Worcester Greenstar 30Si compact - heating turns off when there is demand for hot water?

[volks]

Hello, had this boiler fitted at the beginning of the year. Only just noticed this quirk today after the fold weather hit and a bit of investigation.

If central heating is on, thermostat is on, the boiler fires for heating and displays the radiator symbol. If I turn on any hot tap however, the boiler fires to heat the tap water and turns off radiator heating.

Once the hot tap is turned off, it takes about a minute for the central heating to fire up and continue.

I've got the radiator flow temperature set to 51 degrees, hot water is at 52. The boiler is on eco mode, so it doesn't waste gas preheating hot water 24/7. I tried turning eco mode off, but as soon as I ran a hot tap, the central heating turned off while the tap was running.

In the grand scheme of things it's a minor issue, but is it normal? It's also kind of frustrating as if I turn the heating on when I come in, then go for a shower/bath, the heating won't have warmed the house up until I've finished showering, which is frustrating. Getting out a warm shower to a cold house.

Is there anything I can do to resolve this? The manual doesn't mention this functionality/issue at all.

All I can think is, my house has a lower than average water pressure/flow rate. Could it be swapping as there isn't enough water pressure to handle both scenarios? Though now I think about it, that doesn't make sense as the heating is a sealed system.

Please help if you know anything about this, it's driving me slightly mad!

 

[Gasguru]

It's a combi boiler and that's how they all work. If your home is loosing so much heat in the time it takes for a shower you've got some serious heat loss issues.

 

[volks]

It's a combi boiler and that's how they all work. If your home is loosing so much heat in the time it takes for a shower you've got some serious heat loss issues.

Not losing heat, just more that I've come into a cold house and want to heat it up while I shower, but it can't do that until the hot water demand is over.

I swear I've not seen my parents combi boiler do this, but perhaps I've never noticed until now.

 

[Madrab]

+1 .... combi's work on hot water priority therefore when the HW tap is opened it diverts the water from the CH output into the Plate HEX where it heats the cold water and then switches back once the cold tap is closed, they don't do both. Some switch back to into CH mode and fire back up quicker than others.

 

[volks]

Well damn, looks like I am just an idiot. Well thanks for the swift answers and saving me from asking a gas engineer about it. That would have been embarrassing!

 

[Gasguru]

Are you sure your parents have a combi and not a conventional/heat only or system boiler combined with a cylinder?

I vaguely remember one combi model many years ago that had the ability to share the heat output simultaneously between heating and hot water depending on hot water load...but I may be mistaken.