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Blog Series - Water Heaters: Back to Basics, Part Two


Our Blog series Water Heaters: Back to Basics will be a four part series discussing just the basics of Water Heater component, functions of components, and some top troubleshooting tips.  Our goal in this blog series is to inform some of our core audiences – service techs and distributors – so that whether it is a house call to service or making sure the customer gets the repair parts that are right for the job, we want to help our readers improve business, customer satisfaction, and profits through the education we offer.

Part Two

Part Two discusses Electric Heater: Thermostat & Heating Element.  Then, we shift to Gas-Fired Water Heater components: Flue, and Draft Diverter (or Hood).  Gas appliances burn gases such as natural gas or propane and therefore create exhaust. See our blog on Servicing Gas-Fired Equipment.  The Flue and Draft Diverter are the two major that exhaust these gasses in an atmospheric or blower-style gas water heater.

Electric Thermostat


Temperature sensing and control

Top Reasons for Service:

1)      Wear and tear over time

2)      Power surges or wiring issues can cause failure

Electric Heating Element

Functions: Heating

Top Reasons for Service:

1)      Sediment Build-up over time

2)      Dry fire (heater on before filled with water) can destroy elements

Main Types: B-Vent & PVC


Functions: Exit for Air Exhaust from burner.  Follow manufacturer recommendations.  Do not block.  

Top Reasons for Service:

1. If flue blocks exhaust, then hot air will get trapped in burner causing high limit switch to trip and shut off. Check for bird nests leaves and other depris that may be blocking your flue.


• B-Vent – all atmospheric vents

• PVC –  for pressurized vent (blower, power vents)

Air Current Test & Lighter used to test Draft

Draft Diverter (Hood)


Allows air flow from atmosphere to enter (or draft) into the vent. If your Water Heater has a blower on top, then you may need to test the vest pressure. For this, you will need a manometer - see our previous blog: Servicing Gas-Fired Appliances

Top Reasons for Service:

1. If flue blocks exhaust, then air will not travel in hood and up vent. This can cause the safety features inside the Water Heater to activate and shut down the heater. You want to avoid this since it requires a service call to repair.

Troubleshooting: to see if travels into hood or ‘stalls’

• lighter - exhaust will blow or suck flame in direction of flow.

• or Air Current Test Kit - more accurate than a lighter, a current tester will dispense a type of smoke to detect air currents. This tool is used by many HVAC professional and in very reliable.


Flue and Diverter solutions can be a straight forward service call for a professional plumber. Whether you are a homeowner or a professional reading this blog, please keep in mind these proper tools that can be quick solves and save the enormous time and money replacing an entire Water Heater. We don't want to go through all the headache of replacing a Water Heater just to discover that the same old blocked flue is causing issue in the new Water Heater.

Next in Part Three we be talking Gas Valve - Lighting the Pilot

For General Water Heater Maitnace tip, vist our partners at hotwater101.com - watch this video

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Kevin Parham
June 16, 2017