Search waterheatertimer.org / all results
Search using Find button  

 Tweet button  
Install and troubleshoot water heater vent

flue pipe

Use 3-4" galvanized, stainless or PVC pipe.
Water heater manual will specify vent.
Side wall terminations are for power vent models.
Do not use aluminum or other low-temperature material
Assemble lower sections so they fit inside the next higher section to ensure no leakage.
Attach vent pipe sections with 3 screws.
Add vent tape to ensure no leakage.

Back to 14 things for troubleshooting water heater
13) Venting combustion byproduct
Do not use aluminum vent pipe. Use 3"-4"  steel galvanized, stainless or PVC pipe.
During water heater combustion, hydrogen content of fuel is burned, resulting in hot gases that travel upward and out the vent pipe. Obstructed vent will slow or halt combustion, resulting in tripped ECO, yellow flame instead of blue. Adequate venting or air draw up vent is required so gases vent outside.
Atmospheric vent has no blower or mechanism to assist upward flow of vent gasses. The venting action is a natural upward flow of hot air, plus the natural upward convection of air.
Power vent and flue-damper water heaters push vent by-product up the vent pipe. If blower or pressure switch or firing sequence is not functioning, the vent gasses do not travel up vent pipe.
Negative air pressure
Rusted flue pipe -or water dripping down from flue pipe:
1. Vent cover could be missing > rain water entering flue (replace cover)
2. Flue pipe clogged with bird nest or come apart or damp from improper venting: danger of odorless Carbon Monoxide poisoning


Carbon monoxide detector
Vent tape
Water heater vent hood

Simple test for proper venting: Check that pipes are not rusted or covered with white condensate. There is no water on top of tank. Burner inspection does not show excessive rusting. Steps: Turn off water heater and wait 1-2 hours for heat to stop rising from tank. Hold lit match within 1" of vent hood and see if smoke is drawn into vent. If smoke does not draw, then check for vent obstruction on roof, or call plumber.
See image of test
Vent draft test
Gas venting specs
Vent specification charts
Square footage per BTU
Ventilating tight-house/ pdf
Pilot outage and negative pressure
specs for venting-multiple-water-heaters
specs for venting-multiple-appliances
Soot on gas burner
Soot on top of heater also implies danger of improper vent and backdraft. 
Improper location of vent on roof, and incorrect clearances, or windy location can stop vent gas from leaving vent pipe. If vent gas cannot escape at top of pipe, it can be entering house at the vent hood. Soot on top of heater is evidence. If pilot goes out, the improper draft can be blowing out pilot light.
Soot on top of heater can be caused by backdraft where vent gasses are being blown back onto water heater because of shared vent pipe with furnace or other gas appliance. Read next section.
Test water heater ventBack venting or back drafting/ How to test water heater vent.
When the heater is firing, light a match next to the vent hood and see if the smoke is sucked up the vent or not.
Even if it is backdrafting, that doesn't mean you have to replace the water heater. There are other causes, including a blocked vent, or some another appliance, such as a range draft hood or clothes dryer that is pulling air down through the gas water heater vent. repeat draft test with other appliances, and vent fans operating.
Another cause can be sooty heater how to clean combustion chamber  How to clean soot from water heater
It's best to find out the cause, as it could also affect a new heater.

Water heater vent test/ pdf
Checking the draft
Gas water heater partsWater heater giving off gas smell when operating: Sooty water heater
Check for gas leak. If no gas leak, clean the flue. Check for blockage of vent (snow over the roof vent).
The flue is located in center of water heater. The flue baffle sits inside the flue and is a twisted piece of metal that can be pulled up out of water heater. This requires space above heater in order to lift flue baffle completely out.
'Flue cleaning is dirty. Use a shop vac.  Turn gas control valve to pilot.  Remove draft hood and vent pipe.  Hose out the vent pipe outdoors.  Pull baffle up and out. Rotate it in the flue, bang it around to help clean off soot which falls down onto the burner.
Take baffel outside and hose it off.  Water is good for removing soot.  Vacuum out combustion chamber. Remove burner assembly and carefully hose out the burner assembly ABOVE the main orifice.  This will clean soot out of the burner, while keeping the rest dry. Other option is to vacuum the burner in place. 

