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