New Potterton Heatmax 33kW Issue

[Bluecarisma]

I fitted a 33kW Potterton Heatmax combi boiler a couple of weeks ago and just been back to fit a radiator at the premises.

Whilst i was there the customer said is it correct for the boiler fan to come on when a cold water tap is used?!

I thought this was strange and investigated, i turned on the cold kitchen tap and let it run for 15 seconds or so and low and behold the boilers 'starting' procedure began, (pump and fan within the boiler but no ignition).

Now, from what i understand the Potterton has a frost protection function and a 24hr run through cycle function. Ive never fitted a Potterton before but thought id give it a go due to a good deal through Plumbase.

What im needing to know is this normal working procedure for a Potterton or do i have to call out heat-team to have a gander?! Since it is only 2 weeks old!!!

Hope someone can help!!

 

[Poxi]

Do you have a hot water dead leg..i.e in your airing cupboard, If so cap it off nearer to the main run or undo the cap if compression and see if any air comes out.

 

[Billy Bob Bob]

i would tend to agree there's a hot dead leg somewhere this would effect any brand of combi

 

[Bluecarisma]

The boiler is where the old airing cupboard used to be.
There was two hot water expansion pipes going to the cold storage tank in the roof space, one copper and one galvanised.
When converting the system to the pressurised combi, i obviously took out the storage tank, associated copper pipe work and cut the galvanised pipe back to the nearest fitting and put a 3/4 plug in it.

This would be the only dead leg for the hot water which would most definately have air in it. The property has a loft conversion and the galvanised pipe is not accessible up there but i had planned to take it out when I renew the bathroom in the next couple of months. I traced the galvanised pipes back from a capped off vanity unit in a bedroom back to underneath the tiled bathroom floor.