that's why when I call the brand's technical assistance for help in diagnosing a malfunction, they ask, -have you already checked the phase/neutral polarity GREAT explication! nice video.
Thanks Allen, On another tack, the water heater you show at the beginning and end of the video is a Vokera Aquanova LE (low emission) and those with a keen eye will notice the water pipe running through the burner upstands. That's done to cool the flame (not the heat generated by combustion) because a cooler flame reduces nitrous oxides (NoX). That is to be done to ensure compliance with recent tighter environmental legislation.
I thought I know this topic but after watching this video now I know that it was incomplete and now I fully understand, thank you Allen and vokera trainer.
Good video.. I'm pretty sure I went to a vokera training course with David Iszchak in the walsall area, got to be over 10 years ago. It was probably the best course I've ever been on. A reality nice and knowledgeable guy. If he's got any courses going on anywhere near the Birmingham area, could you please let me know. Thanks
Flame rectification is disabled when the power-supply polarity (Line-Neutral) is reversed. My combi boiler in Europe was powered through a two-pin (Schuco) plug and could be plugged-in any way round. When polarity was reversed, the PCB waited 6-seconds before shutting down due to no flame being sensed. UK plugs are wired with known polarity, but the connection to the boiler must be L to L, N to N.
That sounds a bit weird. The main circuit board power supply shouldn't care which way the mains plug goes as it converts AC to DC. The board logic in the example explained would connect the metal burner to the earth side of the "AC" rectification circuit and the rectification signal would then produce a positive DC signal to indicate flame presence. Early TV's had one AC lead connected to the chassis and this meant that it was possible for the customer to get a shock if the touched the metal chassis. All modern equipment including boilers to my knowledge use a transformer so the chassis or metal work is safe to touch
@@haroldwebster1459 To keep costs down most boilers simply convert the raw mains voltage to a lower voltage with a transformer and current limit it with resistors to make it safer and use that to pass through the flame.
Even a strong flame will only provide a very small amount of rectification, the AC isn't fully converted to DC (at best it could only ever be half wave rectified anyway as the flame acts like a single diode) so half the waveform will be very slightly rectified to DC and the other half won't. Some systems measure the difference between both halves of the wave form, others simply extract the tiny rectified portion , amplify it and if it's large enough then that is a valid flame signal. Also the electrode size thing isn't entirely correct, yes the ground electrode needs to be at least four time the size of the flame electrode but not for the reasons given, it's too complicated to explain here but there's plenty of sources, the explanation in the video is good enough for most people an even if you design flame rectification units you don't really need to know why you just need to know one needs to be bigger than the other.
Thank You for very informative vid, whats the proper metod to measure ionizating curent on boilers like Ariston Genus One, there is spark and ionizating electrode on one wire connected to PBC, second wire comes from chamber ground to pcb ground. ??? thanks in advance
Excellent explanation. I think astronomers use something similar for detecting the properties of the outer plasma shell of stars. I can't remember in what field or how it works but I think it's similar. How are you getting on in the new house? I've been in my new house for exactly a year today and I've only just arranged the painter (coming tonight) so you're hopefully better organised than I am!
i WENT TO A BOILER which failed every day at approx 5 pm. Turns out the flat it was in the polarity on the mains reversed at that time. I never did find out why this happened.
That's like the old vacuum valves the heating element causes DC current to flow one direction. A diode vacuum valve, anode, cathode. AC to DC. 😳 It's seems the pc board needs to sense a good DC voltage in order to keep the gas valve open "I think!⚠️"
Hi Allen . I'm currently studying in level 2 plumbing and want to continue after onto the Gas course. Since by 2023-2025 I heard they're stoping gas boilers in new houses. Does this mean they will stop making the gas boilers. If so wouldn't this reduce work ? Can you please explain further if possible on what's happening with these new non gas boilers etc.
2030 the cut off for gas boilers. 2025 they will prohibit gas installations within new builds. I'm pretty sure 20% hydrogen pre-mix will be combined into natural gas to help sustain the fuel itself. Plenty of work in service and maintenance after 2030. They can't abolish NG boilers and appliances just yet. Otherwise they'll create fuel poverty.
