I have a relay in my boiler which buzzes/arcs I'm trying to diagnose
the fault, probably in my wiring. What conditions (eg shorting) would
cause a relay to switch on & off very rapidly (leading to a buzzing.
noise) & arc?
All the thermostats/motorized valves function correctly. The
condition occurs when the DHW reaches temperature, ie the cylinder
Can't work it out. Any advice would be appreciated.
Can't be specific, but it sounds as though your relay contacts are in series
with the relay coil, i.e. when it starts to operate it disconnects the
operate path and then releases, then operates, ad infinitum...
What sort of a system is it?
Y or S plan I assume.
If it is a Y plan then I would be tempted to blame the cylinder stat. It
sounds like that it its contacts have failed.
On a S plan I would suggest the microswitch in the HW valve has failed
On Fri, 27 Jan 2006 22:03:03 +0000, firstname.lastname@example.org
Thanks- I'll investigate this.
I'll have to sweat over the circuit diags for this- I've taken the
correct terminals on the boiler out to the controls. Superficially, I
can't see how this could then get swapped over to mix the contacts &
power supply for the coil.
Would this condition be true when the cylinder stat is satisfied
(break on temp rise), the arcing starts. It is definitely arcing - I
can see it. I tried disconnecting the cyl stat & the relay
immediately started arcing. If I up the temp on the cyl stat, the
arcing stops.Some of the circuitry is hard wired in the boiler (system
boiler) so it is not easy to work out what goes where. I've also got
a programmable room stat on the same control circuit.
I must admit, I had to think long & hard about marrying the circuit
diags for the boiler, the motorised valve & the prog & cyl stats.
I wondered about the following diagnostic approach: presumably if I
disconnected all the external controls, (valve, 2 stats) and used the
unused boiler simple time clock in it's ready-wired configuration (I
had to remove a loop to "break into" this control circuit), this would
indicate if the fault lay in the relay, or my wiring? A nod would be
appreciated, as this is a fair amount of work....
It is S plan. This is a possibility Iwould look at later as all new
components. Chap at PTS assured me :*) that PTS Boss brand
motorised valves made by Danfoss (or other big name) so I suspect my
wiring first (more likely that I've wired the valve wrong), or I have
a hunch about the relay.
Probably help to mention that this condition started from first use.
Corgi chap did the gas stuff & test fired it - all OK, but obviously
didn't hang around for ages until the water got to temp. All new
components in CH system.
BTW, what is the correct way to get 6 or more cable cores/conductors
from a boiler in one room to controls in another? The most cored
cable I could find was 5. In the end I ran 3 lots of T&E & labelled
the conductors at each end 1-6. Is that bad?
If I had the cash I would get someone to look at it.
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