (customer
supplied) that when in the open position allows the out­let pressure to be adjusted up to 2” w.c. below normal
maximum high re. Negative pressure valves designed
for dual pressure settings are designated with a - 2 sufx

© 2008 Maxitrol Company, All Rights Reserved

2

(example: MR212D-2). Field conversion kits (KT/10542)
to modify single pressure valves are also available.

The working voltage to operate the modulating controls
can be supplied by the A1014, A1024, A1044, A1494 and
AD1094 Ampliers or the SC10 Signal Conditioner. (Re­fer to Bulletin SEL1444_CC_EN, SEL94_CC_EN, and
SC10C_MS_EN).

Valves designed for direct red applications (posi­tive pressure/push through) MR212D-1, MR212E-1,
MR212G-1, and MR212J-1.

The valve’s operating principles are identical to the nega­tive pressure MR212. The only difference is the valve
has been designed to operate on positive pressure (push
through) applications. Positive pressure valves designed
for dual pressure settings are designated with a - 3 sufx
(example: MR212D-3).

INDIRECT FIRED

MR410, MR510, and MR610

These valves use two springs in order to set the high and
low re settings. One spring (min.) surrounds the solenoid
and is always in contact with the diaphragm assembly.
The other spring (max.) is located above the plunger. With
zero voltage applied, the minimum and maximum spring’s
down force, along with plunger weight, pushes down on
the diaphragm thereby setting a regulated high re. A
seperate pressure regulator is not required. As voltage is
applied, the plunger pulls up sufciently until all plunger
weight and maximum spring force is removed. The pres­sure is now controlled with the minimum spring setting
giving a regulated low re condition. Force on the plunger
between the extremes results in modulated gas ow. The
voltage versus outlet pressure curve, throughout the mod­ulating range, is not linear.

These valves are driven with the A1010 or A1011 Amplier
or SC10 Signal Conditioners. (Refer to Bulletin SEL2030_
2131_CC_EN & SC10C_MS_EN)

Valves designed to operate on indirect red atmo­spheric burner applications M420, M520, M620.

These valves function in the same manner as the direct
red M valves. A pressure adjustment spring has been fac­tory set to obtain an outlet pressure slightly above atmo­spheric pressure (0.1” w.c.) with the bypass closed and
zero voltage being applied. The minimum ow rate is now
adjusted through the bypass.

NOTE: Minimum outlet pressure is always above 0.2” w.c.

- maximum outlet pressure is 7.0” w.c.

They can be driven by the A1094 and AD1094 Ampliers
or SC10 Signal Conditioners. (SEL94_CC_EN & SC10C_
MS_EN)

Valves designed to operate on indirect red atmo­spheric burner applications M451, M551, M651,
MR251D, MR251E, MR251G.

These valves function in the same manner as the direct
red M valves. Minimum input pressure is set using a mini­mum adjustment spring - the valves do not use a bypass.

‘H’ SUFFIX MODELS

Valves designed with wider modulation span for use

with LPG (liquid propane gas) and other applications

MR410H-1, MR510H-1, MR610H-1, M420H, M520H,
M620H.

Can be congured for indirect red atmospheric burner
applications, as well as those with direct red burners.

H-1 models are designed for applications with a total mod­ulation span greater than 7” w.c. Minimum outlet pressure
range of 1” to 2.8” w.c.

H models are designed for applications where outlet pres­sure is greater than 7” w.c. Minimum outlet pressure is
factory set to 1.75” w.c. - remaining set pressure is ob­tained through bypass.

The H models are capable of a total modulation span of
as much as 10” w.c. These models are not recommended
for applications with a total modulation span of less than
7” w.c. - the sensitivity of outlet pressure change relative
to voltage change could cause hunting to occur.

They are used in applications where the minimum input
pressure to burner is between 2.0” and 4.5” w.c. Maximum
obtainable outlet pressure is 7.0” w.c. above minimum in­put pressure.

