How much to change ignition valve on water heater

There are several reasons your water heater could fail to ignite. Often, this issue is caused by the gas supply, so check to make sure your propane tank is full before you do anything else. If your gas valve or water valves are not fully opened, this could also cause the ignition to fail.

You can't. You need a new ignitor. The only way to do it would be to change to an older style gas valve with a standing pilot and a thermocouple. This would be cost prohibitive. Also, if this is a power-vented heater, you can't change to conventional pilot because the gas valve links to the control circuit for the blower. An old gas valve does not. Good luck!

If this is in a RV the propane monitoring valve may require more gas flow to turn on than the water heater requires. A central heating system requires substantial gas flow so when the monitoring valve opens to fire the central heating, there is enough gas flow to also fire the water heater.

check first if you have good water flow to and from heater. lift pressure release valve on inlet and allow few sec to flow, same with outlet hot water safety valve.

remove front cover from the heater, you should see your gas connection and thermostat knob.

check if gas is burning evenly and on whole surface, check for leaks on the heater and on the lines to and from the heater.

if you did not find any faults, no leaks, safety valves work correctly, check thermostats settings,

wind it down to minimal, then turn it to about 1/4 value (you did not specify model but this should do, widening arrow or numerical values ar self explanatory), lift hot water safety valve for few seconds, then open any hot water tap (faucet if you are an american...) and check if gas ignites and burns.

set thermostat to about 2/3 value and again, lift hot water safety valve for few seconds, then open any hot water tap. check if gas ignites and if water is sufficiently hot, if too hot - wind it down to say 1/2 way, if too cold, wind it till resistant and then back off a bit, DO NOT EVER LEAVE VALVE OR THERMOSTAT ON MAX!.

if none of these help - you need either, change the thermostat or heater itself.

if works - you solved the problem, close the tap, close the cover and use the system as you normally do.

i am always recommending use of insulation on the hot water system, it saves heaps of money over the life of the system.

hope this will help you - do not forget to vote... :-)

1) Copy following links to identify gas control valve and read ignition procedure, and access service manual for your product:
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent

2) Honeywell gas control used on recent Bradford White gas water heaters has red knob that rotates to pilot. Press and hold red knob. Then push red igniter button until status light changes.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Whirlpool water heaters are made by American-AOSmith.
Approximate age of water heater is unknown, and type of gas control valve is unknown.

Clean air intake located bottom of heater, using a feather duster.
Get more fresh air to the water heater and see if that solves problem.
http://waterheatertimer.org/images/State-select-air-intake-400.jpg

If you have piezo igniter, then check if it is putting off spark.

If there is no gas at the pilot, then gas control valve is probably bad.
http://waterheatertimer.org/pdf/How-to-replace-water-heater-gas-valve.pdf

If pilot will light but not stay lit, then change thermocouple.
Watch videos on utube to lean how to replace thermocouple.

For pilot light problems: Read information on following link:
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#pilot

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Call Bosch
Gas Products Technical Support: 800-642-3111

That model number is only shown at one website, and that model number is not shown at Bosch.
Open following link for Bosch:
http://www.boschwaterheater.com/BoschHotWatercomHome/GasProducts/tabid/331/Default.aspx
Search of Bosch for that model number shows no result.

Some water heaters do not have a pilot light. Instead they use hot surface igniter rod that glows red hot
The igniter rod ignites the gas after solenoid valve opens and gas flows to combustion chamber.
The igniter rod and heat sensor have to be operational, and have to be positioned correctly for ignition to take place.
If igniter rod is not working, or if heat sensor does not detect flame, then gas solenoid valve shuts down and water heater does not heat water.

Is there an internal sensor in the tank that tells the thermostat to call for heat. It wont call for heat until manually turned on the thermostat

it is important to turn off

the gas supply to the water heater at the manual gas shut-off

valve. This valve is typically located beside the water heater.

Note the position of the shut-off valve in the open/on position

then proceed to turn it off.

2. On the lower front of the water heater locate the combination

gas control valve/thermostat. Depress and hold

the lock tab located under the gas control knob on the right.

Rotate the gas control knob on the combination gas control

valve/thermostat clockwise until "OFF" aligns with the mark on

the front of the gas valve. Once the gas supply has been shutoff,

remove outer door. 3. Using a 1/4" nut driver or socket loosen the two screws securing

the manifold door assembly until they are free. Do not

totally remove the screws and plastic retainer washers from

the manifold door. The screws and retainer washers will be

needed to reattach the manifold door. 4. In this step, the thermocouple, manifold tube, pilot tube and

igniter wire will be disconnected from the combination gas

control valve/thermostat. Using a 7/16" wrench

disconnect the thermocouple (left-hand thread) and pilot tube

(right-hand thread). Using a 3/4" wrench disconnect the manifold

tube (right-hand thread). Carefully pull the igniter wire from

the igniter button.

5. Grasp the manifold tube and push down slightly to free the

manifold tube, pilot tube, and thermocouple from the combination

gas control valve/thermostat. when installation is complete and gas is back on, You should be able to relight the pilot and the functionality of your gas hot water heater should be restored.

Thermo coupler may be defective. it controls the main gas valve by closing main if pilot is out. make sure thermo coupler bulb is positioned over and near tip of pilot flame, but not in the flame. Thermo couplers are inexpensive and easy to change out.