Worcester Bosch R28HE confusing behaviour

[stevedo]

I have a Worcester Bosch R28HE installed in the garage

There is a separate Honeywell T4360a frost stat, I also understand that the boiler has its own frost stat.

I am using a Digistat RF3 and SCR receiver, this appears to be operating the boiler as it should.

The pressure shown on the boiler is normal, i.e. in the green zone when up to temperature.

It is/has been very cold here lately (min -8 over night and no more than about 0 - 2 during the day.

What's confusing, and has not been normal behaviour, is that when there is no demand for CH according to the RF3 (no green light on the SCR)the boiler continues to "run". What I mean by run is that the boiler sounds like it's running but the indicator lamp for the burner is off and I can see from the gas meter that no gas is being used. Why is this and is it likely to be some kind of fault?

For more information, I've been turning the boiler off during the day and overnight to stop the boiler heating 24/7 I assume as a result of the frost stat kicking in. Could the confusing behaviour be due to the in-built frost stat or a result of me turning the boiler off and on using the master switch?

As a follow-on question, given that all pipes in the garage are well insulated and the boiler has its own frost stat, do I really need the Honeywell frost stat?

Apologies for the long post but I've tried to supply all relevant info

Thanks
Steve

 

[superdupergasman]

The boiler will only have frost protection providing it has a permanent live supply to the boiler....

otherwise the honeywell one is doing its job as it should...however make sure it is turned down to 3oC if it is the sort that is adjustable....

the system should have a pipestat aswell to help stop the boiler firing when its just cold air temp and not the pipes freezing....

So for now...I would NOT be turning off your boiler at the wall as it is protecting itself and then perhaps getting a pipestat fitted in series with the current frost stat to back up the boilers frost protection!

 

[stevedo]

The boiler will only have frost protection providing it has a permanent live supply to the boiler....

otherwise the honeywell one is doing its job as it should...however make sure it is turned down to 3oC if it is the sort that is adjustable....

the system should have a pipestat aswell to help stop the boiler firing when its just cold air temp and not the pipes freezing....

So for now...I would NOT be turning off your boiler at the wall as it is protecting itself and then perhaps getting a pipestat fitted in series with the current frost stat to back up the boilers frost protection!

Hi, thanks for the reply. I understand what you are saying and I've just turned the frost stat down a bit, was on about 5 degrees C.

However, I still don't understand why the boiler still seems to keep running without using gas (it never stops). For example. The roomstat is set at 20 degrees C, the room is at 20 degrees C and therefore no demand on the boiler for heating but the boiler continues to run although the lamp burner light is not on and no gas is being used.

Why does the boiler continue to do this and is it a problem.

Thanks
Steve