HydroStat 3250-Plus User manual

1
83 Water Street • New Haven, CT 06511 • Phone [phone] • FAX [phone] • www.hydrolevel.com
MODEL 3250-Plus
Temp Limi / LWCO Con rol
wi h Thermal Targe ing™
for Wa er Boilers
120 VAC Operating Voltage
PATENT NO. 7,891,572
WARNING E ectrica shock hazard. To prevent electrical shock, death 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.
CAUTION To prevent serious
burns, boiler
should be thoroughly cooled before installing or
servicing control.
WARNING 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.
Three Function
Design
Temperature Limit Control
Designed for cold start and tankless
coil boilers.
Low Water Cut-Off
Provides protection against potentially
dangerous low water conditions
when installed with the ydrolevel
Electro-Well™ (see page 2 for details).
Boiler Reset Control
•Thermal Targeting – On-board micro-
processor adjusts boiler temperature
based on heating demand.
•Outdoor Reset Ready – Compatible with
ydrolevel OS-100 Outdoor Sensor Kit
(sold separately) for outdoor reset and
warm weather shut-down functionality.
INSTALLATION INSTRUCTIONS
and OPERATING MANUAL
• Saves Fuel – Features Thermal Targeting™ technology and
Thermal Pre-Purge capability
• Outdoor Reset Ready – Provides Outdoor Reset and Warm Weather
Shut-Down capability with the addition of ydrolevel OS-100 Outdoor
Sensor Kit (sold separately)
• Universal Design – Replaces common cold-start and triple-action
Aquastats*
• Operating Indicators – LEDs, Dynamic Display and Test Button provide
continual and on-demand status checks
• Prioritizes Domestic Hot Water – Gives priority to low limit setting or to
calls from indirect water heater
• Reduces Condensation – olds circulator off until boiler reaches 125°F
•*Aquastat is a registered trademark of Honeywell International, Inc.
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2
MOUNTING THE CONTROL
STEP 1
Two mounting positions
are available on the back of the control
(Fig. 1). Select which of the two positions
(2 knockouts) is best for the location of
the control. Remove the knockout.
STEP 2 Place control on the well.
While holding box against well nut,
tighten well clamp screw. (Fig. 2)
BACK OF
FUEL SMART YDROSTAT BOX
FIG. 1 FIG. 3FIG. 2
OTE: In the case of space restrictions, the Fuel Smart ydroStat control may be mounted in a horizontal orientation without any
loss of function. ydrolevel recommends vertical mounting, when possible, for proper orientation of LED display.
REMOTE MOU TI G KITS are available separately for mounting the Fuel Smart ydroStat control box in a remote location.
Each kit includes mounting hardware and a remote sensor. See page 16 for kit options.
STEP 3 Insert sensor ALL T E
WAY into well through the knockout (A
or B) you have chosen. (Fig. 3)
IMPORTANT Make sure that the immersion we or E ectro-We ™ is insta ed in the boi er manufacturer’s designated
temperature imit contro tapping.
NNOOTTEE:: If installing an Electro-Well™, pipe sealing compound should be used. Tef on tape is not recommended.
IMMERSION WELLS
When installed on an Electro-Well™ (sold separately), the Low Water Cut-Off
function is automatically activated. Heat transfer grease should not be used.
NOTE: For proper operation, there must be 1/2" clearance between the cop-
per well tube and any furnace within the boiler.
See Electro-Well™ models on page 15.
When installing on a standard immersion well, the LWCO f nction sho ld
be t rned off (see page 10 for instructions). A buildup of heat transfer
grease or other coatings in older wells can interfere with continuity between
the sensor and the well causing a false low water shutdown. Turning off the
LWCO function will prevent this from occurring.
Fuel Smart ydroStat can be installed on a ydrolevel Electro-Well™ or on an existing immersion well already in the boiler.
IMPORTA T: The control will only provide low water cut-off protection when installed on an Electro-Well™.
Installing HydroStat
with Hydrolevel Electro-Well™
Installing HydroStat
with Standard Immersion Well
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WIRING
3
STEP 1 Connect 120 VAC ot to terminal L1. Connect
120 VAC Neutral to terminal L2. Disconnect means and
overload protection as required (provided by others).
