FishWish 1,530 Posted February 16, 2014 I just opened a new Fluval M100 heater last night…stuck it in the tank and plugged it in. The blue pilot light lit up and I went to bed. This morning the water is still cold…pilot light is out and heater is set 72*. I took heater out of it's holder and pilot light turned by on…secured heater and light stayed on for about 20 min. Now it is out again. Is there a trick to this? Do I need to add warm water to get it near 72 then the heater will take over? 0 Quote Share this post Link to post Share on other sites
HomerJay 4,668 Posted February 16, 2014 I am not sure how your heater works, but usually the light is only on when the heater is on. If the water is at 72, the light will be off until the temp drops below 72 and then it will turn on while heating. Do you have a thermometer to verify your water temp? 0 Quote Share this post Link to post Share on other sites
fantailfan1 26,742 Posted February 16, 2014 (edited) What temp is the water? The light is usually only on when it's heating then turns off. Edit: HomerJay beat me to it. Edited February 16, 2014 by fantailfan1 0 Quote Share this post Link to post Share on other sites
GoldenSpoiledRotten 6,786 Posted February 16, 2014 The heater only turns on when it senses that the water is cooling. The light isn't going to stay on. Have you checked the temp? 72 degrees usually feels cool to the touch for me too. 0 Quote Share this post Link to post Share on other sites
FishWish 1,530 Posted February 16, 2014 Oh sorry, thermometer says 66* but I don't have an airstone by the heater to disperse the heat. I'm going to try that. 0 Quote Share this post Link to post Share on other sites
Mikey 6,780 Posted February 16, 2014 What kind of thermometer do you have? 0 Quote Share this post Link to post Share on other sites
jmetzger72 6,976 Posted February 16, 2014 (edited) Did you let the heater acclimate for the time period suggested in the directions before you plugged it in? This helps set the heater thermostat. If not, try unplugging it, let it cool in the tank, then pull it out for about 20 minutues. Then put it back in the tank (unplugged). Let it sit (unplugged) in the tank for about 20 minutes. Then plug it it in and wait for about 24 hours for it to get the tank to the desired temperature. I have several Fluval heaters and they usually work great. If this procedure doesn't work, I would return the heater. Edited February 16, 2014 by jmetzger72 0 Quote Share this post Link to post Share on other sites
fingers 1,350 Posted February 16, 2014 (edited) I am sure the instructions for my heater say the light comes on when the heating element is ON!! I would try turning it up slightly as you can't rely on the settings on the dial. it is really trial and error! also is the heater powerful enough for the water volume of your tankAlso the light will go on and off as the thermostat comes on and off to maintain an even temperature!! Edited February 17, 2014 by dnalex changed OFF to ON :) 0 Quote Share this post Link to post Share on other sites
fingers 1,350 Posted February 16, 2014 (edited) I am sure the instructions for my heater say the light comes on when the heating element is OFF! I would try turning it up slightly as you can't rely on the settings on the dial. it is really trial and error! also is the heater powerful enough for the water volume of your tank Also the light will go on and off as the thermostat comes on and off to maintain an even temperature!! Sorry that should read light on heater on!! Edited February 16, 2014 by fingers 0 Quote Share this post Link to post Share on other sites
Justin 383 Posted February 16, 2014 You have gotten a lot of great advice! I would also suggest that you check the instructions to make sure there wasn't an extra step you missed! Good luck 0 Quote Share this post Link to post Share on other sites
FishWish 1,530 Posted February 16, 2014 Did you let the heater acclimate for the time period suggested in the directions before you plugged it in? This helps set the heater thermostat. If not, try unplugging it, let it cool in the tank, then pull it out for about 20 minutues. Then put it back in the tank (unplugged). Let it sit (unplugged) in the tank for about 20 minutes. Then plug it it in and wait for about 24 hours for it to get the tank to the desired temperature. I have several Fluval heaters and they usually work great. If this procedure doesn't work, I would return the heater. Everything seems to be working now. Maybe I was just being impatient. Go figure. I should have read the directions more thoroughly. It's holding steady at 70 deg now with the dial set at 72. I can live with that. Thanks for the help! Sent from my iPhone using Tapatalk 0 Quote Share this post Link to post Share on other sites
