Xylem McDonnell & Miller 1575 Series User manual

INSTRUCTION MANUAL
MM-286D
212634
• Before using this product read and understand instructions.
• Save these instructions for future reference.
• Allworkmustbeperformedbyqualiedpersonneltrainedintheproperapplication,
installation,andmaintenanceofplumbing,steam,andelectricaland/orsystemsin
accordance with all applicable codes and ordinances.
• Topreventseriousburns,theboilermustbecooledto80°F(27°C)andthepressuremustbe
0psi(0bar)beforeservicing.
• Topreventelectricalshock,turnofftheelectricalpowerbeforemakingelectricalconnections.
• 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.
• Werecommendthatsecondary(redundant)LowWatercut-offcontrolsbeinstalledonallsteam
boilerswithheatinputgreaterthan400,000BTU/houroroperatingabove15psiofsteam
pressure. At least two controls should be connected in series with the burner control circuit to
provide safety redundancy protection should the boiler experience a low water condition.
Moreover,ateachannualoutage,thelowwatercut-offsshouldbedismantled,inspected,
cleaned,andcheckedforpropercalibrationandperformance.
• Topreventseriouspersonalinjuryfromsteamblowdown,connectadrainpipetothecontrol
opening to avoid exposure to steam discharge.
• Topreventare,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.
• ThisproductcanexposeyoutochemicalsincludingLead,whichisknowntotheStateof
Californiatocausecancerandbirthdefectsorotherreproductiveharm.Formore
informationgoto:www.P65Warnings.ca.gov.

2
Electronic Control Unit
Burner Relay Time Delay
The field-adjustable time delay (DOB) helps to
p r event nuisance bu r ner shut-dow n . The number
of seconds water needs to be off the longest probe
b e fore the bu r ner will shut down can be set
b e t w een 0 and 60 seconds.
Redundant Low Water Cut-Off
When the boiler water drops below the middle
p r o b e, a 3 minute timing circuit will be activa t e d . I f
water does not return to the middle probe within
three minu t e s, the bu rner relay will shut dow n . T h e
Red LED will flash once eve r y second if this
condition occurs.
• Automatic Reset units will automatically reset
when the water level is restored to the middle probe.
N OT E : The timing circuit will automatically reset
if the water level returns to the middle probe within
3 minu t e s.
Redundant Pump Off
The pump relay will be activated, turning the pump
on after water drops below the middle probe. If the
water level is not restored to the top probe within 3
m i nutes the pump relay will be deactivated, shutting
off the pump. After the pump relay is deactiva t e d ,
n o r mal operation is resumed. Water must again
drop off the middle probe to activate the pump
r e l ay. There is no LED signal for this occura n c e.
A d j u s t a ble Pump Diffe r e n t i a l s
The water level positions for turning the pump on
and off and obtaining the needed pump diffe r e n t i a l s
are changed by cutting the length of the middle and
s h o r test probes.
Previous controls should never be installed on a new system. Always install new
•
controls on a new boiler or system.
CAUTION:
A more frequent replacement interval may be necessary based on the condition of
the unit at time of inspection. McDonnell Miller s warranty is one (1) year from date
of installation or two (2) years from the date of manufacture.

Failure to follow this warning could cause property damage, personal inj ury or death.
•
&'

3
SPECIFICATIONS
M a x i mum Pressure: 150 psi (10.5 kg/cm2)
Burner Delay (DOB): 0 to 60 seconds (Field Adjustabl e )
Ambient Te m p : 120˚F Max.
N OT E : The circuit board is protected with a sensor which will
shut down the unit if the temperature at the board ex c e e d s
176˚F (80˚C). The board will reset when the temperature at
the board drops below 167˚F (75˚C).
ELECTRICAL RATINGS & SWITCH RATINGS
Supply Probe Full Load (Amps) Locked Rotor (Amps) Pilot Duty (VA) Motor (HP)
Voltage Voltage NO (NC), VAC NO (NC), VAC NO (NC), VAC NO (NC), VAC
120 VAC 5 VAC 16 (5.8), 120 96 (34.8), 120 470 (290), 120 1 (1/4), 120
50/60 HZ maximum 8 (2.9), 240 48 (17.4), 240 470 (290), 240 1 (1/4), 240
M a x i mum System Water Te m p e r a t u r e : 406˚F (208˚C)
M a x i mum System Water Pressure: 250 psi (17.6 kg/cm2)
M a x i mum System Steam Pressure: 250 psi (17.6 kg/cm2)
All probes in the Series 1575 units are sent from the factory pre-cut to
9" length (229mm). Any of the probes can be used as the low water
cut-off level probe.The 9" length positions the probe at the low water
cut-off cast-in line on the chamber body.The remaining probes can be
‘cut to length’ using a metal cutting saw to achieve desired pump control
(pump on/pump off) and pump differential levels. Approximately 1 inch
of the metal probe rod should be exposed below the PTFE coating.
4-3/16"
(106.4)
4-3/8"
(111)
AB
CD
2-1/2"
(63.5)
3-1/4"
(82.5)
3-1/4"
(82.5)
3-1/8"
(79.4)
1" NPT
11-1/2"
(292)
18-5/8"
(473)
1/2" NPT
1/2" NPT
1/2" NPT
CONDUIT
CONNECTION 1"
NPT
1" NPT
1/2" NPT
ELECTRODE
PRE-CUT
9" PROBE ROD
CUT AS
NEEDED