Select the Diagram that
Matches your System Con iguration
on Pages 4, 5 or 6
STEP 2 Connect the burner circuit to B1-B2.
(B2 is neutral.)
WARNING E ectrica shock hazard. To prevent electrical shock, death or equipment damage, disconnect power supply before
installing or servicing this control.
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4
Connect thermostat or end switch from zone relay or multi-zone
panel to T-T. Connect circulator to C2-C1. Connect end switch
from indirect zone relay to ZC-ZR. Move Zone/Indirect Switch
down to I.
SINGLE CIRCULATOR MULTIPLE CIRCULATORS
Connect end switch from heating circulator relays or multi-zone
panel to T-T. Connect end switch from indirect circulator relay to
ZC-ZR. Move Zone/Indirect Switch to I.
IMPORTA T: When installing with an indirect water heater, the Zone/Indirect Switch must be set in the Iposition. When set in the Iposition, calls to ZC-ZR will
bypass the Thermal Targeting feature and allow the boiler to fire to the high limit setting to heat the indirect tank. The indirect signal must be separate from all
heating zone signals. If you choose not to separate the indirect signal from the heating zones, the Economy Feature should be turned OFF to ensure that the
boiler supplies adequate temperature to heat the indirect tank (see page 7).
ZONE/
INDIRECT
SWITCH
POSITION
ZONE/
INDIRECT
SWITCH
POSITION
Connect thermostat or end switch from zone relay or multi-
zone panel to T-T. Connect circulator to C2-C1. Move
Zone/Indirect Switch up to Z.
Connect end switch from circulator relay or multi-zone panel to
ZC-ZR. Move Zone/Indirect Switch up to Z.
STEP 3A: HEATING ONLY – No Indirect Water Heater
STEP 3B: HEATING and Indirect Water Heater
SINGLE CIRCULATOR MULTIPLE CIRCULATORS
ZONE/
INDIRECT
SWITCH
POSITION
ZONE/
INDIRECT
SWITCH
POSITION
OTE: For proper operation of the boiler reset function, all heating thermostats must input to T-T or ZC-ZR terminals as indicated below.
Jumping the T-T terminals and wiring the thermostat to the primary will override the economy feature.
WIRING
WARNING E ectrica shock hazard. To prevent electrical shock, death or equipment damage, disconnect power supply before
installing or servicing this control.


CHOOSE OR BELOW
CHOOSE FROM THROUGH BELOW OR O PAGE 5 OR 6
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5
NOTE: The wire from ZR to the hot terminal of the indirect circulator will ensure
that indirect calls will fire to limit and receive priority over heating calls.
MULTIPLE CIRCULATORS — Typical Zone Panel with Priority Zone
ZONE/
INDIRECT
SWITCH
POSITION
ZONE/
INDIRECT
SWITCH
POSITION
SINGLE CIRCULATOR — Multiple Zone Valves including Indirect, No Zone Control Panel
STEP 3B: HEATING and Indirect Water Heater – continued
OTE: For proper operation of the boiler reset function, all heating thermostats must input to T-T or ZC-ZR terminals as indicated below.
Jumping the T-T terminals and wiring the thermostat to the primary will override the economy feature.
WIRING
WARNING E ectrica shock hazard. To prevent electrical shock, death or equipment damage, disconnect power supply before
installing or servicing this control.


MORE
NOTE: When using zone valves for both heat and indirect, the calls must be separated in order to prioritize indirect calls. This can
be accomplished by using a general purpose relay as shown above. owever, for ease of installation, a zone control panel is rec-
ommended (see wiring diagram 7 on next page).
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SINGLE CIRCULATOR — Typical Multiple Zone Valve Panel with Indirect
6
ZONE/
INDIRECT
SWITCH
POSITION
ZONE/
INDIRECT
SWITCH
POSITION
MULTIPLE CIRCULATORS — Typical Three Zone Switch Relay
STEP 3B: HEATING and Indirect Water Heater – continued
OTE: For proper operation of the boiler reset function, all heating thermostats must input to T-T or ZC-ZR terminals as indicated below.