The valves are driven by the A1094 and AD1094 Ampliers
or SC10 Signal Conditioners. (Refer to Bulletin SEL94_
CC_EN & SC10C_MS_EN)

© 2008 Maxitrol Company, All Rights Reserved

NOTE: Temperatures shown in text are for Maxitrol’s
Selectra® systems. Valves may be used for any

temperature range or application the user’s control­ler can handle. When using valves for other ranges,

a Maxitrol SC10 Signal Conditioner can be used in
conjunction with the valve. (Refer to Bulletin SC10C_
MS_EN)

3

SPECIFICATIONS

Vent:

Models M411, M511, M611, M420, M520, M620, M420H,
M520H, M620H, MR410H-1, MR510H-1, MR610H-1,
M551, M651 - vertical vent outlet 1/8” NPT - 12A06 in­stalled.

Certications:

M611, MR212D, E, & G with Series 14: CSA listed to certify
compliance with nationally published safety, construction,
and performance standards.

Models MR212 and MR251 - two vents located in upper
housing, both equipped with vent limiting means.

M411, M420, M420H, M451, M511, M520, M520H, M611,

M620, M620H, MR212D, E, G, & J with AD1094 controls:
CSA listed to certify compliance with nationally published

Ambient Limits:

safety, construction, and performance standards.

Operating ........................... -40º to 125ºF (-40º to 50ºC)

Non-operating .................... -50º to 185ºF (-45º to 85ºC)

MR410, MR410H-1, MR510, MR510H-1, MR610, and

MR610H-1: CSA certied to Z21.18 and CSA 6.3-M82.

Mounting:

Must be mounted in upright position in horizontal pipe
run, downstream of all other controls except high pres­sure cut-off switch if used. (See page 8)

Gases:

M611, MR212D, E, & G: UL recognized for compliance to

nationally published safety, construction, and performance

standards.

Natural, Manufactured, Mixed, Liqueed Petroleum and
Liqueed Petroleum Gas Air Mixture H, H-1 models for
use with Liqueed Petroleum and other applications.

design certied

Model Coil Resistance Ohms @ 68ºF Maximum Current Draw

MR410, MR410-1, M411, M420, M451, MR212, MR251 64 400 mA

MR510, MR510-1, M511, M520, M551 55 500 mA

MR610, MR610-1, M611, M620, M651 46 600 mA

MR410H, MR410H-1, M411H, M420H, MR212H 40 700 mA

MR510H, MR510H-1, M511H, M520H 33 850 mA

M610H, MR610H-1, M611H, M620H 29 1000 mA

© 2008 Maxitrol Company, All Rights Reserved

4

System

Used With

Output Control Means

Standard Factory Setting (if applicable)

SC10

Series 14,

24, 44, 94,

Low Fire: adjustable orice bypass

High Fire: upstream pressure regulator set-

ting less pressure drop

Note: 7” w.c. (17 mbar) max outlet pressure

Low Fire: adjustable orice bypass

SC10

Series 94,

High Fire: upstream pressure regulator set-

ting less pressure drop

Note: 7” w.c. (17 mbar) max outlet pressure

Note: H models: 11” w.c. (27 mbar) max

outlet pressure

SC10

Series 94,

Low Fire: spring adjustment

Std. Model: 1.2” - 2.5” w.c. (3-6.2 mbar)

-1 models: 2” - 4.5” w.c (5-11 mbar)

High Fire: upstream pressure regulator set-

ting less pressure drop

SC10

Series 94,

Low Fire: spring adjustment 2” - 4.5” w.c.

