Xylem MM 201H User Manual

Series 67 and 767
Low Water Cut-Offs
For Steam Boilers

INSTRUCTION MANUAL

MM-201H

A

D

2

INST

ALLATION –

T

OOLS NEEDED:

One (1) tube cutter, one (1) pencil, one (1) flathead
screwdriver, one (1) adjustable wrench and two (2)
pipe wrenches.

The Series 67 and Series 767 low water cut-offs are
float-type boiler controls designed to interrupt current
to the burner whenever the water drops to the cut-off
level.

The Series 767 is identical to Series 67 in all
respects except one. The Series 767 is equipped with

a 2-1/2" (63.5mm) pipe tap opening in the body, and
does not require the quick hook-up fittings supplied
with the Series 67. The pipe tapping allows for a
direct connection to the side of the boiler.

Electrical Ratings

Pump Circuit Rating (Amperes)

V

oltage Full Load Locked Rotor Pilot Duty

125 VA at

120 or 240 VAC

For Series 67 - The elevation of the control (A)
is already determined by the location of the
gauge glass tappings (B,C) on the boiler. The
horizontal cast line (D) should be located at or
above the boiler manufacturer's minimum safe
water level (E).

For Series 767 - The elevation of the control (A)
is already determined by the location of the 2­1/2 (63.5mm) pipe tapping on the boiler. The
horizontal cast line (D) of the body (A) should
be located at or above the boiler manufacturer's
minimum safe water level.

STEP 1 - Determine the Ele

vation at Which the

Low Water Cut-Off Controller Must be Installed

C

A

E

B

D

IMPOR

TANT: Follow the boiler manufacturer's

instructions along with all applicable codes and
ordinances for piping, blow down valve and water
gauge glass installation.

OPERA

TION

Maxim

um Steam Pressure: 20 psi (1.4 kg/cm

2

)

Series 67

Series 767

Note: 11 MV is rated at 24 V

A @ 24 VAC to 120 VAC

120 VAC

240 VAC

7.4

3.7

44.4

22.2

3

a. Turn the boiler off.

b. Drain the water in the boiler to a level which

is below the lower gauge glass tapping (B)
of the control body (A). Allow the boiler to
cool to 80˚F (27˚C) and allow the pressure
to release to 0 psi (0 bar).

STEP 2 - Preparation

OFF

ON

AA

B

a. Using a pipe wrench, remove the float blocking

tube (F) from the new control and tighten a 2"
(13mm) NPT pipe plug (G) (provided) into the
tapping on the bottom of the control body (A).
Tighten the pipe plug to 31 ft•lb (42 N•m).

A

F

G

When using the tape sealant on the external threads of pipes or fittings, follow the manufacturers instructions. Use
sparingly and do not place on the first thread.

!

CAUTION

STEP 3 - Installing the New Low Water Cut-Off

b. Using a pipe wrench, install a 2" (13mm)

nipple (H) into the lower gauge glass tapping
(B) and pipe tee assembly (J). Tighten both
connections to 31 ft•lb (42 N•m).

J

B

H

c. Using an adjustable wrench, install a a"

(9.5mm) NPT compression fitting base (K)
to the upper tapping (L) in the control (A).
Tighten to 31 ft•lb (42 N•m).

A

L

K

N

M

d. Using a pipe wrench, install a 2" (13mm)

nipple (M) into the upper tapping (N).
Tighten to 31 ft•lb (42 N•m).

e. Using a pipe wrench, install the pipe tee (P)

(provided) onto the nipple (M) in the upper
tapping (N). Tighten to 31 ft•lb (42 N•m).

N

M

P

f. Using an adjustable wrench, install 1/2 (13mm) NPT

compression fitting base (U) into the upper tee (P).
Tighten to 31 ft•lb (42 N•m). Place the compression nut
(R) and compression ring (S) over the top of tubing (Q).
Insert tubing (Q) into compression base (U). Turn
compression nut (R) hand tight. DO NOT TIGHTEN.

IMPORTANT: Do not use tape or pipe
sealant on the compression fittings.

Q

U S R

P

4