Jumping the T-T terminals and wiring the thermostat to the primary will override the economy feature.
WIRING
WARNING E ectrica shock hazard. To prevent electrical shock, death or equipment damage, disconnect power supply before
installing or servicing this control.


NOTE – If a Zone Valve Control Panel has no priority zone: To ensure adequate boiler tempera-
ture to satisfy the domestic hot water tank, it may be necessary to turn the Economy Feature off.
NOTE: The wire from ZR to the hot terminal of the indirect circulator will ensure
that indirect calls will fire to limit and receive priority over heating calls.
Tacoʼs SR503 combines ZR amd X2.
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Zone/Indirect Switch
OTE: Settings can be checked using the
TEST/SETTINGS Button. See page 11 for details.
Setting the High Limit
The high limit is factory set at 190°F. To adjust, turn the I
TEMP Dial until the desired setting is displayed. (Setting
range: 100°-220°F)
Setting the Low Limit
The low limit is designed to maintain temperature in boilers
equipped with tankless coils used for domestic hot water.
The low limit is factory set to OFF. Prior to adjusting, remove
the jumper (not equipped on all units) . Then turn the LO
TEMP Dial clockwise until the desired temperature is dis-
played. For proper operation, the low temperature limit set-
ting should be at least 10° below the high limit setting.
OTE: For cold start operation, the low limit must be turned
OFF. IMPORTA T: If low limit temperature cannot be set
above 140°F, remove jumper . (Setting range: OFF or
110°-200°F).
Setting the Economy Feature
The Economy Feature is factory set for a 1 zone heating sys-
tem. To adjust, turn the ECONOMY Dial until the number
displayed equals the number of heating zones. Do not
include indirect water heaters in the number of heating
zones. The Economy Feature conserves fuel by reducing
boiler temperature (see “ ow Thermal Targeting Works” on
page 8). If the heating system is unable to supply needed
heat to the house, the ECONOMY Dial should be turned to a
lower setting (example: In a three zone house, turn the dial to
2 or 1). Conversely, if the boiler provides adequate heat,
added fuel savings can be achieved by selecting a higher set-
ting (example: 4 or 5). If the heating and indirect water heater
signals were not separated when wiring the control, the
Economy Feature should be turned OFF to ensure the boiler
supplies adequate temperature to heat the indirect tank.
Setting the Zone/Indirect Switch
See WIRING on page 4-6.
7
SETTING THE CONTROL
Dynamic
Display
Water Temperature
and Real Time
Verification of
Setting Adjustments.
Low Temperature
Limit Setting
(OFF or 110°-200°F)
Factory OFF
igh Temperature
Limit Setting
(100°-220°F)
Factory 190°F
Spade Connectors
for OS-100 Outdoor
Sensor Kit
Diagnostic LEDs



Economy Dial
(OFF or LO, 1, 2, 3,
4, 5, I)
Differentials
are automatic
and will vary
based on
control settings
and boiler tem-
perature.
SETTING
Disables economy function. Will allow boiler to fire until hi-
limit temp is reached and re-fire with a 10° subtractive
differential.
Provides lowest level of fuel savings. Use this setting only if
the house does not stay warm at higher settings.
Recommended setting for single zone systems
Recommended setting for Two zone systems
Recommended setting for Three zone systems
Recommended setting for Four zone systems
Recommended setting for Five zone systems
Provides highest level of fuel savings
Indicator Light
(announces heat call)
Jumper

Test/Settings Button
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8
OPTIONAL FEATURES
HOW THERMAL TARGETING WORKS
SYSTEM START-UP
Thermal Targeting technology analyzes thermostat activity and continually evaluates how much heat the house requires. When it
is very cold outside, the heat demand is high and the Fuel Smart ydroStat will raise the boilerʼs Target temperature to provide
needed heat to the home. When the outside temperature is milder, the heat demand is lower. During these periods, the Fuel
Smart ydroStat will lower the boilerʼs Target temperature – saving fuel – while continuing to provide comfort to the house.
