Glo-worm Ultracom 38cxi - Keeps on firing up....

[shaunos]

I'm wondering if someone can help with this problem as it's really annoying.

Boiler works fine for hot water no problem.

On the heating side, it's got the wireless room-stat, which works well, with the timer elements.

i.e. at 1630 the boiler turns on and promptly does it's best to get the room to 19c for instance.

Once it's got there, it stops going at full whack....

BUT...

Every 60 seconds or so, it gets to the point where it realises it's warm enough, and doesn't need gas etc, and turns off (well it goes quiet), I presume it's the pump/fan stopping.

5 seconds later, it changes it's mind, powers up, 4 flames of gas usage, heats up for 10seconds, then does the process again. This continues until the timer tells it to turn off.

It's obviously not right, but am not sure what is causing it.

Any help/advice please.

It's NOT the wireless room stat, have tried a different one, and the problem remains.

 

[shaunos]

Ok,

I may have solved my own problem, but will post to see if it's a likely resolution.

I was looking through the advanced settings in the hidden menu and found something called "Modulation"

This was set to on, just changed to off, and it appears to have done the trick?

What's this do then?? What is it's purpose?

 

[elecguy]

modulating mode will simply keep the room at temperature more steadily than the simple on off mode of normal room stats.

i would suspect you may have a circulation issue and while this is shortly soved by turning modulation off it may well re occur.

check d.40 and d.41 in the diagnostic list d.40 being the flow d.41 being the return these shold be no more than 20 degrees apart if they are at 20 or more apart then i would suspect trapped air, debris in the pipework or weak pump.

 

[Agile]

Modulating would be the normal mode.

Stopping it will seriously affect the efficiency and could lead to smaller flows of HW going hot/cold.

Tony

 

[elecguy]

agile is right, it will also affect your efficiency, however not detrimental to the boilers life span

 

[shaunos]

Modulating would be the normal mode.

Stopping it will seriously affect the efficiency and could lead to smaller flows of HW going hot/cold.

Tony

Tony,

Thanks for the reply, but the manual for the Climastat says modulating is off by default.

Page 20

http://www.glow-worm.co.uk/products/pdf/accessories/ClimaproRF_installation_servicing.pdf

 

[shaunos]

modulating mode will simply keep the room at temperature more steadily than the simple on off mode of normal room stats.

i would suspect you may have a circulation issue and while this is shortly soved by turning modulation off it may well re occur.

check d.40 and d.41 in the diagnostic list d.40 being the flow d.41 being the return these shold be no more than 20 degrees apart if they are at 20 or more apart then i would suspect trapped air, debris in the pipework or weak pump.

Thanks, will check later.

 

[Agile]

XXX From page 18 XXX

• The modulating operating mode must be selected before
this control will modulate the temperatures of the radiators
to achieve the room temperature set point.

That is what I read!

I am asuming this is a combi boiler ?

Page 20 tells you how to set/unset the modulation and when you should disable it. ( With a hot water cylinder! )

As stated we think you have a blockage/flow restriction.

Tony

 

[shaunos]

It's quite possible.....but, how do I find it?

All the rads are heating up.....so there doesn't appear to be a blockage, but is there a way to test?

Will post results from d40 and d41 a little later.

 

[mickyg]

how many rads have you got?

The modulating can be set on or off
when off it will work as a normal room stat. when on it will ramp down as it reaches the set temperature. Both should work adequately, the later should be better.

 

[Agile]

I dont think so Mick.

If the stat is just an on/off then the boiler will STILL modulate as the rads heat up and thus run for longer at lower power output.

If the boiler modulation is REALLY set to be oFF then the boiler can only run on the full set power and turn on/off to give time devision modulation.

Under the control of this stat the boiler power is reduced as the room temp reaches close to the set temperature. ( There is also a new Worcester room stat that does that ! )

HOWEVER, it could be that the modulation "off" setting only relates to modulation initiated by the remote control stat.

But seeing the setting for turning off the modulation that seems less likely.

Does anyone know the reality of this?

Tony

 

[mickyg]

I did not say the boiler would not modulate! just that it would turn off the roomstats ability to modulate the boiler.

 

[mickyg]

btw I have fitted half a dozen of these with no problems. I'm guessing the op has got half a dozen rads and its cycling. The boiler needs range rating if so and will prob help the problem.

 

[Agile]

I am pleased to hear that you also range rate them as thats also what I advocate.

Others here dont think thats necessary because they say the boiler modulates and so its not required !

Tony

 

[shaunos]

Ok,

To answer some questions.....

d40 was 52

d41 was 50

or the other way around, but pretty close.

Number of radiators....errm, more than 6, it's actually 18.

With regards to the modulation, I think there are two elements to it;

a) Boiler modulation

b) Modulation control on the Climastat RF Pro...

I haven't touched the boiler settings.....only the ones on the RF Stat.

What do you think?

What's this range rate thing?

2 days on, and boiler still behaving....(and yes the boiler itself is modulation the burner).