MTS-10z - How do I control the 240V AC solenoid valve when switching on the blower?

Welcome.

I have an MTS-10z controller that controls the blower, pumps, CO furnace in general.
I need, along with the blower turning on, to actuate the solenoid valve, which is powered on a 240 AVC.

I was thinking of using an SSR 40 DA relay and taking advantage of the fact that the LED on the controller lights up when the blower turns on, but even though the LED doesn't light up, there is about 4.5 VDC on its legs so this solution falls through.
I wanted to use a 100-240 AVC power supply and the current itself flowing to the blower, but with the blower power control set at 20% the power supply to the blower is too low at 36 AVC

Do you have any idea how to "output" the signal from the controller or what device to use so I can control the solenoid valve via a relay?
I'm not an electronics engineer and I'm afraid to mess around with the controller itself so as not to break it.

Thank you in advance for your help with the problem.

And don't you have a flap to close the blower when it's not running? As there is a simple small low tripping force limit switch even without a relay and you have the solution. What controls this solenoid valve. Because it will close and open frequently?

The idea is there to some extent, but the flap may jam and the limit switch will not work, an uncertain solution for me.
The solenoid valve is supposed to open when the blower is running, i.e. the furnace is running.
In the same way, during standby, every now and then the furnace blows and at this time the valve is also supposed to open to give a dose of fuel.....d to maintain the flame.

Problem solved.
I used a phone charger to charge the phone.
It has low power consumption and does not interfere with the controller.