MODELS 250/250WC
Pump Control
Low Water Cut-Off
Combination
Operating Voltage ................. 120VAC
Max. Steam Pressure ............ 250PSI
Burner Relay ............. 10 FLA, 60 LRA
Pump Relay ................ 10 FLA, 60LRA
Alarm Relay ................ 10FLA, 60LRA
Power Consumption ................ 13 VA
The series 250 control requires regular maintenance for safe operation. Before installing
please read and understand the maintenance procedures listed on page 7 of this manual as
well as any required maintenance procedures listed in your boiler manufacturer’s instructions.
Electrical shock hazard. To prevent electrical shock, dea th or equipment damage, disconnect power supply before installing
or servicing control. Only qualified personnel may install or service this control in accordance with local codes and ordinances.
Read instructions completely before proceeding.
Frozen pipes/water damage. Central heating systems are prone to shut down as a result of power or fuel outages, safety
related fault conditions or equipment failure. Installation of freeze protection monitoring or other precautions is recommended for
unattended dwellings in climates subject to sustain below-freezing temperatures.
Disconnect power supply before beginning installation to prevent electrical shock or equipment damage.
This low water cut-off must be installed in series with all other limit and operating controls installed on the boiler. After installation,
check for proper operation of all of the limit and operating controls, before leaving the site.
To prevent serious personal injury from steam and hot water make sure there is a discharge line from the blow-down valve to a
proper place of disposal.
To prevent a fire, do not use this low water cut-off to switch currents over 7.4A, 1/3 HP at 120 VAC or 3.7A, 1/3 HP at 240 VAC,
unless a starter or relay is used in conjunction with it.
Always install a new control on a new boiler system. Never use a control that has already been used on a previous appliance.
Failure to follow this warning could cause property damage, personal injury or death.
1
Read and understand these instructions completely before installing or servicing this control. Save these instructions for
future reference.
Only qualified personnel may install or service the control in accordance with local codes and ordinances.
Secondary (redundant) Low Water Cut-Off controls must be installed on all steam commercial boilers. At least two con-
trols must be connected in series with the burner control circuit to provide redundant protection in the event the boiler
experiences a low water condition.
NOTICE
PLEASE READ BELOW BEFORE INSTALLING
• No moving parts to stick, wear or hang-up
• No replacement or rebuilding of floats or mechanical parts
• Reliable electronic design
• Made in the USA.
MODEL 250 MODEL 250WC
WARNING
2
INSTALLATION: MOUNTING LOCATION
INSTALLATION: MOUNTING
Install the Safgard 250 in a 1" equalizing
line equipped with a blow-down valve
meeting applicable state and local codes.
The control should be located so that the
“LOW WATER CUT-OFF LEVEL” marked
on the control casing is at least 1/2"
above the lowest permissable water level
as specified by the boiler manufacturer.
Any model 250 should act as
the primary Low Water Cut-Off ONLY. It
should not be used as a secondary Low
Water Cut-Off.
Model 250 diagram on page 5. Model 250WC diagram on page 6.
Mount the Low Water Cut-Off and Pump Controller
See Figure 1 below. Mount and pipe the Low Water Cut Off Manifold on a vertical equalizing pipe at the required
elevation level determined in mounting location section above. Then, install a fully ported blow-down valve (and
discharge line) directly below the lower cross of the water equalizing pipe.
For best results, we recommend a dual valve blow-down system for the 250 Series Control.
Gauge Glass
Model 250WC is designed to have a gauge glass (not included) on the Low Water Cut Off Manifold (see diagram on
page 6 for mounting location).
VERTICAL
EQUALIZING
PIPE
250 LWCO
WATER
EQUALIZING
PIPE
UPPER BLOW-DOWN
VALVE (recommended)
LOWER BLOW-DOWN
VALVE
250 LWCO 250WC LWCO
LOW WATER CUT-OFF
LEVEL INDICATOR
LOW WATER CUT-OFF
LEVEL INDICATOR
Gauge Glass and relevant mounting
hardware not included (see Gauge
Glass section under Mounting below)
Figure 1 Control mounting
3
INSTALLATION: WIRING
MODEL 250 AND 250WC LADDER WIRING DIAGRAM
DANGER The Safgard 250 is intended as a pilot duty control only and must be installed with a relay between it and both the
condensate pump and burner circuit. Direct wiring of the control to either the burner circuit or condensate pump
can result in failure of the control.
GH
ALWCO
ALARM
RY2 N.C.
120VAC
HOT
TOP
MIDDLE
RY1
N.O.
INTERNAL
TRANSFORMER
BOILER
GROUND
BOTTOM
120VAC
NEUTRAL
FIELD
WIRING
RY1 N.C.
RY2 N.O.