4
When the water level in the boiler drops below the
middle probe, the circuit is broken which will
a c t i vate the pump relay, turning the pump on. W h e n
the water level rises above the shortest probe, the
circuit is made and the pump relay is deactiva t e d ,
t u r ning the pump off.
When the water level in the boiler drops below the
longest probe, the circuit is broken which will
d e a c t i vate the bu rner relay, turning the bu rner off.
When the water level is restored to the middle
p r o b e, the bu r ner relay will be activated (bu rner on)
for auto reset controls only.
SWITCH SETTINGS:
Chamber
STEP 1 - Installation
TOOLS NEEDED:
One (1) pipe wrench, one (1) flathead screwdriver and/or 11/32" nut driver,
one (1) metal-cutting saw, one (1) 9/16" socket or wrench and pipe sealing compound.
If the control will be the primary low water fuel
cut-off, size the steam (top) and water (bottom)
equalizing pipe lengths to the chamber so that the
cut-off level mark is 11/2" (38mm) below the
boiler’s normal water level, but not lower than
the lowest safe permissible water level, as
determined by the boiler manufacturer.
OR
If the control will be the secondary low water
fuel cut-off, s i z e the steam (top) and water (bottom)
equalizing pipe lengths to the chamber so that the
cut-off level mark is at or abov e the lowest safe
p e r m i s s i bl e water level, as determined by the
boiler manufacturer.
• Mount C o n t rol Box in a suitable location near
the boiler’s main electrical panel.
• Install electrical conduit between electrical
enclosure of the P robe Chamber and
C o n t rol Box .
• Pull four (4) wires through conduit.
Boiler sight glass must be visible from location of
Control Box and must be within 25 feet of Control
Box.
NOTE
R e fer to and fo l l ow local codes and standard s
when selecting conduit and electrical fittings.
Wires from Electrical Enclosure of the Pro b e
Chamber to Control Box must be in their own
c o n d u i t . If they are run in conduit with other wires,
there may be interference that can affect the
performance of the control.
NOTE
Wire must be 18 AWG stranded with glass braided
silicone jacket (UL 3071) suitable for high temper-
ature (200˚C) service.
NOTE
SPECIFICATIONS (cont.)

6
Circuit Board Layout
STEP 2 - Electrical Wiring
• To prevent electrical shock , turn off the electrical power before making electrical connections.
•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.
•Boiler manufacturer schematics should always be followed. In the event that the boiler manufacturer’s
schematic does not exist, or is not available from the boiler manufacturer, refer to the schematics provided
in this document.
Failure to follow this warning could cause electrical shock, an explosion and/or a fire,which could result in
property damage, personal injury or death.
WARNING
C o ver Removal and Installation Pro c e d u r e
a . To remove cove r, use a flathead screw d ri ver to
loosen screws and remove the cover (K).
b . To reconnect cove r, slide over bra ckets and tighten
s c r e ws using a flathead screw d ri ve r.
c . Following the appropriate wiring diagram (refer to
page 7) based on your application requirements,
and using BX armored cable or Thinwall electrical
metal tubing connector fittings, make electrical
connections to the junction box (L).
I M P O RTA N T:There must be a minimum space
of 2 " (13mm) between connector fittings and
electrical live metal parts.
K
L
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
60
30
Secs.
0 60
30
Secs.
0
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
060
30
Secs.
0
Probe Connections
Bottom
Red
Middle
Yellow
Top
Blue
0-60 Second Adjustable
Burner Off Delay
110 Volt Input
from Boiler
Circuit Manual Reset
(If applicable)
Low Water
LED
Red
Power
LED
Green
Test
Switch
Burner
Te r minals
Pump
Te r minals
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
Probe LED's

