Tacet

It's a common problems on tractors. A friend who has an agricultural machinery dealership says he doesn't sell rat poison, as there is more money to be made in repairing the wiring looms!

Like my motorcycle . There is a combined Lucas mechanical regulator and and automatic cut-out, to prevent the dynamo from motoring. The 6V system means it actually gets darker when you turn the lights on.

Good point. And if you do try it, you need to take care. I knew someone who was lucky to escape the GP without having his tail docked, then and there.🙂

This only says that the "validity of a BSS pass result" (whatever that is) can be cancelled if non-compliant alterations are made. It doesn't say that the BSS certificate is cancelled automatically without anyone knowing. And certainly doesn't say that a new BBS Certificate is required if potentially non-compliant changes are made. I can see there might be doubt and difference of opinion whether a change results in non-compliance - but surely no new BSS is required for a fully-compliant boat, even if you have moved the label showing where the battery cut-off is positioned. Any boat that passes a BSS on one occasion might well become incapable of passing another a year or so down the line. You might put some heavy metal item in the gas locker. This may mean that your fall foul of some other regulation (and/or sensible measures) but it doesn't mean the boat no longer has a valid BSS certificate. If the BSS were automatically revoked by putting a mooring spike in the gas locker - would it be automatically reinstated the moment it came out?

Once you know the meds required by your pet, it is usually possible to persuade a GP to issue a prescription by presenting with the correct symptoms/conditions. Check with Bizzard for full details. Then simply find a volunteer eligible for free prescriptions.

Wouldn't his employer sack him, if known to be telling lies? Then he would no longer be a spy.

We no longer mention the low voltage coil diversion. But, by pure coincidence, I do happen to have a spare 24V AC coil which gives the option to be used with a transformer (which, uncoincidentally, I don't have) to cut down on the effects of a mains spike. Are you saying you don't much believe in the fan creating a transient to break the coil insulation? If so, the experts seem split on this theory But it may still be worth a try? Presumably it will flatten any high voltage - it's just that you doubt that is the problem? If there is a spike, then presumably it is above 250V AC. The coil is rated, I think, to 400V although it is hoping for 230V.

Mike Cheap I like. I could possibly find the capacitor. It would be a bit of a faff as the water pipes would need disconnecting to pull out the plinth heater to the fan. But wouldn't know how to check the capacitor. Nick Sorry - I didn't even know that Transzorb was a trade name. I see your point about it shedding the current (not the voltage) to drop/clamp the voltage. Perhaps it's a bit like a syphon weir - not nano-seconds, but very quick! I would appreciate you selecting one for me. It's a 240V AC coil. Where does it belong in the circuit? A quick google suggests that one end joins the live feeding the item worthy of protection (the relay coil) and the other goes to earth. I.e. more parallel than in series. If so, presumably it must be rated as capable of passing whatever current is required to get the voltage down to the appropriate level. Not much in the case of a quick spike - but, as a principle. I quite like this as it would, perhaps more than the other fix-arounds, point the finger firmly at the spike from the fan as the problem. I could then tell my brother how clever I have been.

Nick When the clever boys refer to something as a thingy, I know I am out of my depth. Presumably a sort of weir for excess AC voltage? Too much over-tops the spillway and sends the spare volts to the bin? Mixed metaphor - perhaps sends them to neutral? Presumably the correct rating and the correct connections would be important. At the moment the fan is connected to the permanent live and operated by the pipe stat. Naturally, I have not bothered to read the fan instructions, but probably that is how it was intended. It has an option to switch the fan manually to blow cold air if required - which suggests that to me. So it is fine apart from the slightly annoying tendency to run-on when I think it ought to have stopped. But not as annoying as blown relays. Presumably any spike is arcing the pipe stat contacts (unless they have a thingy) or going somewhere harmless in much the same way as when the hoover is unplugged whilst running. MtB has suggested a relay to switch the live to the fan - which should work although there isn't much space remaining on the carefully-sized board in the airing cupboard to which all boxes and gadgets are screwed. Or I could bring back to the wiring centre a switched live from the contact side of the relay. I have a space core in the flex to the boiler/relay, so that is reasonably straightforward. But I would need to choose wisely as to just where to pick up the switched live from within the boiler. The contact side of the first-fed and troublesome relay (helpfully called Relay 3 in the diagrams) supplies Relay 2, so if the feed to the fan was taken there, I may well find Relay 2 takes up smoking. Spiking the PCB does not seem a good idea either; they are more expensive than the relays. Further down the line are the circulation pump and oil burner - both of which have motors anyway, so they seem like a better choice maybe. But I will now leave it well alone until after Christmas - unless the relay blows in the meantime! PS I have now read the fan instructions. It says it must be connected to a fused (3A) electrical spur with a switch having 3mm separation on all poles. Which it is. It doesn't include any other caveats or warnings regarding not switching the supply.

Thanks. I can be reasonably happy with that. I shall think of it as though the coiling of the wire impedes(?) a change in current - which increases the effective resistance(?) in the short-term, preventing the power from the back emf(?) from passing at relativity low voltage/high current - thus raising the voltage/decreasing the current which leads to smoke later. I probably have that completely wrong, but it will do.

Hmm. The voltage rises because the impedance of the coil is enough to stop the power getting away at a safe voltage? Again, I like this answer 'cos it means the problem has been fixed -as seems to be the case. But (I imagine) the power? from the back EMF to be very small and running off at the speed of light. ASAP, And the over-voltage current, which can't last very long, needs to be enough to fry the insulation on the coil. It just feels easier for the short blast of electrons to pass through the coil to neutral than it is for them to loiter long enough to breakdown the insulation.

Thanks! I may well be out of my depth with any explanation. I will leave it alone until either another relay goes pop or at least Christmas. The fan heater is currently(!) on a permanent live and operated by its pipestat only. It does seem to run on for quite a while - and I wonder if it somehow encourages convection in its local circuit when the three port valve is pointing toward the hot water cylinder. When I am braver, I might use an isolating relay. There is also a spare core between the wiring centre and the boiler which could be used to bring a switched live back. I just need to make sure that I take ii from somewhere that won't be upset by the spike generated by the fan.

I removed the fan (from the troublesome circuit) and replaced the relay again - and all has been well for 11 days, which is very encouraging. But I have been thinking and speaking to my techy brother. When the lines of force collapse/back EMF is created - is not the result a small amount of power but not necessarily a high voltage? If the power has nowhere else to dissipate, the voltage will rise until it is sufficient to, for example, ionise the air and jump contacts. But since the back EMF can escape to neutral through the relay coil - why will the voltage rise greatly? Doesn't it just shuffle off, uselessly through the coil at a low-ish voltage? I much prefer the fan-is-the-problem answer- but I am curious. Is anyone able to explain, simply, please?

Over 2,700 engine hours we travelled 5,700 miles i.e. an average of 2.1 miles per hour. Add the locks in, and the average is 3.7 lock miles per hour. Some hours will have been stationary battery charging - so the averages will be a bit higher. No record kept of frequency of being shouted at to slow down - probably three or four per year.

Having first boated using zinc-carbon technology, I still find the most natural units are U2s per fortnight.