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Hi all,

I recently bought Glow-Worm Ultracom 2 30 CXI as well as Climapro2 control room thermostat. The reason for my post is that I am not entirely sure the way it supposed to work when it comes to central heating.

Currently the temperature is set to 19 C between 8am and 10pm every day. So the boiler comes on in the morning gets the house (2 bed mid terrace) to the temperature set point and instead of switching itself off ??? stays on ALL day till 10pm when it’s programmed to 15C for the night.

From what I have noticed the pump is on all the time(between 8am-10pm) and the burner fires up from time to time. My confusion comes from the fact that my last boiler and its basic thermostat simply switched itself off(including the pump) after reaching the set temperature.

Is that the way Climapro2 control is supposed to control the central heating? Get the desired temperature and maintain it being ON all the time?

I do understand that when it’s maintaining the temperature it modulates the burner to keep returning temperature low so it stays in condensing mode most of the time. But the burner isn't on all the time it comes on maybe every 10-15min depending on the outside temperature so it’s not calling for heat all the time it’s just maintaining it but the look of it .
Wouldn't that cause excessive wear and tear especially to the pump if it works continuously for 14 hours a day?

The interesting thing is that it switches itself off when it gets 0.5C higher than the set point. The problem is that since it starts modulating when it gets close to the set point it never overshoots therefore it's always on(the pomp at least).

Any thoughts would be really appreciated. Thanks

I would be inclinded to get the installer back to check out the wiring

Thanks for the reply thescruff.

Well, I have already checked the wiring myself. Power supply cable of the spur box connected to well labelled live, neutral and earth inside boiler.
The radio receiver from the thermostat is connected to eBUS - two wires - the polarity doesn't matter according to the manual.
I really don't know where it could be wrong? Unless you can suggest something?

If you get it set at 19c between 8am and 10pm it will until you tell it to do something, don't know the climapro so if my eye gets better I'll do some research.

Assume you've adjusted all the parameters.

Do you have the outside stat by the way.

Thanks for the reply thescruff.

No, I don't have any weather compensation/outside sensor installed.

Well, I set the temperature and the intervals for heating and enabled modulating in climapro2(it only turns the boiler off when gets higher 0.5C than set point regardless if modulation is on or not).

I also tried to change the temperature in the heating circuit(between 65 and 75C) hoping that if I increase it, it will finally overshoot and switch itself off but it always throttles down when it gets close to set point and doesn't overshoot.

Maybe that's the the way it's supposed to work. I'm just concern about the pump working non stop for 14h a day.

maydayone wrote:I'm just concern about the pump working non stop for 14h a day.

I wouldn't worry about that. These pumps are designed to work continuously 24/7 for years and years.

As for the pump running when the boiler is not alight, it could be that the system has been configured for continuous circulation. This is popular in Germany as it is supposed to be more efficient. So, as Glowworm is a subsidiary of Vaillant - a German company - continuous circulation may have been set as the default mode.

Thanks for the replay D Hailsham.

Well, If constantly working pump isn't something to worry about than I'm happy with everything else.

Burner comes on every now and then since it's just maintaining temperature. As a consequence of that it keeps the return temp is about 40-50C so in theory is in condensing mode for most of the day.

Efficiency wise I'm also inclined to believe that it will use less gas turning on the burner on low fire from time to time than wait for house to cool down and than kick in on full power to heat it up. But I guess it's not as simple and depends on many factors.

Insulation is critical for energy efficiency, although I still think you should be able to turn the temperature down when unoccupied, perhaps a call to glowworm