Our RWB9 oil heater says lockout and is nt working

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Turn it off at the black toggle switch inside the front panel or turn it off at the breaker for 2-3 minutes
Then try again.
Check that flow is good, gas is on ect...
Is it saying lockout on the display?
If not then as you fire it up after cutting power keep the panel off and watch the ignition control red diagnostic light.
The blinking sequence of that light should point you in the right direction. There is typically a label that will tell you what the blinks mean.
Minimax nt heaters are on borrowed time, and in most my Delong with them once they start having an issue it will never end , basically they are lemons and replacements for them is very common

Push and hold the button for 60 seconds. It is in customer lockout because it was pressed more then 3 times.

Hold button for about a Minute.

Check the c/heating pump

For some reason the ignition is not working or there is a gas supply issue. Best get a tech out to check it, these heaters are tricky.

The British Gas UP1L is a Siemens RWB9 programmer that has been rebranded. The instruction manual can be found here: http://www.kaizenenergy.ie/wp-content/uploads/2016/11/Siemens-RWB9-Programmer2.pdf

FIRST ... CHECK YOUR FILTER !! IT MUST BE CLEAN ! THERE IS A PRESSURE SWITCH ON THE HEATER WATER INPUT LINE . IT MAY NEED TO BE REPLACED .. JAY.. THE POOL PUMP REPAIR GUY IN LONGWOOD FLORIDA

Press down and hold the reset button. You may need to bleed the oil line once you get oil in the tank.

sounds like overheat stat easy job to replace and do,nt cost the earth best of kuck