7
• Connect wire “ a ” from power supply to
t e rminal “ H ” .
• Connect wire “ b ” from neutral supply to
t e rminal “ N ” .
• Connect wire “ c ” from pump control circuit
to terminal “ P N O ” .
• Connect wire “ d ” from pump control circuit
to terminal “ P C O M ” .
• Connect wire “ e ” from bu rner control
circuit to terminal “ B N O ” .
• Connect wire “ f ” from alarm control circuit
to terminal “ B N C ” .
• Connect wire “ g ” from bu rner or alarm
control circuit to terminal “ B C O M ” .
WIRING DIAGRAMS
Low Water Cut-Off,Alarm and Pump Up Control
• Connect wire “ a ” from power supply to
t e rminal “ H ” .
• Connect wire “ b ” from neutral supply to
t e rminal “ N ” .
• Connect wire “ c ” from pump #1 control
circuit to terminal “ P N O ” .
• Connect wire “ d ” from pump #1 control
circuit to terminal “ P C O M ” .
• Connect wire “ e ” from pump #2 control
circuit to terminal “ B N C ” .
• Connect wire “ f ” from pump #2 control
circuit to terminal “ B C O M ” .
Dual Pump Control
• Connect wire “ a ” from power supply to
t e r minal “ H ” .
• Connect wire “ b ” from neutral supply to
t e r minal “ N ” .
• Connect wire “ c ” from va l ve control circuit
to terminal “ P N O ” .
• Connect wire “ d ” from va l ve control circuit
to terminal “ P C O M ” .
• Connect wire “ e ” from bu rner control
circuit to terminal “ B N O ” .
• Connect wire “ f ” from alarm control circuit
to terminal “ B N C ” .
• Connect wire “ g ” from bu rner or alarm
control circuit to terminal “ B C O M ” .
Motorized Valve and Low Water Cut-Off
FROM BURNER OR ALARM
CONTROL CIRCUIT
TO ALARM
CONTROL CIRCUIT
TO BURNER
CONTROL CIRCUIT
FROM PUMP UP
CONTROL CIRCUIT
TO PUMP UP
CONTROL CIRCUIT
NEUTRAL
HOT
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
g
f
e
d
c
b
a
FROM PUMP #1
CONTROL CIRCUIT
FROM PUMP #2
CONTROL CIRCUIT
TO PUMP #2
CONTROL CIRCUIT
TO PUMP #1
CONTROL CIRCUIT
NEUTRAL
HOT
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
f
e
d
c
b
a
FROM VALVE
CONTROL CIRCUIT
TO VALVE
CONTROL CIRCUIT
NEUTRAL
HOT
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
d
c
b
a
FROM BURNER OR ALARM
CONTROL CIRCUIT
TO ALARM
CONTROL CIRCUIT
TO BURNER
CONTROL CIRCUIT
g
f
e

8
STEP 3 - Testing
Procedure
Turn on power to the boiler and pump circuits.With the boiler empty,
the control will be activated (Green LED On) and the pump should turn
on. The burner should stay off (Red LED On).
NOTE: If Green and Red LED’s flash alternately, the probes are out of
sequence, indicating they are not working correctly. Turn off power and
check probe wires for proper connection.
•Green light on: Unit has power
•Red light on: Boiler water dropped below the longest probe for longer than the adjustable time delay
setting. The burner has shut down.
•Red light flashing every second: Boiler water was below the middle probe for more than three
minutes and the burner has shut down.
•Auto reset units will automatically reset when the boiler water returns to the middle probe.
•Red light and green light flashing alternately every 1/2 second. Probes are out of sequence.
Unit has shut down. Unit will automatically reset when condition has cleared or been corrected.
•Red light and green light flashing simultaneously every 1/2 second: The PCB is too hot and the unit
has shut down. The unit will automatically restart when the PCB has cooled sufficiently.
•When using the “TEST” button, the green light will flash once per second during the time delay interval.
The time delay setting can be determined by counting the number of flashes.
Green Light – Shows status of shortest probe
Yellow Light – Shows status of middle probe
Red Light – Shows status of longest probe
•If the light is on, the probe is in water and probe resistance is well below the threshold.
•If the light is flashing every 1/2 second, the probe is in water, but probe resistance is near (just below)
the threshold.
•If the light is flashing every 2 seconds, the probe is out of water, but probe resistance is near (just above)
the threshold.
•If the light is off, the probe is out of water and probe resistance is well above the threshold.
I M P O RTA N T:Follow the boiler manufacturer’s start-up and operating instructions along with all applicable
codes and ordinances.
If the burner comes on, i m m e d i a t e ly turn the boiler off and make the
n e c e s s a ry corrections.
Failure to follow this warning could cause an explosion or fire and
result in property damage, personal injury or death.
WARNING
Exterior Lights
Interior Lights
OFF
ON

