My friend have a central heating system with "potterton suprima l"
(no modulation control) she leave the system on 24 hours a day and only
the bathroom radiator is on. The boiler fires every 5 min for 30 sec.
I have a Worcester 24CDi (With modulation control) when I do the same
thing (only bath radiator) my boiler fire every 3 min for 15 sec.
I was sure that my boiler will fire the same as her but it look as if
it's fire more.
Is the boiler fire times are programmed in to it? Is my boiler fire
every 3 min and worm the Ch water to the set tamp and her programmed to
fire every 5 min? Or is the boiler fire only when the water in the
system going cold below a specific temperature? After watching both
boiler it look like they are programmed to fire in specific times. I.e.
her every 5 min and mine every 3 min.
It looks as if my boiler uses more gas than her.

In article .com,
"Golan" writes:
My friend have a central heating system with "potterton suprima l"
(no modulation control) she leave the system on 24 hours a day and only
the bathroom radiator is on. The boiler fires every 5 min for 30 sec.
I have a Worcester 24CDi (With modulation control) when I do the same
thing (only bath radiator) my boiler fire every 3 min for 15 sec.
I was sure that my boiler will fire the same as her but it look as if
it's fire more.
Is the boiler fire times are programmed in to it?

No. Some boilers force a minimum gap between firings, largely to
overcome thermostat 'bounce' which can go on for a minute or more
when a grotty thermostat is handling a slow temperature change.

Is my boiler fire
every 3 min and worm the Ch water to the set tamp and her programmed to
fire every 5 min? Or is the boiler fire only when the water in the
system going cold below a specific temperature? After watching both
boiler it look like they are programmed to fire in specific times. I.e.
her every 5 min and mine every 3 min.
It looks as if my boiler uses more gas than her.

It's just a function of the amount of water (and pipework, radiator,
boiler, etc) to be heated, by how much it needs heating, the power
the boiler puts into it, and how long it takes to cool enough to
trigger reheating. It would be unlikely two different systems would
have the same timings. You can't infer anything about the relative
gas consumption from the data you posted, but your Worcester is
probably more efficent.

--
Andrew Gabriel