Hi,
I was wondering if anyone could tell me a little about boiler interlocks?

I'm into my second year at college (level 2) and am interested in the heating side. At first I thought a boiler interlock was a wiring box but now I know it's a connection between the boiler controls. Trouble is I'm struggling to picture how they are wired.
For example:
I have a diagram that shows the cylinder stat and the heating stat being wired to a three port motorized valve (Y plan). Then it shows that the two stats also have a wire to the programmer. Then there is a wire from the motorised valve to the pump and a wire from the pump to the boiler. It made sense that a stat calls for heat, checks with the programmer, and opens the motorised valve which in turn tells the pump to run and the boiler to fire up. I realise that the stats then turn these devices off when they are up to temperature.

Trouble is, My dad had a plumber in to upgrade his boiler and programmer and I borrowed the manuals to have a look. The boiler manual (glowworm condensing boiler) has a connection for the positive of the room stat from the programmer but no connector labeled for the cylinder stat. The programmer had a connector for the cylinder stat but not for the room stat. How do both stats talk to the boiler to ask for heat.

Is it that different boiler manufacturers require different wiring to create an 'interlock'.

I know I'm only a scrote from college but if anyone could at least explain the basics of how a modern setup would look I'll be made up.

I assume the wiring for an S plan uses a similar principle.

Thanks for any info.

Mark

Interlocks are some devices or connection system which prevents hazardous conditions in any industrial equipment.
For boiler, there r many interlocks...
1.purge interlock-it prevents fuel from being admitted into an unfired furnace...
2.fan interlock-fuel is shut off on loss of air flow
3.low fuel supply interlock- fuel is shut off upon loss of fuel suply
4.loss of flame interlock-all fuel is shut off upon loss of flame in furnace
5.fan interlock-it stops forced draft upon loss of induced draft fan
6.low water interlock
7.high combustible interlock

As per boiler manufacturer they have their different design and parameters but some interlocks I am describing you may be useful for you:
Firstly with ID fan
Furnace press in positive side
Drum level
Dearater level low- low than BFP tripped and than boiler tripped.
With some drrives Yhanks