Re: the thnks to Sparky617: the 12 yr old 40 gal Envirotemp gas HWT heats irregularly. Sometimes just warm somtimes too hot for thermostat setting. I assume this is a faulty thermostat. If so- can this be replaced on a gas heater.
thermostats can be replaced, relighting the pilot can be a bit of a chancy thing. check with your gas company, some insist that they do the purging and relighting for safety.
if you haven't been regularly draining a few gallons out of the tank to get sediment out, that may be the more likely cause of issues. try bleeding a bucket or two out of the drain valve carefully, until it runs clean. this is more critical on a gas heater than an electric one because there is one burner, on the bottom, with gas.
another issue can be the thermocouple that sits in the burner flame to control the thermostat with a very slight change in air pressure. thermocouples burn through, it's a wear item. provided you get the right one (take the part and serial number of the thermostat with you) and install it exactly where the old one was without kinking the line, that's a DIYable repair. a bad thermocouple shows up as no heat and the burner won't light.
but fluky temperature, I'd drain sediment first. it insulates the heat from the water.This message has been edited. Last edited by: swschrad,
sig: if this is a new economy, how come they still want my old-fashioned money?
replace thermo coupling first, then the gas control valve/t-stat
if thermo coupling does not do the trick
lowes w/h are junk, get a rheem,
you said its 12 years old, i would not pour money on it,
For general message board help, click the tab labeled "Tools," and choose "Help" from the dropdown menu.