Anyone understand Logic combi boilers?

[cliveb]

We have a Logic 30 combi boiler.
The heating is currently switched off.
The preheat function is switched off.
But occasionally we hear it firing up for brief periods (less than a minute) even though we're not using any hot water. (It's in the loft, and by the time I get the hatch open to look for any message on the display it has shut down again)

Anyone have an idea why it would fire up briefly?

 

[RichA]

Dad's got a Worcester Bosch combi. There's a setting where I think it keeps a minimal volume of water preheated for "instant" hot water. Could it be the preheat setting is on?

 

[cliveb]

Dad's got a Worcester Bosch combi. There's a setting where I think it keeps a minimal volume of water preheated for "instant" hot water. Could it be the preheat setting is on?

As I said in the OP, preheat is switched off.

 

[RichA]

As I said in the OP, preheat is switched off.

Sorry didn't see that. The WB controller is a nightmare. Even the central heating engineer who's been out to service it hates it and thinks it has a mind if it's own outside the programming.
Don't most modern systems pump the water around for a minute a couple of times a day, even when dormant?

 

[jim8flog]

I have a Vaillant and it does this as a self test of the system (mine is next to the kitchen sink so I can see it says so on the display).

 

[kp17]

Yeah we have a logic combi I think it fires up to self test once every 24 hours

 

[cliveb]

I have a Vaillant and it does this as a self test of the system (mine is next to the kitchen sink so I can see it says so on the display).

Yeah we have a logic combi I think it fires up to self test once every 24 hours

Thanks chaps. I guess that must be what my boiler is doing.
Where's bunkermagnet when you need him? He's bound to know.

 

[rudebhoy]

We have a Logic 30 combi boiler.
The heating is currently switched off.
The preheat function is switched off.
But occasionally we hear it firing up for brief periods (less than a minute) even though we're not using any hot water. (It's in the loft, and by the time I get the hatch open to look for any message on the display it has shut down again)

Anyone have an idea why it would fire up briefly?

I've never heard of anyone having their boiler in the loft. Why would you want to do that? Only advantage I can see is you free up extra cupboard space in the kitchen, but sounds like a load of hassle, both to fit it there and also to check on it. I'd be worried about not knowing about a leak until it's too late.

 

[Tashyboy]

Ours was put in the loft when we did the kitchen extension. Brand new Kitchen with a pigs ear of a boiler, not combi. It made sense. Shifted the boiler into the loft. And then got rid of the airing cupboard by knocking it into the smaller bedroom which helped make it a lovely size by using that door.
Re leaks. We had one the day before we went on holiday. The plumber shut the boiler off til we got back. The plumber explained that the boiler would only leak so much then it would shut down due to loss of pressure. So not flooding the house out.

 

[Fade and Die]

I've never heard of anyone having their boiler in the loft. Why would you want to do that? Only advantage I can see is you free up extra cupboard space in the kitchen, but sounds like a load of hassle, both to fit it there and also to check on it. I'd be worried about not knowing about a leak until it's too late.

It’s not uncommon but it is a PITA every time you need to work on them.

 

[jim8flog]

Boiler in the loft Not something I would do but you can see it around here base upon the flue location which can be seen from the outside of the buildings. (I did have major advantage about location because I was fitting a new kitchen at the same time)

Hard to check basic functions such a water pressure
I change the temperature of both water and heating setting to suit use on a fairly regular basis
Combi boiler with water preheat function - I only use mine as needed.
No worries about leaks ruining ceilings.
No worries about the boiler firing up due to anti frost setting of the boiler, mine would kick in at 8 degrees C (my neighbour put theirs in the garage and it fires up almost constantly in colder periods).

 

[cliveb]

It’s not uncommon but it is a PITA every time you need to work on them.

Our loft is enormous, boarded, loads of room to move about. Also has shelving where most things are stored. No problems doing anything up there. I sometimes think it's the best room in the house!

 

[Fade and Die]

Our loft is enormous, boarded, loads of room to move about. Also has shelving where most things are stored. No problems doing anything up there. I sometimes think it's the best room in the house!

Maybe your loft is the exception because most of the times you have to climb up there from the top or your steps, there is no light, there might be a board in front of the boiler but often not, its freezing and the boiler is tucked into the far corner. Like I say. PITA