Need help decoding some diode (zener) and

[Houseman]

Hi folks.
I have dismantled in my cellar a circuit that controls hot water fluid through a solenoid valve, driven by electronics using PHASE-CUT method at 24V AC 10W controlled by 0-10V DC input
I have discovered that such method was used in the 90's to efficiently control solenoid valves now it is supeseded by way more efficient PWM method.
The PCB got magic smoke and since there are no more spare parts available I need to repair it by myself rather than changing the entire valve that costs more than 2k..
I want to study this circuit so I have reversed some part of it but I need some help to discover parts of the electronic.
In the attachment you can see a black element (must be a capacitor labelled ERD 0,033 J - maybe a 33 pF ceramic capacitor? - my LCR tester cannot recognize it) and C1 a color coded ceramic capacitor that could be 27pF. correct me please if I am wrong.
I am having troubles with the DIODES. Obviously all the components has been desoldered and tested separately. The picture is for reference only.
One tester I have erroneously says they are all zener diodes all 8,7V. Could be maybe D9 ( blue color coded) since it has anode to ground and the cathode is connected in parallel to the electrolytic capacitor you can partially see top left. But what about the D14 green one?
Another component tester says they are all normal diode with forward voltage of 0,7V and does not detect any reverse voltage of the zener.. maybe D10-D13-D15-D16 could be normal 1N4001.. I do not know how to find out.
Could you please help decode the ring code? I have searched through the forum and found other threads but I guarantee there are no other rings nor letters on it. also by a microscope.
Thanks a lot.
Regards.
Steve