Hydrolevel 724 User Manual

724 Series

Low Water Cut-Off
Feeder Combination

for Steam Boilers

24 VAC Operating Voltage

WARNING: Power must be off during installation or servicing of the control. Only qualified personnel may install or service the
control in accordance with local codes and ordinances. Read instructions completely before proceeding. Caution – Disconnect power
supply before beginning installation to prevent electrical shock or equipment damage.

HOW TO INSTALL

1

No moving parts in water.
No floats to hang-up or foul.

Unique two probe design. Bouncing
water line wonʼt cause on-off burner
cycling or water valve slamming
noise.

Easy installation. Quick hook-up
fittings adapt control to all 8" to 14"
sight glasses.

Simple fast wiring. Can be used with
any standard automatic water feeder.

(2) 6" x 1/2" brass nipples



(1) 1/2" x 1/2" x 3/8" tee



(1) 1/2" x 1/2" x 1/2" tee



(1) 2" x 1/2" brass nipple



(1) 711C manifold casting



(1) 3/8" copper tube



(2) 3/8" compression fittings



(1) 3/4" nipple (not included)



(1) Blow down valve



(not included)

Remove gauge glass assembly and nipples replac­ing nipples with two 6" brass nipples provided.
Install 1/2" x 1/2" x 3/8" teeon top nipple.

2 34

Install 1/2" x 2" brass nippleand 1/2" x 1/2" x
1/2" teeto 1/2" threaded hole in casting.
Note: Casting is designed for either left or right
mounting on gauge glass. Be sure to plug hole on
opposite side.

Thread tee attached to casting into bottom 6" nip­ple. Tighten until casting is vertical.

Install compression fittingsinto casting and
top tee. Size copper tubingand tighten
between the two compression fittings.

5 67

Attach control to probes using No. 8-32 self tap­ping screws provided. Install blow down valve (by
others) in bottom 3/4" tapped hole. Be sure to
attach maintenance tag in prominent place near
valve.

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Reattach gauge glass cocks and gauge glass into
end of 1/2" tees. Pressure-trol can be threaded
into 1/8" threaded hole on top of casting. If pres­sure-trol is not used, plug 1/8" hole on top of
casting.

Attach blue probe lead wire to upper probe and
white probe lead wire to bottom probe with wing
nuts and lock washers provided.

WIRING METHOD A:









s





s

SAME POWER SOURCE FOR CONTROL AND BURNER CIRCUIT.

A1

must be supplied to terminals 1 and 2 for internal
operation of the control.

Install a jumper between terminal 2
and terminal P(1). Power from terminal
P(1) is supplied to terminal P(2) when water
reaches the upper probe. Power to terminal P(2)
is removed when water falls below the bottom
probe.

A3 A4

burner circuit in series with other limit controls.
Consult boiler manufacturer’s instructions for
proper terminal connections. NOTE: Control is
wired in series with and before other limits.

Feeder Connection: Connect feeder
common to terminal 1. Connect feeder
hot to terminal V. Whenever water falls below the
lower probe, power is supplied to the feeder ter­minal V. When water reaches the upper probe,
power to the feeder is removed.

Connect input voltage (24 VAC, 60HZ)

A1

to terminals 1 and 2. 24 VAC, 60HZ

Connect terminal 1 to burner circuit

A3

neutral. Connect terminal P(2) to

A2

A2

A4

WIRING METHOD B:

B1 B2

B3 B4

SEPARATE POWER SOURCE FOR CONTROL AND BURNER CIRCUIT.

Connect input voltage (24 VAC, 60HZ)

B1

must be supplied to terminals 1 and 2 for internal
operation of the control.

Connect hot lead from burner
control circuit to terminal P(1).
This terminal supplies power to terminal P(2) in
normal operating conditions when water is at the
probe. Connect neutral to burner circuit.
NOTE: Consult boiler manufacturer’s instructions
for proper terminal connections.

Consult boiler manufacturer’s instructions for
proper terminal connections. NOTE: Control is
wired in series with and before other limits.

Feeder Connection: Connect feeder
common to terminal 1. Connect
feeder hot to terminal V. Whenever water falls
below the lower probe, power is supplied to the
feeder terminal V. When water reaches the upper
probe, power to the feeder is removed.

to terminals 1 and 2. 24 VAC, 60HZ

Connect terminal P(2) to burner circuit

B3

in series with other limit controls.

B2

B4

NOTE: All schematic diagrams show all systems in
the off position. No power applied.