Kitchen Gas Appliances - Gas water heater w/ power vent
Doityourself.com community forum was created to provide answers to all questions related to home improvement and home repair. Doityourself community can help you find information about how-to topics on small fixes to large remodeling projects. With comprehensive how-to content and expertly moderated community forums DoItYourself.com makes it easy to tackle even the most complex home improvement projects.View Full Version : Gas water heater w/ power vent
sorrelmb
01-31-01, 08:50 AM
I have a 6 year-old residential 50 gal. gas water heater with a power vent installed. Since my shop is in the basement I can observe the cycling pattern of the heater. Recently we have noticed an apparent decrease in quantity of hot water available in the mornings (after an overnight "idle" period). The unit responds to a demand for hot water by igniting and heating until the temperature limit shuts the unit down. Flame appears fine. When the unit subsequently attempts to heat to maintain the water tmeperature in the tank (while no hot water is being demanded), ignition does not take place. Here is what happens. The power vent energizes and the unit attempts to ingnite but fails and shuts down. If I open a hot water tap and wait sufficient time, the unit will ignite and heat as described earlier. This short cycling has started w/i the last 6 months and is constant as long as no hot water is demanded. Any ideas?
Sharp Advice
01-31-01, 08:59 PM
Hi:sorrelmb
Kindly explain what you mean by "power vent?"
Does this tank have a motor driven vent dampener?
Or does it have a forced draft fan motor?
Based solely on the tanks gallon capacity, I think you mean a motor driven vent dampener that rotates open when the water needs to be heated and closes when the water heating cycle completes.
Often times the terminology of words used to discribe a part varies and is then left open to interpretations.
Example: Thermocouple.
Thermocouple is the correct word but often times the word thermocoupler is used. There isn't any part used on a water heater, furnace, etc. called a thermocoupler.
Therefore, kindly explain what you mean and I shall attempt to help you further. You may want to post this question in the heating and cooling forum too. Ask the plummber also.
Kindly explain what you mean by "power vent?"
Does this tank have a motor driven vent dampener?
Or does it have a forced draft fan motor?
Based solely on the tanks gallon capacity, I think you mean a motor driven vent dampener that rotates open when the water needs to be heated and closes when the water heating cycle completes.
Often times the terminology of words used to discribe a part varies and is then left open to interpretations.
Example: Thermocouple.
Thermocouple is the correct word but often times the word thermocoupler is used. There isn't any part used on a water heater, furnace, etc. called a thermocoupler.
Therefore, kindly explain what you mean and I shall attempt to help you further. You may want to post this question in the heating and cooling forum too. Ask the plummber also.
sorrelmb
02-01-01, 06:16 AM
Power-vent is a squirrel cage fan located at heater exhaust (top of tank). This fan is in the exhaust line and is energized prior to ignition to force CO out through the exhaust vent.
Sharp Advice
02-01-01, 03:14 PM
Hi:sorrelmb
Thanks for the added information, helps.
During the cycle that fails, as you clearly and well discribed, I would suspect either the central computer/control module isn't getting a signal from the dampener vents position sensor or fans in operation mode sensor and correctly reacting to it.
If the control module fails to get the signal, react to it or process it correctly, it will default to fail safe and shut down the start-up cycle before it even begins.
An excellent safety system in total design and working functions that works very well---when it works correctly!
The testing proceedures are much too lenghty and difficult to explain in a forum such as this. I haven't actually done this proceedure in two years either, to be completely honest here.
However, during an automatic relite cycle to maintain internal water temperature, if possible, see if you can notice anything happening differently then that which happens when cold incoming water enters the tank. Could be a componet failure with in the thermostat and any sensor from to another part.
Thanks for the added information, helps.
During the cycle that fails, as you clearly and well discribed, I would suspect either the central computer/control module isn't getting a signal from the dampener vents position sensor or fans in operation mode sensor and correctly reacting to it.
If the control module fails to get the signal, react to it or process it correctly, it will default to fail safe and shut down the start-up cycle before it even begins.
An excellent safety system in total design and working functions that works very well---when it works correctly!
The testing proceedures are much too lenghty and difficult to explain in a forum such as this. I haven't actually done this proceedure in two years either, to be completely honest here.
However, during an automatic relite cycle to maintain internal water temperature, if possible, see if you can notice anything happening differently then that which happens when cold incoming water enters the tank. Could be a componet failure with in the thermostat and any sensor from to another part.