(5-11 mbar)

High FIre: maximum 7” w.c. (17 mbar) above

minimum setting

SC10

Series 14,

24, 44, 94,

Low re: adjustable orice bypass

High re: spring adjustment

High Fire Setting:

Std. model: 2 -5” w.c. (5-12.5 mbar)

reduced to 0-3” w.c. (0-7.5 mbar)

-2 model: 2” - 5” w.c. (5-12.5 mbar)

reduced to 0-3” w.c. (0-7.5 mbar)

Low re: spring adjustment

High re: spring adjustment

Std. model: 2” - 5” w.c. (5-12.5 mbar)

max-4” w.c. (10 mbar)

-1 model: min-1.5” w.c. (3.75 mbar)

21, 30, 31

Series 20,

max-4” w.c. (10 mbar)

H-1 model

min outlet pressure = 1.75” w.c. (4.4 mbar)

max outlet pressure = 111” w.c. (27 mbar)

Note: H-1 models: 7.5” to 12” w.c. max outlet

pressure

®

Exposure

Maximum

Emergency

Pressure

Upstream

CSA

Required

Regulator

Limits

Operating

Inlet Pressure

sure

Tested*

Inlet Pres-

Increase in volt-

2.5 psi
(170 mbar)

Yes

Upstream

lator setting

pressure regu-

1/2 psi

(34 mbar)

to increase in

outlet pressure

age corresponds

Increase in volt-

2.5 psi
(170 mbar)

Yes

Upstream

lator setting

pressure regu-

1/2 psi

(34 mbar)

to increase in

outlet pressure

age corresponds

2.5 psi
(170 mbar)

Yes

Upstream

lator setting

pressure regu-

1/2 psi

(34 mbar)

to increase in

Increase in volt-

outlet pressure

age corresponds

(860 mbar)

No 12.5 psi

5 psi

(340 mbar)

- -

CSA

to increase in

Increase in volt-

outlet pressure

age corresponds

Inlet

Rated^

Pressure

12.5 psi
(860 mbar)

No

5 psi

(340 mbar)

5 psi

(340 mbar)

to increase in

Increase in volt-

outlet pressure

age corresponds

2.5 psi
(170 mbar)

No

1 psi

(70 mbar)

1/2 psi

(34 mbar)

to increase in

outlet pressure

age corresponds

Decrease in volt-

Application Function

Max.

Current

Draw

(amps)

Model

Number

Pressure) Burners

Direct Fired (Negative

0.4

0.5

M411

M511

Atmospheric Burners

0.6

0.4

0.7

M611

M420

M420H

as LP applications)

H Models for higher

outlet pressures (such

0.5

0.6

1.0

0.85

M520

M620

M520H

M620H

M/MR SERIES APPLICATIONS TABLE

© 2008 Maxitrol Company, All Rights Reserved

- where higher outlet

Atmospheric Burners

pressures are needed

0.4

0.5

0.6

M451

M551

M651

- where higher outlet

Atmospheric Burners

pressures are needed

0.4

MR251E

MR251D

MR251G

5

Pressure) Burners

Direct Fired (Negative

0.4

MR212J

MR212E

MR212D

MR212G

Atmospheric Burners

0.4

MR410

outlet pressure (such

H-1 models for higher

as for LP applications)

0.7

0.5

0.6

1.0

0.85

MR510

MR410H-1

MR610

MR510H-1

MR610H-1

* Where no ANSI standard currently exists, Maxitrol Controls have been CSA tested for use as a component of Maxitrol Selectra

systems. ^CSA Rated Inlet Pressures are established by ANSI standard Z21.18, CSA 6.3, and CSA 6.5 where applicable.

DIMENSIONS

A

D

C

Figure 2 : MR410, 510, 610, MR410H-1, 510H-1,
610H-1, M451, 551, 651

A

D

A

D

B

Figure 3 : M411, 511, M420H, 520H, 620H, M420,

520, 620

A

D

B

C

CC

B

B

Figure 4 : M611

Figure 5 : MR212, MR251*
(*Same as MR212 except single by-pass)

Dimensions - in inches (millimeters)

Dimension are to be used only as an aid in designing clearance for the valves.
Actual production dimensions may vary somewhat from those shown.

