Glow worm 30cxi modulaiting

[hamselv]

My Glow Worm 30cxi pulses on and off very fast like once every second
the green led blinks, and at the flue you can fell the on/off blows and there
is little smell of gas,

It happens especially when using hot water, but sometimes also when just
heating the radiators.

There is no faults showing (F..) and the hot-water gets warm but not too hot,
and it is annoying and the unit sounds a little like an old ambulance.

In the manual on page 37 The Faultfinding diagram the sympton is described

"Does Boiler modulate before desired set point is reached"
yes -> temperature rise too high of flow rate too low

But I cannot find a description of what I should do fix it.

What is happening and what can I do to fix it.

/Peter

 

[Agile]

I would expect that this is a combustion related fault although if its really pulsing that that frequency I cannot guess exactly what the fault is.

In this case I have to advise that you should call a competent CORGI registered engineer.

Tony

 

[hamselv]

I did some further investigation.

When used for central heating with a low temperature (less than 50
Celsius) the unit works as expected - I normally do have it set to a low
temperature.

When I turn the temperature up the unit starts modulating,
just as it did when it makes hot-water.

Finally I turned the boiler off and waited for half an hour and turned
it on again, and now everything is back to normal. I should have
known that this is the way to handle everything with a computer inside.

I am still wondering what has happened, and why they have this
scenario on their fault-finding diagram, but no further explanation.
This is probably not the first time this has happened.

If the boiler uses some kind of adaptive controller it might have
optimised for low temperatures and have saved some erroneous
parameters which prevent higher yield. I am just guessing.

/Peter

 

[Agile]

And long will you guess!

You are not aware that on higher settings the boiler burns more gas and produces more products of combustion.

If there are defects with the fan, gas mixture or flue, then these may be more apparent at higher power levels.

Tony