DieselPlower 2,123 Posted February 16, 2014 I just want to point out that there is no "pilot light" in an aquarium heater, like there may be a pilot light on a stove, furnace, or water heater. Those things are often powered by natural gas whereas the aquarium heater is obviously electric and no pilot light us required. 0 Quote Share this post Link to post Share on other sites
FishWish 1,530 Posted February 16, 2014 I just want to point out that there is no "pilot light" in an aquarium heater, like there may be a pilot light on a stove, furnace, or water heater. Those things are often powered by natural gas whereas the aquarium heater is obviously electric and no pilot light us required. I am with you on that. I should have refered to it as a "cool blue indicator lamp" like it says on the back of the package but I got distracted by the directions that say..."the unit only heats when the pilot light is illuminated". I blame Fluval!! Sent from my iPhone using Tapatalk 0 Quote Share this post Link to post Share on other sites
fantailfan1 26,742 Posted February 16, 2014 The cool blue indicator lamp, of course. And I've been referring to it as the on/off light. Silly me. 0 Quote Share this post Link to post Share on other sites
DieselPlower 2,123 Posted February 17, 2014 alright well, if the package says pilot light might as well call it a pilot light! 0 Quote Share this post Link to post Share on other sites
dnalex 13,633 Posted February 17, 2014 And now I shall pilot us to a derailment... :rofl I'm glad everything worked out, Erin! 0 Quote Share this post Link to post Share on other sites
sandybottom 56 Posted February 17, 2014 for tanks up to 30 gallons.if your tank is larger it may struggle to keep up the temp. 0 Quote Share this post Link to post Share on other sites
fantailfan1 26,742 Posted February 18, 2014 It's a 20 long I believe. 0 Quote Share this post Link to post Share on other sites
FishWish 1,530 Posted February 19, 2014 Yes! 20 long. I think I will eventually have to unplug and recalibrate. Everything is working fine but my thermometer reads about 2 degrees below what the heater is set on. Sent from my iPhone using Tapatalk 0 Quote Share this post Link to post Share on other sites
Justin 383 Posted February 19, 2014 Yes! 20 long. I think I will eventually have to unplug and recalibrate. Everything is working fine but my thermometer reads about 2 degrees below what the heater is set on. Sent from my iPhone using Tapatalk What type of thermometer do you have? 0 Quote Share this post Link to post Share on other sites
sonny.barile 111 Posted February 19, 2014 Make sure that it was not failing to operate because of a short in the wire. 0 Quote Share this post Link to post Share on other sites
FishWish 1,530 Posted February 19, 2014 Make sure that it was not failing to operate because of a short in the wire. How would I check for a short? Justin, it's the standard mercury looking thermometer from petsmart. Sent from my iPhone using Tapatalk 0 Quote Share this post Link to post Share on other sites
jmetzger72 6,976 Posted February 19, 2014 (edited) Yes! 20 long. I think I will eventually have to unplug and recalibrate. Everything is working fine but my thermometer reads about 2 degrees below what the heater is set on. Sent from my iPhone using Tapatalk I think that is fine if it consistent. Set the heater up 2 more degrees and see if the thermometer also goes up 2 degrees. So, for example, if you want your tank at 72, you might need to set your heater to 74. Edited February 19, 2014 by jmetzger72 0 Quote Share this post Link to post Share on other sites
sonny.barile 111 Posted February 19, 2014 See if it turns on and off by gently wiggling it so the wire moves. It probably isnt shorted but I got worried when you said it turned on when you moved it in it's holder. 0 Quote Share this post Link to post Share on other sites
jmetzger72 6,976 Posted February 19, 2014 My Fluval heater lights always turn on for a second when I move them. 0 Quote Share this post Link to post Share on other sites
