ThermoFlow Hydrex 18 User Manual (English)

Questions and Answers:

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Paul ColonAug 17, 2025
Why is my ThermoFlow Water Heater heating, but the water is not hot enough?
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  Jacob HowellAug 17, 2025
  There are several reasons why your ThermoFlow Water Heater might not be producing hot enough water: * The user temperature setting may be too low - try increasing it. * The flow rate might be too high; consider installing a flow regulator to reduce it. * If it’s a new installation, the wiring could be incorrect; have your electrician double-check it. * The voltage may be less than 380 volts for 3-Phase models or less than 220 volts for Single-Phase models. In this case, you may need to upgrade to a larger input heater. * You might be mixing too much cold water; adjust your faucet's anti-scald feature to reduce cold water mixing.
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Zachary HallAug 22, 2025
How to fix a ThermoFlow Hydrex 18 Water Heater when it's not heating and the display is off?
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  ramirezwilliamAug 22, 2025
  If your ThermoFlow Water Heater isn't heating and the digital display is off, it could be due to no power or incorrect wiring. First, ensure the breakers at your main electrical panel are turned ON. It's also possible you have a faulty breaker or that the unit is wired incorrectly. You may need to have an electrician check the wiring.
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Stephen ClarkAug 25, 2025
What to do if ThermoFlow Hydrex 18 Water Heater is not heating but the display is on?
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  Gary RodriguezAug 25, 2025
  If your ThermoFlow Water Heater's digital display is on, but the water isn't heating, the issue might be: * Flow rate is too low / water pressure is too low. Your water heater needs approximately 0.6 GPM (2.5 LPM) to activate. Increase the flow rate or check the filter mat inside the inlet connector. * The air bubbles in the water heater have not been purged out. Make sure the breakers at the main electrical panel are ON, turn on the unit, and open the hot water tap for about 20 seconds.
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smithkimberlyAug 27, 2025
How to troubleshoot ThermoFlow Water Heater when the digital display doesn't light up?
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  Calvin LopezAug 27, 2025
  If your ThermoFlow Water Heater's digital display isn't lighting up and the water isn't heating, first, ensure the breakers at the main electrical panel are ON. You might have a faulty breaker or the unit could be wired incorrectly.
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Nathan FloresAug 30, 2025
Why is the water temperature at the faucet different from my ThermoFlow Hydrex 18 Water Heater setting?
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  Anthony AguilarAug 30, 2025
  The water temperature at the faucet differing from your ThermoFlow Water Heater setting can be due to a few reasons: * Your faucet might have an anti-scald feature or tempering valve that mixes cold water, even on full hot. Adjust the valve to reduce cold water mixing. You can compensate for this by increasing the setting on your water heater if you need/want hotter water. * Heat loss can occur due to long pipe runs, especially if the pipes are cold. You can compensate for this by increasing the setting on your water heater if you need/want hotter water. * If the water temperature at the faucet is too hot, check if the flow is too little or the set point temperature is too high.
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Colleen HollowaySep 2, 2025
How to fix low flow rate on ThermoFlow Hydrex 18?
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  Rhonda McintoshSep 2, 2025
  If you're experiencing a low flow rate with your ThermoFlow Water Heater, the filter mat inside the inlet connector or the pipe might be blocked. Check and clean the filter mat inside the inlet connector to resolve this issue.
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Hannah Romero MDSep 7, 2025
Why is the water temperature different from my ThermoFlow Hydrex 18 Water Heater setting?
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  Ronald DavisSep 7, 2025
  The water temperature at the faucet might differ from your ThermoFlow Water Heater setting due to: * An Anti-Scald pressure/balancing valve or tempering valve. These may automatically mix cold water, even on full hot. Adjust these devices to reduce cold water mixing. You can also increase the water heater setting to compensate. * Thermal loss due to a long pipe run. Heat loss can occur as hot water travels, especially over long distances or through cold pipes. Increase the water heater setting to compensate. * Water temperature at the faucet is too hot. Check your flow for too little flow, set point temperature is too high.
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Kelsey GregorySep 10, 2025
How to increase the flow rate on my ThermoFlow Hydrex 18?
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  Jennifer JacksonSep 10, 2025
  A low flow rate in your ThermoFlow Water Heater may be due to a blockage. Check and clean the filter mat inside the inlet connector. Also, inspect the pipe for any blockages.
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Mallory OwensSep 10, 2025
What to do if my ThermoFlow Water Heater display lights up but shows no temperature and isn't heating?
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  Katherine PorterSep 12, 2025
  If your ThermoFlow Water Heater's display lights up but shows no temperature and isn't heating, it could be due to several reasons: * The flow rate might be too low. Your water heater needs a flow rate of approximately 2.2L/min / 2.5L/min to activate. Increase the flow rate or check the filter mat inside the inlet connector. * Air bubbles might be trapped. Turn on the unit and open the hot water tap for about 20 seconds to purge them. * The flow sensor might be blocked. Try uninstalling and cleaning it. * The connector between the flow sensor and the main board might be loose. Unplug and replug it.
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Courtney TurnerSep 13, 2025
What does error code 'E2' mean on my ThermoFlow Hydrex 18?

ThermoFlow Hydrex 18 Specifications

General

Category	Water Heater
Voltage	240 V
Amperage	75 A
Wattage	18 kW
Wire Gauge	8 AWG
Water Connection	3/4" NPT
Temperature Range	86°F to 140°F
Required Breaker Size	80A