At initial start up, with the Economy Feature active, the control establishes a 145°F target temperature. To test the high limit
shut-off function, the Economy Dial must be turned to OFF. Once tested, restore the Economy setting. If the heating demand is
high, the target will increase over time to satisfy the heat load.
OTE:
• Smart D W Priority: During a call from an indirect water heater, the control will de-energize the circulator contacts (C1/C2) to
heat only the indirect tank ensuring an adequate supply of domestic hot water. The control will re-energize the circulator when
the indirect tank is satisfied or if the boiler temperature reaches 170°F. If the indirect call continues for 45 minutes, the control
will override the priority function energizing the circulator to provide space heating.
NOTE: The Program Mode ––is accessed by turning the
LO TEMP dial to a position just above OFF.
Thermal Pre-Purge
Thermal Pre-Purge is designed to maximize boiler efficiency. When activated, the control will supply latent heat that may
remain in the boiler from a previous run cycle to the heating zone that is now calling. The control monitors how quickly the boil-
er temperature is declining and activates the burner only when it determines that the latent heat is insufficient to satisfy the call.
During the purge cycle, the display will indicate . This feature works with single-zone and multi-zone heating systems uti-
lizing circulators or zone valves. No change in wiring is needed.
To activate Thermal Pre-Purge
1. Turn the LO TEMP dial to access the Program Mode – indicated in the display as
2. Turn the I TEMP dial to select feature
3. Push the Test/Settings Button to turn Thermal Pre-Purge or
4. Reset LO TEMP and I TEMP settings to desired temperatures (see page 7)
Degrees Fahrenheit or Celsius
The control has the ability to operate in degrees Fahrenheit or Celsius. When operating in Celsius, a will appear in the dis-
play next to the temperature whenever the temperature is below 100 degrees.
To change between degrees Fahrenheit and degrees Celsius
1. Turn the LO TEMP dial to access the Program Mode – indicated in the display as
2. Turn the I TEMP dial to select feature
3. Push the Test/Settings Button to for Celsius or for Fahrenheit
4. Reset LO TEMP and I TEMP settings to desired temperatures (see page 7)
MORE OPTIONAL FEATURES ON NEXT PAGE
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9
OPTIONAL FEATURES continued
Manual Reset Low Water Cut-Off
The low water cut-off operation on the ydroStat can be set to operate in automatic (default) or manual reset mode. When in
manual reset mode, the control will shut-down the burner immediately when a low water condition is detected. If the low water
condition is sustained for 30 seconds, the low water light will blink, indicating that the control has locked out the burner. The
control can only be reset by pushing the Test Settings button on the top of the control. The manual reset feature meets CSD-1
code requirements.
IMPORTA T: The system must be checked by a qualified heating professional prior to resuming operation.
WAR I G: DO OT ADD WATER U TIL THE BOILER HAS FULLY COOLED.
To activate Manual Reset LWCO mode
1. Turn the LO TEMP dial to access the Program Mode – indicated in the display as
2. Turn the I TEMP dial to select feature
3. Push the Test/Settings Button to for Automatic Reset Mode or for Manual Reset Mode
4. Reset LO TEMP and I TEMP settings to desired temperatures (see page 7)
To Test the Manual Reset Feature: Press and hold the Test/Settings button located on the top of
the control for 30 seconds to simulate a low water condition. After 30 seconds, the Low Water light
will blink indicating that the control is locked out. To reset the lock-out condition, press the
Test/Settings button momentarily.
Circulator Activation Options
When in the default mode, the ydroStat activates the circulator (C1/C2 contacts) on calls to TT. The control can be pro-
grammed to activate the circulator on calls to ZC/ZR in place of, or in addition to, calls to TT.
