Cold radiators downstairs

[foxy0-0]

Hi all,
I have moved into my house 8 months ago and I have a wall mounted Puma 100e combi boiler fitted upstairs in bedroom. It looks quite new. I have been working away and just returned to find no rads are coming on downstairs. I have followed some advice in this forum and opened all the radiators and then bled each one. Note, only clean water appeared to come from bleed screws. all rads are fully opened each side. The feed pipes are cold downstairs.
Now for the boiler, the pressure was down but the low pressure warning light was not lit. I topped up to 1.5 bar. The boiler lights and heats water for approx.y 2-3 mins then stops with the dial calling for max.m heat. after approx.y 4mins fires up again then constantly repeats the cycle. The pump appears to be working , I have checked by unscrewing the plastic hex nut and it vibrates when moved side to side.
The radiators that are working upstairs do not appear to be very hot when dial is at max.m position.
Any advice gratefully received. Thanks, Foxy.

 

[Bahco]

Look in the FAQ post above for rad problems and balancing your system.

YOU say all the valves are fully open when in fact 1 turn open should suffice if your pump is ok

 

[foxy0-0]

Thanks for your reply, I think there is a problem with the pump or perhaps the boiler