Install Instructions

ManualsBrandsTaco ManualsHeating SuppliesElectronic, (24V) Man. Reset 3/4" NPT Low Water Cut-Off, Remote Probe w/ NEMA 4 Enc. (Water)

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

and 7,317,993

Other Patents Pending

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' speci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 F Dated December 17, 2012

#5401179-REV G PLANT ID 001-3907

EFFECTIVE: June1, 2017

Listings/Approvals

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

353 Limit Controls

• UL GUIDE (MBPR7) Controls, Limit Certi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)

LTR024 Models

5A @ 24VAC Max Load

50 VA @ 24VAC Switching

Reset:

Automatic Model: Automatic reset when water level returns to safe

level

Manual Model: Press RESET Button when water level returns to safe

level

Testing: Integrated test switch for testing safety shutdown

• Installation must be performed by quali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 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 F Dated December 17, 2012 #5401179-REV G PLANT ID 001-3907 102-338 EFFECTIVE: June1, 2017 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
Automatic Model: Pressing the TEST button with the LTR in a Normal condition with water covering the probe will cause the LTR to enter a Low Water Condition. Manual Model: Pressing the TEST/RESET button for two seconds while the LTR is in a Low Water Condition will reset the LTR provided water covers the probe. Pressing the TEST/RESET button with the LTR in a Normal condition with water covering the probe will cause the LTR to enter a Low Water Condition.
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 Male Connector Female Connector Female Connector WHITE RED • Shock hazard. Disconnect power source before servicing. Serious injury or death could result. • Only use the wiring harness supplied with the control or factory supplied alternates.
PAGE 4
Alternate Wiring: 24VAC Systems LTR024 Models Only 24 VAC Class 2 Transformer Limit Controls W LL O YE W LL COMMON YE 24 VAC RED 120 VAC OW HOT 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.