Drained Down Radiators - Now Only 2 Out Of 6 Working

[nashville]

SOS

My Victorian terraced has a back boiler with 6 radiators.

I drained down to fit a couple of new radiator valves, then refilled system.

Now only 2 radiators are hot, the rest are stone cold. I have tried shutting off the 2 hot ones, and also played with the pump speed. Makes no difference.

Any ideas please, 'er indoors is not happy!!

 

[Bahco]

Read post 8 FAQs

 

[nashville]

Thanks. I have looked through the FAQs, but I have already tried the things that apply to my system inc; F&E tank filled, bleeding all rads several times, turning off the hot rads to force through to the cold ones - all to no avail.

The only thing I haven't done on the FAQ list is to bleed the pump. Its an ancient SMC one. There's a small very tight screw on the metal impellor casing, is this to bleed the pump?

Thanks for any advice.

 

[kevplumb]

There's a small very tight screw on the metal impellor casing, is this to bleed the pump?

yep and you wont get it out easiest way i found is to close the outlet valve then slacken the union or loosen the head at the allen screws

 

[nashville]

Thanks Kev.

So what you're saying is that I can get any trapped air out through the union or head/impeller cover?

The pump looks ancient, so I shouldn't even attempt to free the screw?

Many thanks.

 

[kevplumb]

The pump looks ancient, so I shouldn't even attempt to free the screw?

every one ive tryed has broken off having said that if you want to have a go feel free you might drop lucky

worst case 1/2 of the head will shear and your no further forward but you aint done any harm either