Hot Water Heater Dying?

legion · 10-22-2010, 05:47 AM

I bought a new hot water heater in 2004. It's one of those expensive, sealed flame units (to protect myself from myself for my own good). It's a 40 gallon unit, American Standard brand.

For the second time this week, the pilot light has gone out on the unit sometime overnight and I've woken up to a cold shower. I can restart the pilot every time.

Does this mean that I need a new hot water heater?

Is it possible just to replace the gas control unit? (Is that likely to be the problem?)

GH85Carrera · GH85Carrera's Garage

Why do you want to heat hot water?

It is likely just the therocouple.

It still heats the cold water.

sammyg2 · 10-22-2010, 06:19 AM

The tube that lets the gas out for the pilot might be dirty and not flowing as much as it should.
When you light the pilot, does the flame look as strong as usual? it it pure blue or does it have more yellow in it than normal?

rick-l · 10-22-2010, 06:24 AM

The of thermocouple may be bad or you may just have a strong breeze that blows out the pilot.

The thermocouple in the flame generates a voltage potential that causes current to flow through a coil to magnetically hold the gas valve open.

sailchef · sailchef's Garage

Check for black sooty deposits on the pilot, and make sure the thermocouple is in the flame of the pilot, it needs to stay hot to keep the gas lines open.

stomachmonkey · 10-22-2010, 07:08 AM

Quote:

Originally Posted by sailchef

......it needs to stay hot to keep the gas lines open.

Had a gas fireplace with remote start in another house. Was a PIA, when the pilot light would go out you'd have to heat the thermocouple with a BBQ lighter to get it going again.

NY65912 · 10-22-2010, 07:11 AM

Thermocouple for sure.

legion · 10-22-2010, 07:14 AM

Is this something I can replace myself?

Hugh R · 10-22-2010, 07:16 AM

Yes, unscrew it and take it with you to the Home Depot.

legion · 10-22-2010, 07:24 AM

Any hints on what it looks like? If it sits directly over the flame, it may be hard to get to on this unit...

Hugh R · 10-22-2010, 07:27 AM

Its a silver slender tube thing with a small probe end that goes in the flame, usually about 6-8 inches long. It unscrews at the gas control block and ususally unclips at the pilot.

craigster59 · craigster59's Garage

NY65912 · 07:50 AM

You'll probably have to pull off the burner with it's tubing as an assembly.

Get the correct thermocouple based on length.

Use a flare nut wrench if possible on the fitting/s going into the gas valve and do not make it up too tight.

It is pretty self evident once you pull the little door off the heater near the gas valve.

http://www.ehow.com/how_2070305_replace-gas-water-heater-thermocouple.html

http://www.youtube.com/watch?v=v0aBPsNg6vo

sammyg2 · 10-22-2010, 08:20 AM

They seal em up real tight nowadays in Kalifornia to keep guys like you and me from messing with em. It's a CARB/EPA thing. Oh, and the cost is doubled because of it.

You might be able to get in there, hard to say.

Zeke · 10-22-2010, 10:23 AM

Quote:

Originally Posted by sammyg2

They seal em up real tight nowadays in Kalifornia to keep guys like you and me from messing with em. It's a CARB/EPA thing. Oh, and the cost is doubled because of it.

You might be able to get in there, hard to say.

Is that what it is? I didn't know that. When I need a new WH, I'm going to find one on Craigslist. I've seen dozens in the past, some only a few months old.

I replaced a thermal coupler on a wall furnace last year. The part was 5 bucks and it took 5 minutes. I did take the TC to the HVAC supply for a match.

In case the TC does not fix the problem, know that a sudden drop in gas line pressure can extinguish a pilot that is not fueled enough. That could be a large furnace coming on. It would be a piping supply problem more than anything else.

But raising the flame on the WH would help.

sammyg2 · 10-22-2010, 11:24 AM

I had to replace my gas water heater last year. Gas, 40 gallon, nothing special. $525!
It used to be the gas heaters were cheaper than electric, not any more. Since when did natural gas become evil?

It's because they are a so-called low nox emitter. SCAQMD gets a percentage of every sale.

ka-ching!!!!!!!

sammyg2 · 10-22-2010, 12:22 PM

Edited - personal attack removed. -Z-man.

Evans, Marv · 10-22-2010, 01:15 PM

Probably a thermocouple but I've also seen a couple with drafty cabinets/enclosures where a blast of wind has caused a strong enough draft to blow out the pilot light. Maybe not possible on the more modern water heaters (or is it cold water heaters?).

legion · 10-22-2010, 06:52 PM

I replaced the thermocouple. For $7, I didn't even bother doing any diagnostics.

It took me about two hours to replace. One hour to buy the part, remove the gas fixture, replace the thermocouple, and realize the one I bought had left-hand threads on the part where the thermocouple interfaces with the gas control stuff, and another our to cut a channel in the old right-hand threaded part and adapt it to the new thermocouple. (As it is merely an electrical connection at that point, I wasn't concerned.)

Pilot light has been on for 8 hours without issue and several cycles of heating the water. Thank you all, this could have gotten pricey.