Suburban SW6DE slow ignition

It's not dirty, it's new, but I have checked it anyway.
There is only flame shooting out during the initial startup. It burns correctly when running after startup.

Thanks

Angus_NB wrote:
It's more than a poof but less than a bang. :)
Flame comes out about 8" from the cover.

It's the same every time, even while connected to shore power.

This is not installed in my 3 year old trailer.

I'll check the electrode.

Flame comes out from cover.....

Combustion/exhaust chamber obstructed.......mud dabbers nest or even spider webs. Run a wire thru then tie rag on end and pull rag back thru

Burner tube not aligned with gas valve. Propane is low pressure and needs to flow down center of tube to properly mix with air
If propane bounces down sides of burner tube it will not mix and be fuel rich

Orifice......needs to be clean/clear
Unscrew from gas valve and soak in alcohol then blow out with air

It's more than a poof but less than a bang. :)
Flame comes out about 8" from the cover.

It's the same every time, even while connected to shore power.

This is not installed in my 3 year old trailer.

I'll check the electrode.

As a repairman, I sometimes see the spark jumping from the ceramic portion of the igniter to metal and not across the electrode to the to ground rod. This results in the mini explosion you describe. You can go out and watch it light if have someone else turn the switch on. It is easier to see this if you do it later in the evening near dusk or place something like a ball cap over the igniter area to block the sunlight during the test. It may light properly 2-3 times and then spark in the wrong location.

Is this a "poof" or a real explosion (bang).
A poof is quite normal.

As you can see by chart posted....12.3V is lowest one should allow battery voltage

11V is killing battery

WHY does a 3 yr old RV have a NEW water heater?

The unit is new so has never received maintenance.

I understand that 11 volts is low, my battery is never lower than 11 volts and is usually above 12.
Suburban shows 10.9 volts as the lowest operating voltage.

When you turn propane switch ON the spark electrode should start sparking within 15 seconds
While sparking DC voltage is sent to gas valve solenoids opening gas valve.
DC Voltage is only applied during this ignition sequence for 6-8 seconds.

Spark electrode should be directly engulfed in main flame when it lights off and should have a spark gap of 1/8"

Your DC voltage of 11V is way LOW (drained battery voltage)..........s/b 12.2V at minimum.
IF that voltage is measured at batteries then batteries are if dire need of recharging........load testing

If that voltage is measured at water heater...then your connections/contacts are dirty/loose/corroded and need cleaned/tightened

When was the last time it received basic maintenance like cleaning the burner and flue?