so I moved into a new apartment last month. The water wasn't very hot so we thought it was just because the weather has been getting cold. Turns out the water heater has only been on pilot, so the water wasn't getting hot. Does this mean that the water heater was leaking case because the water was only luke warm? We didn't smell any gas.

  • Was there a pilot flame burning? If there was, it would burn up all the gas, so no leak. Most modern heaters use a thermocouple to sense the pilot flame, and shut off the gas if there isn't one. So again, no leak.
    – Tester101
    Nov 19, 2015 at 23:50
  • I think it was since the water was warm but not hot. Also, it's a brand new water heater since the apartment has been renovated. And its been like this for a month and we didn't notice the smell of gas.
    – AzureWorld
    Nov 20, 2015 at 0:45

2 Answers 2


Many gas appliances have a "Pilot mode" where they will just burn a pilot light, and ignore the thermostat setting. Typically a 3-position control reading "Off-Pilot-On" and it sounds like yours is probably of that type and was in "pilot."

Turning this into a hunt for a gas leak is just plain illogical.

Almost certainly what the tech flipped from "Pilot" to "on" (and was internally laughing all the way to the bank about.)

Gas valve with thermostat

Gas control black Gas control red

  • This sounds like what happened. He did something and then the water header made a loud sound. like a ignition soun and it started working
    – AzureWorld
    Nov 20, 2015 at 3:56

If the water heater has a simple mode to just maintain the pilot flame it should be as simple as putting the water control into active heating control mode.

It is possible that the temperature control knob on the water heater was simply turned down to its very lowest setting.

  • It seems more likely that the thermostat was turned down because a pilot light won't generate much heat. It is about the size of a candle.
    – user19474
    Nov 19, 2015 at 23:39
  • It was on the lowest setting before. We turned it up to very high last night but it was still lukewarm. We call in a techinician and they said that the water heater was on pilot before and he just switched it on. Just more worried that this might have leaked a little gas even though we didn't smell it or anything for the past month. yeah the water was not very warm but it was also not cold.
    – AzureWorld
    Nov 19, 2015 at 23:41
  • pilot is how you start a gas appliance when the thercouple probe is cold then after 30 seconds to run, it should have started burning once it was turned up, if not there is usually a temp setting make sure the gas valve and thermostat are turned up, land loards regulary turn them down to save $ on empty houses I would worry about a tech that jumped right to a gas leak, it will take an hour or 2 to get hot from a cold tank depending on the units recovery rate
    – Ed Beal
    Nov 19, 2015 at 23:46
  • Yeah, it turned on right when the tech was there. He didn't say anything about a gas leak but I'm just wondering if it was. I just took a shower and the water was hot from what it was before which was lukewarm. Does that mean that the pilot was on but gas wasn't running through it? We turned the thermostat to high yesterday and it was still lukewarm
    – AzureWorld
    Nov 19, 2015 at 23:58
  • it is possible it is full of sediment if it did not recover since yesterday , I I missed it was hot today it takes time to recover,,,so if it was good today everything is probably fine...no real chance of a gas leak I thought he suggested it,,, just a thought will the thermostat go further than high? most units will go to ~180 or so at max temp dont want to go higher than that, water causes burns ~130 but we usually set the temp higher so the hot mixed with cold will last longer
    – Ed Beal
    Nov 20, 2015 at 0:05

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