Model Number Swing Radius

MR410. MR410H-1, M411,

M420, M420H, M451

MR510, MR510H-1, M511,

M520, M520H, M551

MR610, MR610H-1, M620,

M620H, M651

A B C D

3.1 (79) 3.9 (100) 2 (51) 2.5 (54) 0.9 (24)

4.3 (109) 5.3 (135) 3.25 (83) 3.4 (86) 1.2 (30)

5.7 (145) 7.1 (180) 3.9 (99) 4 (102) 1.5 (37)

Dimensions

M611 6.2 (158) 7.7 (196) 3.9 (99) 4 (102) 1.5 (37)

MR212D, MR251D 8.1 (206) 10.2 (259) 7 (178) 5.5 (140) 2.3 (59)

MR212E, MR251E 8.6 (218) 11.25 (286) 9.1 (232) 8 (203) 3 (76)

MR212G, MR251G 10.4 (264) 14.75 (375) 13.5 (343) 11.75 (298) 4.6 (118)

MR212J (Not Shown) -- 24 (610 21.5 (546) 13.9 (352) 5.9 (149)

© 2008 Maxitrol Company, All Rights Reserved

6

CAPACITIES

Capacity - ow rate expressed in CFH (m3/h) - 0.64 sp gr gas, Pressure drop expressed in inches w.c. (millibars)

Consult with Maxitrol Company, for ows in excess of those shown below.

Model Number and

Pipe Size

MR410

MR410H-1

M411

M420†
M420H
M451

MR510

MR510H-1

M511†

M520‡
M520H
M551

MR610

MR610H-1

M620†
M620H
M651

3/8X3/8

1/2X1/2

1/2X1/2

3/4X3/4

3/4X3/4

1X1

100

(2.83)

0.33

(0.82)

0.27

(0.67)

150

(4.25)

0.75

(1.88)

0.61

(1.53)

0.17
(.42)

0.12

(0.30)

200

(5.66)

0.30
(.75)

0.21

(0.52)

250

(7.1)

0.47

(1.18)

0.32

(0.80)

0.14
(.35)

0.12

(0.30)

300

(8.5)

0.67

(1.68)

0.47

(1.18)

0.20

(.50)

0.16

(0.40)

350

(9.9)

0.92

(2.30)

0.64

(1.60)

0.27

(.67)

0.22

(0.55)

400

(11.3)

0.83

(2.07)

0.36
(.90)

0.29

(0.72)

450

(12.7)

0.45

(1.13)

0.37

(0.92)

500

(14.2)

0.56

(1.40)

0.45

(1.13)

600

(17.0)

0.81

(2.03)

0.66

(1.65)

† or ‡ Models to which min. ow applies. (Minimum ow maximum calculated ΔP = 3.5” w.c. [single by-pass])

Model Number

and Pipe Size

3/4x3/4

M611*

1x1

100

(2.83)

0.02

(0.05)

0.02

(0.05)

150

(4.25)

0.06

(0.15)

0.05

(0.12)

200

(5.66)

0.09

(0.23)

0.07

(0.18)

300

(8.5)

0.20

(0.50)

0.16

(0.40)

400

(11.3)

0.36

(0.90)

0.29

(0.72)

500

(14.2)

0.56

(1.40)

0.46

(1.15)

600

(17.0)

0.81

(2.03)

0.66

(1.65)

700

(19.8)

1.10

(2.75)

0.90

(2.25)

800

(22.7)

1.45

(3.63)

1.18

(2.95)

900

(25.5)

1.83

(4.58)

1.50

(3.75)

700

(19.8)

0.90

(2.25)

1000

(28.3)

1.85

(4.63)

750

(21.2)

1.00

(2.50)

CSA

Listed

1000

Min. Flow

†5-90

(0.14-2.5)

†5-125

(0.14-3.5)

‡5-185

(0.14-5.2)

†10-330

(0.28-9.3)

Min. Flow

10-330

(0.28-9.3)

Model Number and

Pipe Size

1x1

MR212D*

MR251D

MR212E*

MR251E

MR212G*

MR251G

*U.L. recognized
**Pressure Drop gures derived from CSA Maximum Listed Capacities in far right column (not ow at column top).

