20 Most Recent Honeywell TH5110D1006 Focus PRO 5000 Thermostat, Digital, 1H/1C Questions & Answers

Lower temperature to lowest setting wait 1 1/2 to two min U should hear a click at thermostat & it should come on.

I can only suggest that you check and make sure all of the pins are straight and not bent over from trying to align the back plate with the back of the thermostat. Ive done it and its easy to do if you are not very carefull.

https://www.lowesprosupply.com/Catalog/Water-Heaters/Water-Heater-Parts/Gas-Valve/GAS-VALVE-FOR-AO-SMITH-WATER-HEATER-702210Looks like a good place to start. Plenty on Amazon and Ebay but I wouldn't buy them from there.

Timer setting is given of page 11 of user manual User manual Honeywell CT1501 (English - 28 pages)

replace it

Some time ago I had that happen and because of the age my repair man said it would cost too much to repair it. The problem was a worn out thermostat.

replace valve

Gas valve might be bad... The honeywell gas valve for atmospheric models is generic and can be replace without removing from heater. Following links have resources: http://waterheatertimer.org/How-to-replace-Honeywell-gas-control-valve.html http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#honeywell

try unplugging the power to the unit it should rest it

This is likely a gas valve issue. Call a repair person, it is not recommend you repair it as there is a danger of explosion.

More than likely the gas valve is defective.

Resources appear on following link: http://waterheatertimer.org/troubleshoot-gas-water-heater-thermostat.html#honeywell If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

No, the the defective valve is only on gas fireplaces and stoves, not hot water heaters.

Check the pilot is clean not a short flame so its missing the sensor. Also check flame sensor and connection .