TROUBLESHOOTING

 

NOTICE: READ THE GENERAL SAFETY SECTION OF YOUR OWNERS MANUAL BEFORE TROUBLESHOOTING THIS UNIT.  IF YOU DON’T FOLLOW THESE SAFETY RULES, THE UNIT MAY NOT OPERATE PROPERLY AND COULD CAUSE, SERIOUS BODILY INJURY, PROPERTY DAMAGE AND/OR DEATH.

 

WARNING: HAZARD OF ELECTRICAL SHOCK! BEFORE REMOVING THE COVER OR SERVICING THE UNIT, MAKE SURE THE ELECTRICAL SUPPLY TO THE WATER HEATER IS DISCONNECTED. FAILURE TO DO THIS COULD RESULT IN DEATH, SERIOUS BODILY INJURY, OR PROPERTY DAMAGE. DEPENDING ON YOUR INSTALLATION, IT MAY BE NECESSARY TO TURN OFF MULTIPLE BREAKERS TO COMPLETELY POWER DOWN YOUR UNIT.

 

General:

All Seisco models are self diagnosing with a single LED on the control board.  Under normal operation the LED will blink continuously green.  When a fault occurs, a multi-digit code or codes will be displayed.  If you have difficulty understanding the code, you can press and hold the button on the board for 1 second and the code will be announced through the on board piezo-electric speaker.  This is helpful when working with a Seisco technician by phone.  Download the quick-service guide below for a table of service codes and definitions for your model.

 

When troubleshooting a Seisco model there are a few basic tools required.  A phillips style screwdriver and a digital voltmeter with a clamp style voltmeter.   A description of all troubleshooting steps and tests are described in the service guide.

 

No Hot Water

There are three primary things that must be working correctly to produce hot water from a Seisco Tankless.  The control board; the temperature sensors; and the heating elements.  If you receive a code 122 that indicates an overtemperature condition, first reset the limit switch, then isolate the component causing the over temperature condition.  Avoid the temptation to replace the limit switch, the cause is almost always elsewhere in the heater.  Likewise an element code is often the result of a failed temperture sensor.  Whenever your heater is malfuntioning, perform the complete troubleshooting procedure to ensure all components of the heater are working correctly.  On a new installation, turn the water off after purging all of the air from the unit and wait a few minutes before activating the power the first time.  The unit will not activate if you turn the power on with the hot water already flowing.

 

Not Enough Hot Water

If you have insufficient hot water, first you must determine if your unit is adequately sized for the current conditions.  If the amp meter is reading the maximum rating at all elements and your hot water is insufficient, you must either reduce the flow rate at the fixtures or increase the size of your Seisco. Techniques to reduce flow include flow-restricting aerators for faucets and low-flow showerheads.  Contact Seisco customer service for assistance.  Tub fillers should be limited to a maximum of 1/2" plumbing line when sizing a single Seisco whole-house tankless.  Temporarily restrict flow with the ball shutoff valve to verify a sizing issue.  If this is a new installation, verify that the water is flowing in the correct direction in the inlet and out the outlet.  If jumpers are required on the circuit board, verify correct installation.

 

Fluctuating Temperatures

Primary reason for fluctuating temperatures is under-sizing.  See Not Enough Hot Water.  If heater is adequately sized perform the complete troubleshooting procedure to isolate issues with the circuit board, sensors and heat elements.  Verify that there is no reverse flow.  A spring type check valve should be installed on the outlet if the plumbing design could result in reverse flow.  If this is a new installation, does issue only occur at certain locations.  Pressure balancing valves may need to be adjusted to provide adequate hot water.  Scald prevention devices may also require adjustment.  Verify that the water is flowing in the correct direction in the inlet and out the outlet.  If jumpers are required on the circuit board, verify correct installation.

 

Click here for Troubleshooting Guide

Tankless Water Heater

Seisco   241 Airtex Drive, Houston, TX  77090    888.296.9293  (281.876.3300 outside the U.S.)     seiscosales@hotwater.com