On 10/02/2018 18:10, TheChief wrote:
Roger Mills Wrote in message:
On 10/02/2018 17:15, TheChief wrote:
Hi all
Struggling to get to the bottom of this one!
The boiler is Worcester Bosch 24ri system, not combi.
The controls are Honeywell 2 heating zones and cylinder zone.
The boiler is not showing error lights i.e. the blue indicator
light is constant, not flashing.
The Honeywell stats are wireless but seem ok.
When I up the stat temperature for either upstairs or downstairs
heating, the base unit indicator light led illuminates and the
appropriate motorised valve opens. I have had the covers off
both and can either see or hear the click of the microswitch. I
would be surprised if both had failed along with the hot water
zone at the same time.
Anyone know why my boiler isn't firing?
Background...... Air seems to be affecting the upstairs rads, but
they are reluctant to bleed despite standing water in the header
tank. I turned the boiler off before all this as I was adjusting
the auto bypass valve which sticks occasionally and causes
pressure surges.
Any comments or assistance appreciated.
Phil
Does the boiler fire when there's a demand to heat the hot water
cylinder? If it DOES, it suggests that the microswitches in the heating
zone valves are not working, even though they appear to be.
If the HW doesn't work either, it's either a wiring fault or a boiler fault.
Have you got a multi-meter that's suitable for mains use? If so, you
need to trace where power is present, and not present. [I wouldn't trust
a neon screwdriver for that - they can give misleading results]
if you have a conventional S+ Plan system, the micro-switches in the 3
zone valves will all be wired in parallel, with their grey wires
connected to terminal 1 in the junction box and their orange wires to
terminal 10.
When one or more zones is calling for heat, terminal 10 should be live.
If it isn't but terminal 1 is, either no valves are open (their manual
levers will move freely when they are open) or the micro-switches are
not working - or a wire has become disconnected.
If terminal 10 IS live but the boiler still doesn't fire, you need to
trace the connection between this and the switched live on the boiler.
If power is getting to the boiler, there's a problem with the boiler. If
it's not, there's a problem with the wiring. As well as tracing the live
wires, make sure than no neutrals have accidentally become discounnected.
--
Cheers,
Roger
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Thanks Roger
Any chance this could be down to an air lock and overheating?
Lack of circulation or a HX full of air will usually cause a over temp
lockout, however it would not stop it firing in the first place usually
- at least when the boiler is cold and has been freshly power cycled.
Is the pump controlled from the boiler, or it it wired up to the wiring
centre?
If its on the wiring centre, then it will typically be driven by the
same call for heat that goes to the boiler. In that case it would
suggest the call for heat is going to the boiler, but not much else.
That still points to the boiler itself being the problem though.
If the pump is run directly by the boiler, and it spins up that also
suggests a boiler fault, but does give you a bit of extra information,
since it suggests the boiler is seeing and responding to the demand, and
attempting to fire before failing at some point of its proving cycle
(something like not getting a tell back from the air pressure switch, or
flame detection failing)
As noted in my reply to Harry, I got the boiler to run v briefly
and this produced a fast flash error light
The installation states that this indicates a volatile lock out
(sensor fan or code plug). No idea what a code plug
is.
--
Cheers,
John.
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