Model Number

and Pipe Size

MR212J 4x4

1¼x1¼

1½x1½

1½x1½

2x2

2½x2½

3x3

1000

(28.3)

1.9

(4.75)

1.7

(4.25)

1.7

(4.25)

6000

(170)

1.9

(4.75)

1500

(42.5)

2.9

(7.25)

2.3

(5.75)

2.2

(5.50)

8000

(227)

2.1

(5.25)

2000

(56.5)

4.9

(12.25)

3.1

(7.75)

2.9

(7.25

1.9

(4.75)

1.9

(4.75)

10000

(283)

2.4

(6.00)

2500

(70.8)

6.2**

(15.50)

4.8

(12.00)

3.9

(9.75)

2.4

(6.00)

2.1

(5.25)

12000

(340)

2.7

(6.75)

3000

(85.0)

5.9**

(14.75)

5.4

(13.50)

2.9

(7.25)

2.4

(6.00)

14000

(397)

3.1

(7.75)

3500

(99.0)

3.5

(8.75)

2.7

(6.75)

1.9

(4.75)

16000

(397)

3.6

(9.00)

5000

(142)

6.0**

(15.00)

5.5

(13.75)

2.2

(5.50)

2.1

(5.25)

18000

(510)

4.5

(11.25)

6000

(170)

6.0**

(15.00)

2.6

(6.50)

2.3

(5.75)

20000

(566)

5.4

(13.50)

7000
(198)

3.0

(7.50)

2.6

(6.50)

22000

(623)

(16.50)

10000

(283)

6.1

(15.25)

4.6

(11.50)

6.6

24000

(680)

7.8

(19.50)

11000

(311)

5.6

(14.00)

27000

(765)

(24.75)

9.9

CSA

Listed

2250

2750

3000

4750

5250

10000

11000

(31.00)

Min. Flow
Min. Flow

Applies to MR212s

(0.71-8.5)

(0.71-8.5)

(1.4-12.7)

30000

(850)

12.4

only

25-300

25-300

50-450

Min. Flow

1-1000

(0.03-28.3)

© 2008 Maxitrol Company, All Rights Reserved

7

TYPICAL GAS TRAINS

Modulator (M) or Modulator-Regulator (MR) Valve: Mount in upright position in horizontal run of pipe, downstream of
other controls - a seperate gas pressure regulator must be used with any modulator (M) valve.

Figure 6 : M Valve: Regulator upstream of modulator valve

Figure 7 : MR Valve: Modulator-Regulator valve

INSTALLATION OF MR410, MR510, MR610 VALVE

Figure 8 : If diaphragm type automatic gas valve
is used with seperate regulator, install MR valve
downstream from diaphragm gas valve. Retain
regulator in manifold and adjust 2 or 3 turns to
compensate for pressure drop of MR valve.

Figure 9 : If full combination control is used, in­stall MR valve downstream. Adjust regulator in
combination control 2 or 3 turns to compensate
for pressure drop at MR valve.

Figure 10 : If solenoid type automatic gas valve
is used with seperate regulator, replace regula­tor with the MR valve.

MR Valve must be in upright position, in horizontal run of pipe only with pilot gas supply upstream.

MODIFICATIONS

Models having the letters B, H, M, R, or W, or a combina­tion of these sufx letters, indicates the design modication
described below:

B - both sides tted for low re adjustment.

H - capable of a total modulation span of as much as 10” w.c.

M - PL parallel thread conforms to ISO 7-1.

R - Right side outlet - low re by-pass adjustment on right side.

Available on models: M411, M511, M420, and M520.

W - Indicates covered wire terminal connections, same as M611.

Available on models: M411, M511, M420, M520, M620,
M451, M551, and M651.

Note: Models M411, M511, and M611 are available with 1/8”
NPT connection for reading outlet pressure. Not availabe on
“B” models connection is located on opposite side of by-pass
adjustment. (See Dimensions section of this bulletin)

Maxitrol Company
23555 Telegraph Rd., PO Box 2230
Southeld, MI 48037-2230

MMR_MT_EN_10.2008

8

www.maxitrol.com

© 2008 Maxitrol Company

All Rights Reserved