If things go a certain way, you'll look like a coal miner when finished, but heater will burn with a nice blue flame. If it does not, gas pressure is the next thing to check.'
You can casually check gas pressure by observing other appliances when several appliances are in use.
How to check gas pressure
Negative inside air pressure, Negative pressure
Backdraft Is your furnace causing water heater to malfunction? Furnace, kitchen-bath bent fans etc can affect vent draft on water heater. Called negative pressure.
Is there evidence of rusting etc on top of heater, next to the draft hood? Is the furnace room particularly cold or wet? This is evidence of backdraft.
Here is a simple, but telling test. When the water heater first fires up, a little heat will spill from the draft hood. It should only spill for a second or two under normal circumstances. So, with the furnace off, turn the temperature on your heater up to cause it to fire up (you might make a mark on the thermostat dial so it can be put back to the same place). Quickly, put the back of your hand to the draft hood to feel any heat spilling out. Count the seconds. Return the heater to normal. Now wait a bit and fire up the furnace. Feel for any spillage at the water heater draft hood with the water heater off. Count seconds. Now fire up the water heater (furnace running) and check for spillage again.
If furnace and water heater both vent into same chimney, the draft might not work properly. Water heater should have dedicated vent. For example the chimney vent pipe is is eight inch, but the two vents (from furnace and water heater) going to it are both four inch. That bigger vent might be oversized and hard to warm properly for good drafting.
If the furnace is power vent, and fan or vent will overpower natural draft. Having the furnace and water heater vents combined will cause problems. Likely the
right fix is to run two, separate three inch vents.
Water on top of heater. Rusted vent pipe. White condensate on pipes.
Inadequate draft, or improperly installed vent pipe can cause condensation inside pipe that will rust and cause white condensate.
Missing roof cap will cause water on top of heater that will rust out the water heater.

Never install more than 1 elbow on sidewall vents
Straight shot is always best shot. Elbows slow venting and cause backdraft.
Gas venting specs
Direct vent clearances
Conditions where outdoor vent is required
Vent Gas Odor
Lack of air supply
  -Clean air intake screen, open window
  Ventilating tight-house/ pdf
Improper vent
  -Read product manual for vent requirement
Poor combustion
  -Clean combustion parts, service unit
CO poisoning
If joints fall apart, or vent is improperly installed, hot gases enter home posing risk of odorless CO poisoning. Symptoms: headache that goes away when outside in fresh air. Unconsciousness.
Remove affected people from home and lay on sides, not on back. Call emergency help.
call plumber. Attach vent pipe sections with 3 screws and then cover joints with aluminum tape.

Vent tape
Carbon monoxide detector
condensate on ventCombined vent has rust and condensate.
Moisture from possible improper backdraft when either or both furnace and water heater operate.
Not enough natural draft upwards. Blocked vent.
Another vent or draft fan located inside home is pulling air down the vent.
Contaminated air supply from trace amounts of bleach, pool chemicals, process waxes, etc.

1) Check for 'spillage' or backdraft: When the water heater fires up, a little heat will spill from the draft hood for a second or two. Check spillage with water heater ON and furnace OFF. Check spillage with water heater OFF and furnace ON.  Check spillage with both ON.
2) Repeat tests with other vent fans or gas appliances operating at same time.
3) Remove all chemicals from rooms where air supply can become contaminated.
4) Reconfigure vent pipe so the 4" water heater vent entends higher into the furnace vent.
5) Sit and observe the entire cycle for several hours to help determine cause.
Attach vent hood to water heater
Install vent hood pdf from AO Smith
Flue pipe safety Flue Pipe Safety
Read manual for flue pipe clearances so hot vent pipe does not touch or come near combustibles.
Rusted flue pipe -or-water on top of gas water heater could indicate serious problem.
Call a plumber if you are uncertain.
Check pipes and flexible connectors for leaks.

