Trouble with Apollo Hydroheat gas water heater

[scf]

I have an Apollo Hydroheat gas water heater, part number A650N, which was manufactured in 2004. I have had the same issue for the past three years. For some reason the water heater shuts off. If I manually throw the on/off switch the heater will work for a day or two and then fail again.

I have had the unit "repaired" several times. The repair consists of the tech cleaning the burner unit. The last tech said that I had a faulty flame sensor and it needed to be replaced. But when I go on-line and look at the schematics I do not see a flame sensor.

Any suggestions.

[rkenney]

Why don't you post the schematic you're referring too.

Most schematics will call it a thermocouple but flame sensor is an accurate description of what it does.

It is heated by the pilot flame and allows the gas to come on for heating the water. In the absence of a pilot (blows out) you wouldn't want the gas to come on. If the thermocouple is bad the gas will not come on whether you have a pilot or not.

[Jim Katen]

Thermocouples don't usually fail intermittently over a period of three years.

My guess is that something is causing the pilot to blow out. Look at the configuration of the flue.

[inspector57]

Agreed, something blowing out the pilot. Check both the flue and the combustion air provisions.

[Brandon Whitmore]

Anyone have a picture of this water heater burner/ pilot configuration? I'm trying to picture it, but can't right now...