Adjusting Burner Delay (DOB)
The boiler should begin to fill with wa t e r.
N OT E : If water does not start filling the boiler,
immediately turn off the the boiler and make
the necessary corrections.
For Automatic Reset Models:
When the water level reaches the level of the
middle probe, the burner circuit should be acti-
vated and the Red LED should turn off. (Pump
#2 should turn off with Dual Pump Applications).
When the water level rises to the level of the top
p r o b e, the pump relay will be de-activa t e d .
Depending on the application, this will either turn
off the pump or close a va l ve.
The number of seconds that water must be off the
s h o r test probe before the bu rner will turn off is
a d j u s t a ble from 0 to 60 seconds. The unit is fa c t o r y
set at 0 seconds. To adjust, turn the adjusting screw
c l o ckwise using a small flatblade screw d r i ver to the
d e l ay time desired.
Fo l l owthe bl ow down procedure found on page 11
to ve r ify opera t i o n .
I N S TA L L ATION COMPLETE
If the time delay on the primary control set is too long,
the manual reset secondary LWCO may turn off the
boiler before the primary control turns off the boiler.
If this occurs, shorten the time delay by turning the
adjustment screw counter- c l o c kwise from the new setting.
NOTE
9
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
60
30
Secs.
0 60
30
Secs.
0
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
060
30
Secs.
0
Probe Connections
Bottom
Red
Middle
Yellow
Top
Blue
0-60 Second Adjustable
Burner Off Delay
110 Volt Input
from Boiler
Circuit Manual Reset
(If applicable)
Low Water
LED
Red
Power
LED
Green
Test
Switch
Burner
Te r minals
Pump
Te r minals
BCOM
BNC
BNO
PCOM
PNC
PNO
N
H
Probe LED's

Green LED does not turn on.
•There may be no power to the unit. Check wiring
connected to ‘H’ and ‘N’ terminals on circuit board.
Verify that the control is being powered when the
boiler power is turned on.
Red & Green LEDs flash alternately every
1/2 second.
•The probes are out of sequence. Check probe
wires and connections.
Red & Green LEDs flash simultaneously every
1/2 second.
•The temperature at the circuit board is higher than
170˚F. Removing the control box cover may cool
the control enough for it to operate.If the control
works with the cover removed, the control box
should then be mounted remotely.
Pump does not turn off when water level is above
shortest probe.
•The probes may be fouled with dirt, scale or rust.
Remove head assembly to inspect probes.
•The wiring connections for the pump may not be
connected properly. Check wiring at terminals.
Pump does not turn on when water level is below
the middle probe.
•The probes may be fouled with dirt, scale or rust.
Remove and inspect probes.
•The wiring connections for the pump may not be
connected properly. Check wiring at terminals.
Burner does not turn off when water level is
below longest probe.
•The probes may be fouled with dirt, scale or rust.
Remove and inspect probes.
•The wiring connections for the burner may not be
connected properly. Check wiring at terminals.
• Make sure the time delay is not causing delay of
burner off.
The 1575 control does not turn off the burner
before the secondary (manual reset LWCO) turns
off the burner.
•The burner off time delay (DOB) may be set for too
long of a delay.
During operation, the burner does not turn off
when the water level is below the longest probe.
•The burner off time delay (DOB) may be set for too
long of a delay.
•The boiler water may be priming or foaming. Clean
boiler water and/or consult with chemical treatment
specialist.
During operation, the burner turns off even when
the pump has turned on or the motorized valve
has opened.
•Pump capacity may not be sufficient or there may
be restrictions in the feedwater piping. Check pump
capacity and piping.
•The motorized valve stroke-to-open time may be
too long. Check valve motor timing.
Troubleshooting
10