To change how the Circulator is activated
1. Turn the LO TEMP dial to access the Program Mode – indicated in the display as
2. Turn the I TEMP dial to select feature
3. Push the Test/Settings Button to select between the following options:
- Circulator on TT call only
- Circulator on ZC/ZR call only
- Circulator on both TT & ZC/ZR calls
4. Reset LO TEMP and I TEMP settings to desired temperatures (see page 7)
Circulator Hold Off (Enhanced Condensing Protection)
To reduce the potential for condensing, on a call for heat the control will allow the boiler to heat to 125°F prior to energizing the
circulator. Once energized, the circulator will remain on for the duration of the heating call unless the boiler temperature drops
below 115°F. If this occurs, the circulator will re-energize when the boiler returns to 125°F.
To activate Circulator Hold Off
1. Turn the LO TEMP dial to access the Program Mode – indicated in the display as
2. Turn the I TEMP dial to select feature
3. Push the Test/Settings Button to turn Circulator old Off or
4. Reset LO TEMP and I TEMP settings to desired temperatures (see page 7)
MORE OPTIONAL FEATURES ON NEXT PAGE
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10
Low Water Cut-Off Function
To turn off Low Water Cut-Off
1. Turn the LO TEMP dial to access the Program Mode – indicated in the display as
2. Turn the I TEMP dial to select feature
3. Push the Test/Settings Button to turn Low Water Cut-Off or
4. Reset LO TEMP and I TEMP settings to desired temperatures (see page 7)
Restore Factory Default Settings
To restore all features to the factory default settings (see following chart for default settings)
1. Turn the LO TEMP dial to access the Program Mode – indicated in the display as
2. Turn the I TEMP dial to select feature
3. Push the Test/Settings Button to to reset all features to the default settings.
4. Reset LO TEMP and I TEMP settings to desired temperatures (see page 7)
Dial
Setting Feature Options Description Default Setting
1 Thermal Pre-Purge OFF
On
Purge Inactive
Purge Active
OFF
2 Fahrenheit or Celsius F
c
Degrees Fahrenheit
Degrees Celsius
F
3 LWCO Manual or
Automatic Reset
A
b
Automatic Reset
Manual Reset
A
4 Circulator Options A
b
C
Circulator operation on TT call only
Circulator operation on ZC/ZR call only
Circulator operation on call from either
A
Circulator old Off
Circulator old Off – Active
Circulator old Off – Inactive
Not available
on this control
Not available
on this control
Low Water Cut-Off
Function
Low Water Cut-Off ON
Low Water Cut-Off OFF
dEF Restore Factory
Defaults
Y
n
Restore Defaults
Do Not Restore Defaults
n
NOTE: If the ydroStat is factory-equipped on a boiler, some options may be set differently from the default settings.
SEE PAGE 7 FOR ADDITIONAL SETTINGS
OPTIONAL FEATURES continued
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11
 TEMP ACTIVE Indicates that the Fuel Smart
ydroStat control is powered and that the temperature
function is active.
 TEMP HI TEMP Illuminates when the boiler water
temperature reaches the high limit setting. It will remain lit
until the water temperature falls 10°. The Fuel Smart
ydroStat prevents burner operation while this LED is on.
See Differential explanation on page 7.
 LWCO ACTIVE Indicates that the low water cut-off
(LWCO) function of the Fuel Smart ydroStat is active. When
the control is installed with a ydrolevel Electro-Well™, this
LED will be on at all times when the control is powered.
IMPORTA T: If the control is installed with a well other than
the Electro-Well™, this LED will not illuminate indicating that
the control is not providing low water cut-off functionality.
 LWCO LOW WATER Indicates that the boiler is in a
low water condition. The ydroStat control will prevent
burner operation during this condition. If the LOW WATER
light is blinking, the control has been programmed to provide
lock-out protection in the event a low water condition is
detected (see Manual Reset Low Water Cut-Off on page 9).
Pressing the TEST/SETTINGS button will reset the control.
IMPORTA T: The system must be checked by a qualified
heating professional prior to resuming operation.
WAR I G: ALLOW THE BOILER TO FULLY COOL
BEFORE ADDI G WATER.
 ECONOMY ACTIVE Indicates that the Thermal
Targeting function is active and the Fuel Smart ydroStat will
reduce boiler temperature to conserve fuel. The Economy
feature is activated using the ECONOMY dial. (See “ ow
Thermal Targeting Works” on page 8 for more information).
