Install Instructions

ManualsBrandsTaco ManualsHeating SuppliesElectronic, (24V) Low Water Cut-Off (Water), 3/4" NPT

General:

The Residential Low Water Cutoff (LTR) is a microprocessor based

low water cutoff for detecting the presence to water in a boiler. The

LTR uses advanced signal processing to identify when the probe

signal levels have decreased due to possible fouling. These advanced

technologies permit extended operation for probe impedance up to 40K

Ohms. The LTR functions longer without requiring probe cleaning, and

it functions normally under non-ideal installation conditions. The LTR is

designed for use with hot water boilers and hot water heating boilers.

(See each boiler manufacturers' speciﬁ cations for recommended

minimum safe water levels.)

During a low water condition, the "Status" LED will illuminate RED.

Under normal conditions, it will illuminate GREEN. See "Status LED

States" table for details.

Instruction Sheet

LTR - Low Water Cutoff

for Hot Water Boilers

102-338

SUPERSEDES: Revision D Dated January 6, 2009

#5401179-REV E PLANT ID 001-3907

EFFECTIVE: December 2, 2009

Listings/Approvals:

• UL GUIDE (MBPR) for Limit Controls per UL Standard

353 Limit Controls

• UL GUIDE (MBPR7) Controls, Limit Certiﬁ ed for Canada

CSA Standard C22.2

Maximum Probe Ratings:

Hot water only - 160 psi (11.2kg/cm

) at 250°F (121°C)

Probe Sensitivity: 20K Ohms. Extended operation to 40K Ohms.

Ambient Temperature: 32°F - 120°F (0°C to 49°C)

Enclosure Rating: NEMA 1 for indoor use only

Input Power: 1.5 VA @ 24 VAC supplied by a Class 2 power source

Output Contact: Form B Relay, normally closed (water detected)

5A @ 24 VAC maximum load,

50 VA @ 24 VAC switching

Reset: Automatic reset when water level returns to safe level

Testing: Integrated test switch for testing safety shutdown

US Patents 6,904,800, 7,243,540,

and 7,317,993

Other Patents Pending

• Installation must be performed by qualiﬁ ed personnel and in accordance with all national and local codes and ordinances.

• Read all instructions carefully and understand them before starting installation. Save instructions for future use.

• Instruct user how to test and operate this cutoff device as described in these instructions.

• Risk of explosion. Not for use in hazardous locations. Serious injury or death could result.

• The LWCO device must be installed in series ahead of other limit and operating controls installed on the boiler. When installations are complete,

check for correct operation of ALL limit and operating controls.

• For use with hot water boilers and hot water heating boilers only. Use on steam boilers could cause improper operation resulting in property damage,

serious injury, and death.

• Shock Hazard. Disconnect power source before servicing. Serious injury or death could result.

• Use only the wiring harness supplied with the control or factory supplied alternates. Use of other wire harness or insulation types could result in ﬁ re

causing property damage, serious injury, or death.

• Hot or pressurized boiler systems can discharge steam and hot water. Cool boiler system to 80º F (27º C) and to 0 psi (0 bar) before servicing.

Failure to do so could result in serious burns.

Summary of content (6 pages)

PAGE 1
Instruction Sheet LTR - Low Water Cutoff for Hot Water Boilers SUPERSEDES: Revision D Dated January 6, 2009 #5401179-REV E PLANT ID 001-3907 102-338 EFFECTIVE: December 2, 2009 Listings/Approvals: • UL GUIDE (MBPR) for Limit Controls per UL Standard 353 Limit Controls • UL GUIDE (MBPR7) Controls, Limit Certified for Canada CSA Standard C22.2 Maximum Probe Ratings: Hot water only - 160 psi (11.2kg/cm2) at 250°F (121°C) Probe Sensitivity: 20K Ohms. Extended operation to 40K Ohms.
PAGE 2
Process Connection LTR Features: LTR Connector Service LED (Amber) Status LED (Bi-color) Test Button Probe Item Description Status LED Bi-color LED status indicator. See "LED States" table for details. Service LED Amber LED indicator that service is needed on LTR or system. Test Button Push button switch for testing safety shutdown of boiler controls. LTR Connector Power and relay contact connector.
PAGE 3
Fig. 3 1.00 2.66 .79 1.79 1.79 3/4” NPT DWG# 1179-1 Wiring for Boilers with Honeywell Aquastat Models L8124E or L8148E or Equivalent: L8124E Factory Wiring Factory Wiring L8148E RED Female Connector Female Connector WHITE RED Male Connector Male Connector E WHIT OW LL YE Ground Screw OW LL YE OW LL YE N EE GR OW LL YE Ground Screw GR EE N • Shock hazard. Disconnect power source before servicing. Serious injury or death could result.
PAGE 4
Alternate Wiring: 24 VAC Class 2 Transformer Limit Controls LL W LL O YE COMMON YE 24 VAC RED 120 VAC OW HOT W HI TE Gas Valve GREEN Wiring Instructions 1. Connect the WHITE wire to the transformer's common connection. 2. Connect the RED wire to the transformer's hot output. 3. Connect the GREEN wire to a ground source that is electrically common to the boiler ground. 4. Cut off the quick connectors from both YELLOW wires and strip the wire ends. 5.
PAGE 5
Wiring Boilers with an Integrated Control Module and OEM 4-pin Harness: 4-pin Connector (#1) Integrated Control Module 4-pin Connector (#2) Wiring Harness Wiring Instructions 1. Plug the 4-pin connector on the wiring harness (#1 as shown) into the integrated control module. 2. Plug the 4-pin connector on the wiring harness (#2 as shown) into the LTR. Testing: 1. DO NOT fill the boiler. Set the thermostat to lowest possible setting and turn on electric power to the boiler.
PAGE 6
Troublshooting: Symptom Boiler will not fire Boiler will not shutdown Amber "SERVICE" LED is on Possible Cause Remedy No power to LTR Verify that the LTR wiring harness is plugged into the LTR and wiring is correct. Be sure power to boiler is turned on. Low water level Make sure that the water level has reached the LTR probe. Air pocket at LTR probe Turn off power to the boiler and slowly loosen, but do not remove the LTR. Allow any air to escape until water seeps past the LTR's threads.