fan is spinning, pump seems to be running, have continuity across flow switch
just tested that, ok
Well there's not much more to test . but check the he and CH thermistors. As when these go , sometimes you get weird outcomes . look for a big change in ohms upon temperature change
Also check the water pressure switch is making and even though pressure may be right it could be blocked .
Have to come offline now . early start.
We can continue tomorrow if you like
im sure i've checked all the common sense stuff. this problem has occurred periodically for a while ( like once every few months ) and every time ive got it looked at the bloody thing starts, but not this time