Boiler repressurise? Or how to reset a Worcester Bosch boiler??

[mickle]

Cool.

Gas turbine control systems eh?. Would you say that L4S is a "momentary" logic signal which will go to a logic "1" when a unit START is initiated and all the start permissives, including sufficient L.O. pressure, have been satisfied. L4T is the logic signal which will be a logic "1" when any trip (emergency shutdown) condition is detected by the sequencing or application code, such as low-low L.O. pressure, or high-high vibration, or exhaust overtemperature. L94T is the logic signal which will be a logic "1" when a normal, automatic non-emergency shutdown is active and the unit reaches the point at which the fuel is to be shut off. In order for L4 to be energized (go to a logic "1"), L4T must NOT be a logic "1" (meaning there must be no active trip conditions detected), L94T must NOT be a logic "1" (meaning that a normal shutdown is not active and fuel does not need to be shut off), and L4S must go to a logic "1" (meaning that all the start-check permissives must be satisfied, and a START must be active, and all permissives to run the turbine must be satisfied).

Or what?

 

[slowmotion]

Or what?

Nay. A sharp smack with a lump hammer, mate.

 

[mickle]

Meh.

 

[slowmotion]

...and stick a Megger on the dodgy gas valve solenoid....

 

[GrumpyGregry]

Filling a system is a one man job so I can't imagine why just bleeding them requires two.

the install/commissioning instructions on mine suggest both filling and bleeding may be easier done with two....

 

[Gixxerman]

Or what?

This is engineering porn!
I take it that you haven't always been a plumber / heating engineer. Ex RAF ground crew per-chance?

In summary yes (assuming that you are applying the standard failsafe logic of logic '1' meaning healthy).
You should not be able to start the unit unless all pre-start conditions are met L.O. pressure is just one of them. Our engines has as much as 50 or so pre-start conditions. The I/O count on a typical turbine (with driven unit) is about 500 devices. The whole of the code has to run on a 10ms scan rate, including servicing the I/O.
It looks like you are talking about a quite old control system (relay logic?), or possibly ladder logic on a PLC?
I use modern PLC's that are programmed with high level languages (SCL, STL) or graphical programming languages (FBD, CFC, SFC) and also real-time embedded system programming in c / c++ / assembly. I also write communication drivers, so if you need any help there, you only need to ask.

 

[Dan B]

Gas turbine control systems eh?. Would you say that L4S is a "momentary" logic signal which will go to a logic "1" when a unit START is initiated and all the start permissives, including sufficient L.O. pressure, have been satisfied. L4T is the logic signal which will be a logic "1" when any trip (emergency shutdown) condition is detected by the sequencing or application code, such as low-low L.O. pressure, or high-high vibration, or exhaust overtemperature. L94T is the logic signal which will be a logic "1" when a normal, automatic non-emergency shutdown is active and the unit reaches the point at which the fuel is to be shut off. In order for L4 to be energized (go to a logic "1"), L4T must NOT be a logic "1" (meaning there must be no active trip conditions detected), L94T must NOT be a logic "1" (meaning that a normal shutdown is not active and fuel does not need to be shut off), and L4S must go to a logic "1" (meaning that all the start-check permissives must be satisfied, and a START must be active, and all permissives to run the turbine must be satisfied).

"Well?"
"Er, what does the Z mean?"
"Which one?"
"Any one"

 

[zacklaws]

[QUOTE 1271816"]
I woke up to our Worcester combi boiler gurgling away merrily this morning. What's wrong with it?
[/quote]

That was one of the symptoms I had when my condensate pipe had froze over. The boiler probably keeps working untill the pipe is completly full of ice and no where for the condensate to go.

As for fitting a 2 inch pipe instead of a 3/4 inch pipe, it made no difference to me, I ended up with a 2 yard long, 2 inch pipe packed end to end with ice.

I removed the 2 inch pipe, heavily insulated the stump poking out of the wall and it seems OK now, just get up every morning now to remove an icicle up to 18 inches long now from the long overhang of the insulation but the pipe remains unfrozen..

 

[cisamcgu]

[QUOTE 1271816"]
I woke up to our Worcester combi boiler gurgling away merrily this morning. What's wrong with it?
[/quote]

We had a similar problem. The boiler man found that the small container that holds the condenser water was full of sand and wasn't allowing the water to drip out. He at first thought that the pipe was frozen.

Hope this helps, or at least points in the right direction.

 

[Gixxerman]

"Well?"
"Er, what does the Z mean?"
"Which one?"
"Any one"

Nice HHGTTG quote BTW.

Good question though. The Z stands for position in the standard ISA device tagging scheme.
This then has a number of subsequent letters that are qualifiers (e.g. S=Switch, T=transmitter, D=Differential)
For example: ZS123 would be Postion (Z) switch (S) number 123 and ZT456 would be Position (Z) transmitter (T) number 456.

Hope that helps.