To quote you, "Note that if running the boiler from the genny you will probably need to make sure that earthing is correctly connected for the flame sensing to work properly. So basically set the genny up with an earth spike like a TT system, and tie one leg of its output to the earth."
Well, that turned out to apply in the case of my boiler, but why? Can you explain it slowly and simply? Why does the flame sensing need this?
Bill
Dunno exactly - it's something to do with flame ionisation rectifying the signal or something.
Also, as far as I can see on my 2 boilers, the return path for the spark is via the casing, so if this isn't connected to one side of the supply
- preferably the neutral(!) - there's no conductivity. Similar, I suppose, to a car engine - where the engine casting needs to be connected to the -ve side of the battery for the spark plugs (and other electrics) to work.
Yes, it effectively rus between live and earth (far too small a current to trip an RCD though).
I can confirm this having had to reverse engineer the Potterton Netaheat board to fault find. Feeds live through .001uf capacitor and 1M resistor into the flame and looks for a DC component. Presumably would not work if L & N were reversed at the supply.
Chris K
I knew about this anomaly, but only through reading this group.
This thread reminds me that I don't think I've seen anything from Geoff. A search on my newsbase looks like last posting was 16th May, unless he's changed his alias and I've missed it?
I don't know much about boilers, but it sounds like the boiler, or this par ticular component of it, doesn't like floating earth generators. In the sam e way that many caravanners found out that their generator keeps tripping o ut the RCD, until tie the earth down.
No, I called in in August to pick up a pcb, a busy personal and business life, and why spend time reading this group with the amount of idiots and trolls here, so he doesnt bother much/ at all now.
What the excellent posts above said really ;-)
I'm finding it hard to understand why that might happen, a floating generator would look like a supply from an isolating transformer.
In message , Andrew Gabriel writes
No I've not seen any posts from him either. Though did notice a post from what I think was him on an DIY forum recently
I wondered about the RCD aspect. What's the current?
Bill
Bill
In article , Andrew Gabriel writes
Not entirely convinced on this one, my boiler runs on a transformer isolated supply and I assume the spark generator/flame sense circuitry does the same so I'm not sure why the earthing or supply polarity is so important.
low fractions of a mA...
He is alive and well but up to his ears in expanding his empire into an adjacent unit.
Ah. I see.
Bill
You could try temporarily disconnecting the boiler's earth wire, and then see whether it still works.
"Re: John Rumm on boilers"
On 10/12/2013 00:37, Bill Wright wrote
How dissapointing.
I'd hoped to be reading about your exploits with er, differently-attactive women.
I had my tales all ready to tell, but perhaps for another day :-)
Have something to add? Share your thoughts — no account required.
Ask the community — no account required