 ECONOMY TARGET When the Economy feature is
active, the Fuel Smart ydroStat continually sets target
temperatures below the high limit setting to maximize fuel
efficiency. When the boiler water reaches the target
temperature, the LED illuminates and the burner will shut
down. The boiler water will continue to circulate and heat the
house as long as the thermostat call continues. The LED will
stay lit until the boiler temperature drops below the
differential set point at which point the boiler will be allowed
to fire again. See Differential explanation on page 7.
OTE: This LED illuminates regularly during normal boiler
operation.
 TEST/SETTI GS Button
To Test Low Water Cut-Off: Press and hold the Test/
Settings button for 5 seconds. The display will read LCO.
LWCO TEST 00
The red Low Water light should illuminate and the burner
circuit (B1 and B2) should de-energize. OTE: The control
must be installed with a ydrolevel Electro-Well™ for low
water cut-off functionality (see page 2 for more details).
To View Current Settings: Press and release the
Test/Settings Button in short intervals to sequentially display
the following settings:
HIGH LIMIT SETTI G 00

LOW LIMIT SETTI G 00

ECO OMY SETTI G 000

CURRE T TARGET TEMPERATURE
The display will return to boiler temperature (default) if
Test/Settings Button in not pressed for 5 seconds.
LED LEGEND and TEST/SETTINGS BUTTON
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12
MAINTENANCE
Remove the Electro-Well™ from the heating system every five years and clean any scale or sediment deposits from all parts that
are exposed to the boiler water. After cleaning, reinstall the well using pipe sealing compound. Teflon tape is not recommended.
TROUBLESHOOTING
Burner Will ot Fire See Flow Chart 1, page 13
Burner Will ot Shut Down See Flow Chart 2, page 14
Temperature Display Exceeds
High Limit Setting
Under normal operation, boiler temperature will continue to rise after the control shuts off
the burner. This condition, known as “thermal stacking”, results from hot boiler surfaces
continuing to release heat into the boiler water.
o or Insufficient
Domestic Hot Water
For boilers equipped with a tankless coil, make sure the low limit setting on the ydroStat
is set properly. OTE: If the low limit setting is dialed fully counter clockwise, it will shut
off the low temperature maintenance feature and will function as a cold start control. If
installed with an indirect water heater, check that the Zone/Indirect Switch is set in the
Indirect (I) position. Verify that the end switch in the relay box controlling the indirect water
heater is connected to the ZC-ZR terminals. This will ensure that the domestic water calls
are prioritized. (see “ eating and Indirect Water eater” on page 4-6).
Low Water Light
(Red LED) is On
or Blinking
WAR I G: A low water condition is a serious and potentially
dangerous condition. Do not attempt to add water to a hot boiler.
Allow the boiler to fully cool before adding water.
When Installed on an Electro-Well™
When the LOW WATER light is on, this indicates that the control is not detecting water in
the boiler. When the LOW WATER light is blinking, this indicates that the control has
been programmed to provide low water lock-out protection and is currently locked out
(see Manual Reset Low Water Cut-Off on page 9). Pressing the TEST/SETTINGS button
after the low water condition is resolved will reset the lock-out condition.
1. If the light is on and the heating system is filled with water, pull the sensor out of the
well and inspect it. Make sure that the metal clip is protruding enough to come in
contact with the inside of the well tube. Check that the well does not have excessive
build-up of heat transfer grease that may interfere with the clip contacting the well.
2. Remove well and examine for excessive residue build-up. Clean and re-install.
When Installed on a Standard Immersion Well
If either LWCO LED lights are illuminated and the control is installed on a standard
immersion well, this is a false reading caused by a loss of continuity between the sensor
and the inside of the well tube. It is recommended when the control is installed on a
standard immersion well, the LWCO Function be turned off (see page 10 for details).
Boiler Will ot Maintain
Low Limit Temperature
Check for overlapping high temperature setting. If the high limit setting is set below the
low limit setting, the control will default to the high limit setting and the corresponding
high limit differential setting.