If water coming from flue pipe:
1. Vent cover could be missing > rain water entering flue (replace cover)

2. Flue pipe clogged with bird nest or come apart or damp from improper venting: danger of odorless Carbon Monoxide poisoning

Serious danger from CO poisoning, a plumber should be called if you are uncertain about vent pipe water leak
Read troubleshooting at forum
Minimum distance of vent pipe from window   
Larger image with more information
Minimum distance of vent pipe from window
Side-wall vent pipe must be 4 feet away from windows and doors. And 3 feet away from inside corners.
Power direct-vent clearances
Venting a gas water heater
Conditions where outdoor air supply is needed
Power vent Venting for power vent models
Read product manual for venting specifications
Example power vent manual p17
Minimum vent distance from window
Power vent tables
Power vent troubleshoot
Typical power vent manual
Typical power vent manual2
Typical service manual
Gas venting specs
Conditions where outdoor air supply is needed
16 things needed for gas water heater & .pdf resources
What you need for operation of gas water heater.
General troubleshoot
1) Basic parts and operation
2) Adequate incoming air supply ... issues: closed doors, tightly insulated house, very hot attic.
3) Adequate air supply getting to burner... issues: dirty vent screen, dirty environment, maintenance.
4) Thermal cutoff  ... TCO ... issues: failed part, maintenance, vent.

5) Flammable vapor lockout .... issues: exposure to vapors, bad FV sensor, failed FV system,
6) Fuel supply to gas valve thermostat ... natural gas and propane are different ... issues: wrong gas, low pressure, moisture in pipe, undersized gas meter, supply line too small for BTU rating.
7) Gas valve thermostat regulates fuel supply ... issues: not enough gas, failed thermostat, failed gas control valve.

8) Fuel supply from thermostat to burner ... issues: maintenance, thermocouple-thermopile, gas control valve.
9) Clean and replace burner ... issue: periodic maintenance requires burner inspection, cleaning, and possible replacement

10) Functioning thermopile-thermocouple-pilot light ... issues: misalignment, failure of part.
11) Ignition of fuel supply by pilot light or hot surface igniter ... issues: pilot light, piezo igniter, electrode.

12) Power vent water heater troubleshoot ... issues: pressure switch, blower, blower sequence from gas control, outlet polarity
13) Venting combustion byproduct .... issues: vent in disrepair, other vents in house drawing air

14) Misc troubleshoot manuals
15) How to install gas water heater
16) How to maintain water heater
gas water heater timer Gas water heater timer
Fits Honeywell, White Rodgers, Robert Shaw
Both Propane and Natural gas models

Gas water heater timer
Gas and electric water heaters Support the economy:
Buy water heaters  from my associate links:

50 gallon Gas water heaters at Amazon
40 gallon gas water heaters at Amazon
50 gallon Electric water heaters at Amazon
40 gallon electric water heaters at Amazon
Hybrid / heat pump/ water heaters at Amazon
Heat pump water heaters at Amazon
GE 50 gallon hybrid heat pump at Amazon
Reliance 80 gallon heat pump at Amazon
Air tap: add to existing electric water heater at Amazon

How to install gas water heater
How to install electric water heater
Troubleshoot gas water heater
Troubleshoot electric water heater
Point of use water heaters
Gas and electric water heaters Buy
Electronic parts

Industrial supplies

Tools and home improvement

Home and garden

Hayward pool

Southwire electric
Barn door track
Curtain rods
Garage door parts
Shop cart
Metal table
Tork timers
Transfer switch
Smoke detector
Water detector
Carbon monoxide detector
Pool pump
AO Smith motor
box timers Resource:
Compare box timers
DPDT timers
Control water heater w/ Z-wave
Intermatic control centers Resource:
Intermatic control centers: and parts
Digital control centers and parts
Tork control centers and parts
All control centers and parts
programmable timer Resource:
Programmable timers
Countdown timers
Off delay timers
On delay timers
Timer modules
Din rail
Twin & one-shot
Low voltage power packs Recirculation systems
Enter Amazon from my links
E-mail: geno03245w@gmail.com
My response might end up in spam folder, check email folders