Intellihot iQ251 - User Manual

Questions and Answers

J
josephharveyAug 15, 2025
Why does my Intellihot Water Heater have ignition failure?
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  youngtoddAug 15, 2025
  If your Intellihot Water Heater is experiencing ignition failure, it could be due to several reasons. First, the water over-heat switch might have tripped, in which case you should check the pump and cross over solenoid, also consider electrical noise. Other potential causes include a faulty DSI, igniter wire, ignition connection, PCB, or a bad igniter, requiring a replacement of the part. Low gas pressure could also be the culprit; try adjusting the gas pressure at the regulator, checking or upsizing the gas line, and inspecting for gas line blockages. If the problem persists, turn the control panel OFF, shut the gas valve, and unplug the unit, then contact an authorized service technician.
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Ryan WilliamsAug 18, 2025
What to do if my Intellihot Water Heater shows a blocked flue fault?
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  Charles PatelAug 19, 2025
  If your Intellihot Water Heater shows a blocked flue fault, the exhaust might be obstructed by something like a bird. Inspect the exhaust termination and connection at the water heater, and consider installing screens. Another cause could be backed-up condensate; check the slope of the drain and look for double loops, air locks, or debris in the loop. Also, check the wiring, as a loose connection could trigger the fault.
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Samantha SimonAug 21, 2025
Why does my Intellihot Water Heater show 'Flue Temperature Exceeded Set Limit'?
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  Jamie TuckerAug 22, 2025
  If the flue temperature on your Intellihot Water Heater exceeds the set limit, it could be due to several factors. First, verify that the vent pipe material is correctly set in the FP (Flue Pipe) mode if you're using CPVC or Polypropylene. High inlet temperature can also cause this issue; ensure it's below 150°F for PVC vents or 190°F for CPVC or Polypropylene vents. Check for nicked or broken sensor wiring and connectors, as well as any corrosion or moisture. You may also need to measure the sensor's resistance at the connector (18 Kohm at 50°F, 10 Kohm at 77°F, 3 Kohm at 140°F). If none of these steps resolve the problem, the controller might be faulty and require replacement.
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Charles RamosAug 26, 2025
What causes Heat Exchanger outlet temperature exceeded set limit in Intellihot Water Heater?
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  Todd PhillipsAug 26, 2025
  If the heat exchanger outlet temperature on your Intellihot Water Heater exceeds the set limit, it could be due to excessive flow rate changes. Ensure the water flow rate doesn't change faster than 2 GPM every 5 seconds. Also, check for any damaged sensor wiring or corroded connectors. Measure the resistance of the sensor at the connector (18 Kohm at 50°F, 10 Kohm at 77°F, 3 Kohm at 140°F). If the issue persists, the controller may be faulty and require replacement.
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seth77Aug 29, 2025
How to fix a Temperature Sensor Shorted error on my Intellihot Water Heater?
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  Johnathan SmithAug 29, 2025
  If your Intellihot Water Heater indicates a temperature sensor shorted, it could be due to faulty sensor wiring. Check for nicked or broken sensor wiring or connectors, and also look for corroded or wet connectors. Another possibility is a faulty sensor; measure its resistance at the connector (18 Kohm at 50°F, 10 Kohm at 77°F, 3 Kohm at 140°F). If the issue relates to the heat exchanger water outlet, flue, or inlet water temperature sensor, consider replacing the controller. A faulty controller can also cause this issue, so replacing it might be necessary.
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zwaltersSep 1, 2025
What causes a Temperature Sensor Open Circuit in Intellihot Water Heater?
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  Nathaniel DuranSep 1, 2025
  If your Intellihot Water Heater shows a temperature sensor open circuit error, start by checking the connectors to ensure they are securely connected. Inspect the sensor wiring for any nicks or breaks, and look for corroded or wet connectors. If the wiring seems fine, measure the resistance of the sensor at the connector (18 Kohm at 50°F, 10 Kohm at 77°F, 3 Kohm at 140°F). If the problem persists, it could be related to the heat exchanger water outlet, flue, or inlet water temperature sensor, which may require replacing the controller. A faulty controller itself can also cause this issue, necessitating its replacement.
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felicia39Sep 4, 2025
How to troubleshoot a Blower Speed Fault on an Intellihot Water Heater?
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  walkeremilySep 4, 2025
  If your Intellihot Water Heater is experiencing a blower speed fault, it could be due to a noisy or jammed blower. Inspect the blower and impeller, cleaning and removing any obstructions. Another potential cause is a disconnected signal wire; check the PWN signal and look for loose wires or pins, repairing as necessary. If the wiring is faulty, again check the PWN signal and repair any loose wires or pins. If the problem persists, turn the control panel OFF, shut the gas valve, unplug the unit, and contact an authorized service technician.
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Samantha McguireSep 7, 2025
What does a flashing cascade icon mean on my Intellihot Water Heater?
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  gjacksonSep 8, 2025
  If the cascade icon is flashing on your Intellihot Water Heater, it indicates a loss of communication between units. Check the communication cable for breaks or nicks and ensure the connector is secure. Make sure the communication cable isn't bundled with high voltage lines. Verify the dip switch (SW3) is ON in the first and last units and OFF in all other units. Also, ensure each unit numbering is unique under the dC mode.
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nwatsonSep 12, 2025
What to do if the icon is flashing on my Intellihot Water Heater?
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  garciawilliamSep 12, 2025
  If you see a flashing icon on your Intellihot Water Heater, it means there's an error code and the unit has locked out. To resolve this, refer to the specific error code (E1, E2, etc.) indicated.

Intellihot iQ251 Specifications

General

Model	iQ251
Category	Boiler
Thermal Efficiency	95%
Minimum Water Flow Rate	0.5 GPM
Fuel Type	Natural Gas or Propane
Voltage	120V
Water Connection Size	3/4" NPT
Gas Connection Size	3/4" NPT
Weight	60 lbs
Type	Tankless
Hot Water Flow Rate	6.6 GPM at 45°F rise
Electrical Requirements	120V, 60Hz, 1.5A
Vent Diameter	3 inches

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Intellihot iQ251 - User Manual

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Questions and Answers

Intellihot iQ251 Specifications

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