House Will ot Get
or Stay Warm
1. Check for air-bound radiators.
2. Check thermostat settings including heat anticipator settings (common on non-digital
thermostats).
3. Check the Economy setting. The Economy feature, much like outdoor reset controls,
lowers average boiler temperature and can slow or, in some cases, prevent the house
from coming up to temperature. Move to a lower setting (see “Setting the Economy
Feature” on page 7).
Circulator Contacts
C1 and C2 ot Energized
on Call for Heat
Check to see that boiler water is at or above 125°F. On a call for heat, the control will not
permit the circulator to operate if the boiler water temperature is below 125°F (see
“Circulator old Off” on page 9).
All LED Lights and Temp
Display are Blinking
If the LED lights and the temp display are blinking alternately, this indicates the control has
sensed a boiler temperature of 250°F. When this occurs, the control pulses the burner relay
and then shuts down and locks-out the burner. The system should be analyzed to determine
the cause of the overheating condition. Check that the sensor is inserted all the way into the
well so it can accurately sense the temperature of the boiler water. Check the load on the
burner contacts: If the load exceeds the 7.4 Amp rating, the contacts may have welded.
Correct the overloading condition and replace the control before reenergizing the system. If
the load on the contacts is below the rating, check system wiring and operation as well as the
controlʼs high limit setting. If the cause of the overheating is found and the system is deemed
safe, the control can be reset by removing power from the control and then repowering while
simultaneously pressing the Test/Settings button on the top of the control. If the cause of the
overheating condition is not determined, the control should be replaced.
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13
O
YES O
Is the
Thermostat
(T-T) Calling
for Heat?
Is There
120 VAC
Between B1
and B2?
O
Is the
External Zone
(ZC-ZR) Calling
for Heat?
O
Is the
Low Limit Dial
Set to OFF?
YES
O
YES
Is the
Red LED
(LOW WATER)
On?
The Control is
Sensing
Low Water.
CAUTION – ALWAYS ALLOW A BOILER TO COOL BEFORE ADDING WATER
The burner will not fire until the low water condition is satisfied.
Check that the system is filled with water.
Check that the sensor is inserted fully into the well and contact
between its spring clip and the copper well tube is made.
Check that the control is tightly clamped to the well.
Also see page 12 for additional tro bleshooting information.
Is the
Yellow LED
(HI TEMP)
On?
The Control is
Sensing High
Temperature.
If both the red and yellow LEDs are off and
there is a call to fire the burner, there will be
120 VAC on terminals B1 and B2.
If 120 VAC is not present, the control should
be replaced.
HydroStat is supplying 120 VAC to the burner circuit.
Recheck wiring and operation of burner and other limit controls.
The Control
is Operating
Properly.
Replace
Control
The burner will not fire until the boiler water has dropped to the
high limit differential set-point (10° below high limit setting).
Check that the high temperature setting is correct.
Troubleshooting Flow Chart 1 – Burner Will ot Fire
YES
YES
O
Is the
Yellow LED
(TARGET)
On?
The Boiler has
Reached the
Target
Temperature.
When the ECONOMY function is active, the control monitors heating
demand and establishes Target boiler temperatures below the high
limit setting to conserve fuel (see “How Thermal Targeting Works”
on page ). The burner will not fire until the boiler temperature
drops to the automatically calculated Target Temp Differential.
YES
O
Is the
Green LED
(TEMP ACTIVE)
On?
The Control is
Not Powered.
The Temp Active LED will be on at all times when the control is
powered.
Check for 120 VAC on terminals L1 and L2.
YES
O
When the low temperature
setting is set to OFF, the
HydroStat will act as a cold
start control. The burner
will not fire unless there is
a call from the thermostat
(T-T) or an external zone
(ZC-ZR).
Set thermostat to call
for heat. Burner should
fire.
If the boiler has a tank-
less coil, set the Low
Temperature Limit to
maintain temperature.
YES
Does the
Display Read
?
The Control is
Purging Latent
Heat from the
Boiler.
The Thermal Pre-Purge feature holds off the burner until the
control determines if the latent heat in the boiler can satisfy
the heat call.