FEED
PUMP
LIMITS BURNER
P P
PROBES
INTERNAL
WIRING
V
FE
RY1
RY2
4
PROBE DATA
TYPICAL APPLICATIONS
PROBE TEST PRESSURE 1000PSI
1 Safgard 250 Pump Controller/LWCO combination
2 Safgard 270 High Water Limit/Alarm
3 Safgard 550 or 750 as Secondary LWCO
4 45-715 Feed Valve Assembly
5 Safgard 727 Tank Control
123
4
5
5
DIMENSIONS and CONTROL LAYOUT — Model 250 LWCO
MAXIMUM STEAM PRESSURE 250 PSI
6
DIMENSIONS and CONTROL LAYOUT — Model 250WC LWCO
7
REQUIRED BLOW-DOWN PROCEDURE
SERVICE / MAINTENANCE
In addition to the blow-down and test procedure above, the probes must be removed and examined annually. The
probes can usually be cleaned with a soft cloth although they are rugged enough to be cleaned with steel wool or a
scouring pad if a more crystalline or solid buildup is present. A more frequent examination interval may be necessary
based on the condition of the unit at time of inspection. Replacement may be necessary.
•
Probes should be inspected and cleaned more often on systems with high make-up water or untreated boiler water.
• After each scheduled or unplanned outage, the low water cut-offs should be dismantled, inspected, cleaned and
checked for proper performance.
Be sure to consult the boiler manufacturer’s manual for chemical water treatment and PH level
recommendations.
NOTICE – PLEASE READ The Series 250 control requires regular maintenance for safe
operation. Please read and understand the maintenance procedures listed in this manual as
well as any required maintenance procedures listed in the boiler manufacturer’s instructions.
WARNING To prevent serious personal injury from steam and hot water, make sure there is a discharge line from the
blow-down valve to a proper place of disposal. Failure to follow this caution could result in personal injury.
The 250 Series Control requires regular maintenance (including blowdown) to ensure continued safe operation.
During normal boiler function, sediment may accumulate in the low water cut-off’s probe housing. If left unchecked,
this sediment can build up, trap water in the probe housing, and prevent the control from detecting a low water con-
dition in the boiler. A regular blow down of the control is required for proper operation.
Blow Down Schedule
To flush the sediment from the chamber, the control must be blown down in accordance with the following schedule:
• Daily if operating pressure is above 15PSI
• Weekly if operating pressure is below 15psi
Before Blow Down
Blow-down the 250 Series Control when the burner is on and the water level is at its normal operating level [between
middle (PUMP ON) probe and upper (PUMP OFF) probe, see diagrams on pages 5 and 6]. Confirm water is visible
in the site glass. If not visible, shut the burner off, allow the boiler to fully cool, then add water until visible in the site
glass. Once water is visible, bring the boiler back up to temperature.
For best results, we recommend a dual valve blow-down system for the 250 Series Control.
Blow Down Instructions
1 Open the upper valve
2 SLOWLY open the lower valve
3 Drain the water until the water level falls below the lowest probe (LOW
WATER CUT OFF) on the control
a. As water in the sight glass lowers, the pump will turn on (water in site
glass falls below the middle probe) and the burner will turn off (water
in site glass falls below the lowest probe)
4 Confirm that, once water falls below the lowest probe, the water is
running clean – free of major sediment
5 Once water runs clean, SLOWLY close the lower valve
6 Close the upper valve
7 At this step your pump should be on, raising the water in the site glass.
As the water rises above the lowest probe, your burner will turn on
NOTE: IF THE CONTROL DOES NOT OPERATE AS DESCRIBED IN
STEP 3a, IMMEDIATELY CLOSE ALL VALVES AND SHUT DOWN
THE BOILER. INSPECTION OF THE CONTROL MAY BE NECESSARY TO DETERMINE WHY THE CONTROL
WASN’T WORKING PROPERLY. AFTER THE PROBLEM HAS BEEN IDENTIFIED AND FIXED, RESET YOUR
CONTROL AND REPEAT INSTRUCTIONS ABOVE.
VERTICAL
EQUALIZING
PIPE
250 LWCO
WATER
EQUALIZING
PIPE
UPPER BLOW-DOWN
VALVE (recommended)
LOWER BLOW-DOWN
VALVE
126 Bailey Road • North Haven, CT 06473 • (203) 776-0473 • FAX (203) 764-1711 • www.hydrolevel.com
LIMITED MANUFACTURER’S WARRANTY
We warrant products manufactured by Hydrolevel Company to be free from defects
in material and workmanship for a period of two years from the date of manufacture
or one year from the date of installation, whichever occurs first. In the event of any
claim under this warranty or otherwise with respect to our products which is made
within such period, we will, at our option, repair or replace such products or refund
the purchase price paid to us by you for such products. In no event shall Hydrolevel
Company be liable for any other loss or damage, whether direct, indirect, incidental
or consequential. This warranty is your EXCLUSIVE remedy and shall be IN PLACE OF
any other warranty or guarantee, express or implied, including, without limitation, any
warranty of MERCHANTABILITY or fitness for a particular purpose. This warranty may
not be assigned or transferred and any unauthorized transfer or assignment thereof
shall be void and of no force or effect.
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8
NOTES
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