That is a complete misconception. The reason you hold in the button is
to allow the thermocouple time to get hot enough to provide the
electricity needed to keep the safety valve open when you let go of it.
It has nothing to do with the flue. Many propane devices with manual
safety buttons work this way, even ones without flues or sealed burn
chambers.

The safety valve is an electromagnetic valve with a manual set. You push
in the button and if the thermocouple is providing enough electricity to
the electromagnet the electromagnet with overcome the small spring that
would otherwise close the valve when you release the button. If the
flame goes out, the thermocouple cools down and stops providing
electricity. Then the electromagnet turns off and the spring closes the
valve, turning off the gas to the burner.

The electricity provided by the thermocouple is also what is used to
trigger the flame LED on the Westy panel.

Mark

Kim Brennan wrote:

> ...............
> There really aren't many things that can go wrong with the system. You
> do need a positive draft on the flue (i.e. hot exhaust should be going
> out the exhaust, which causes fresh air to come in via the fresh air
> side of the flue.) That's what holding in the button for a couple of
> minutes is supposed to be help set up.