O
YES
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14
YES
Recheck
Wiring.
Replace
Control.
When there is no call to fire the burner, the voltage
should be 0 volts between B1 and B2.
 Make sure the burner is wired to B1.
YES
O
Is the
Low Limit Dial
Set to OFF?
Is there
120 VAC between
B1 and B2?
O
Is the
Thermostat
(T-T) Calling
for Heat?
YES
YES
Is the
External Zone
(ZC-ZR) Calling
for Heat?
O
O
Is the
Red LED
(LOW WATER)
On?
The Control is
Sensing
Low Water. WAR I G!
TURN OFF POWER TO BURNER IMMEDIATELY!
CAUTION – ALWAYS ALLOW A BOILER TO FULLY COOL
BEFORE ADDING WATER.
Recheck wiring. Make sure that burner is wired to
B1. Burner should never fire when red or yellow
LED is lit.
Is either
Yellow LED
On?
The Control has
Reached Target
or High Limit
Temperature.
The Control is
Operating
Normally.
The Control is
Operating
Normally.
The burner will continue to fire when there is a call
from the thermostat or external zone.
 Check temperature display. When the Low Limit is
set, the HydroStat will fire the burner until the
temperature reaches the Low Limit Setting.
If there is no call for heat (from T-T, ZC-ZR or Low
Limit), there should be 0 VAC between B1-B2.
 If there is voltage between B1-B2, the control
should be replaced.
Troubleshooting Flow Chart 2 – Burner Will ot Shut Down
YES
YES
O
O
HydroStat 3250-Plu In truction : HydroStat In truction .8pg 11/14/13 3:43 PM Page 14

15
ELECTRO-WELLS™
Fuel Smart HydroStat
installed with Electro-Well™
When installed with the ydrolevel Electro-Well™,
Fuel Smart ydroStat will provide both temperature
and low water cut-off functionality. If the control was
supplied by the boiler manufacturer, it was installed
with an Electro-Well™. The Electro-Well™ is available
separately for field installations.
Electro-Well™ Models
IIMMPPOORRTTAANNTT::
For proper opera-
tion of the low
water cut-off func-
tion, there must
be a minimum of
½" clearance
between the cop-
per well tube and
any surface within
the boiler.
HydroStat 3250-Plu In truction : HydroStat In truction .8pg 11/14/13 3:43 PM Page 15

16
83 Water Street • New Haven, CT 06511 • Phone [phone] • FAX [phone] • www.hydrolevel.com
REMOTE MOUNTING KITS
OUTDOOR SENSOR KIT
ydrolevel's optional Outdoor Sensor Kit automatically activates outdoor reset functionality and warm weather shutdown capa-
bility when plugged in to the Fuel Smart ydroStat control. This low cost, easy to install kit is available separately at ydrolevel
distributors.
Part No. Description
48-140 Model OS-100 Outdoor Sensor Kit
Part No. Description
48-101 ydroStat Remote Mount Kit with 24" sensor
48-102 ydroStat Remote Mount Kit with 48" sensor
Part No. Description
48-103 ydroStat Remote Mount Kit with 10' sensor
48-104 ydroStat Remote Mount Kit with 20' sensor
48-121 ydroStat Pipe Mounting Kit with 48" sensor
SPECIFICATIONS FUEL SMART HYDROSTAT MODEL 3250-Plus
DIMENSIONS
LIMITED MA UFACTURERʼS WARRA TY
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 pur-
chase 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 conse-
quential. 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.
Input voltage 120 VAC, 60 Z
Burner contacts 7.4 FLA, 44.4 LRA@120 VAC
Circulator contacts 5.8 FLA, 34.8 LRA@120 VAC
Operating range – low limit Off or 110°F (43°C) - 200°F (93°C)
Operating range – high limit 100°F (38°C) - 220°F (104°C)
Operating range – differentials Automatic
Thermostat heat anticipator setting 0.2A
3250-1113
HydroStat 3250-Plu In truction : HydroStat In truction .8pg 11/14/13 3:43 PM Page 16