New boiler not working

matty_hunt

Hi.
Ive just had a new condensing boiler installed but the plumber cant get it working. The system is at correct pressure and when switched on the boiler light flashes to signal correct operation. (though there is a loud 'electrical transformer' kind of sound. Much louder than I expected. As loud as the fridge!)
When CH is switched on the pump whirls with initially bubbly sounds then quite. The lights flash to indicate CH working but there is no ignition I can hear or see though the little spy window. After a minute it all stops and the warning light flashes to signal, 'no water or absence of flow'.
When the hop tap is opened water rushes out but the boiler does nothing except that a little red sensor light comes on the cold water inlet valve. So no hot water but there are no warning lights to say the lack of burner ignition or flame detection error.
Any ideas? The plumber thinks the pump is faulty as it has an elecrical block plugged into it. Its a Biasi that has stood in the box for a good three years.
I have also noticed that the old cylinders flow and return have been reversed now the new boiler in directly connected. Will this cause an issue? All the rads have TRVs with a little arrow on them pointing into the rad.

Any advise welcomed. Thankyou.

Consumerist

Sounds as though the system has not been properly bled of air. Try the pump's air bleed.

matty_hunt

Thanks. Thats what I initially thought but I have bled the heat exchanger, the pump, the magnaclean and the rads and its all good.

Consumerist

Well, I don't pretend to be an expert but have installed a boiler in the past.

If the gas isn't firing-up then it's either a lack of water flow (through the heat exchanger) or a lack of air flow through the combustion chamber. Best I can offer at a distance, I'm afraid.

Consumerist

P.S.

I'm assuming that the gas is turned on (yes, you'd be surprised at the silly things we forget) and that the ignition circuit is working ok.

matty_hunt

Yep. Ive double checked. Oddly, even with the gas switched off the no gas warning lamp doesnt come on.

Consumerist

There will still be pressure in the gas pipe until the gas switch turns on for a fire-up.

Consumerist

If you've got the installation manual, I would suggest you take the boiler through the entire commissioning procedure.

Edit
Silly thought but have you made sure that any air in the gas pipe has bled out so you are actually getting gas into the combustion chamber?

BaldPlumber

Consumerist wrote: »

Silly thought but have you made sure that any air in the gas pipe has bled out so you are actually getting gas into the combustion chamber?

Why are you attempting to give advice on safety critical matters?

OP is your 'plumber' a registered gas fitter?

gas4you

Has he checked that the electric polarity is the correct way round?

Other than that, why hasn't he put a call in to the manmufacturers under warranty?

BaldPlumber

gas4you wrote: »

Has he checked that the electric polarity is the correct way round?

Other than that, why hasn't he put a call in to the manmufacturers under warranty?

Because it's a three year old Biasi?

OP, Does the installer have a multimeter and is he GS registered?