DIY Doctor

Main navigation

No heat in radiators with boiler with header tank

Postby Bookertmgs1 » Sat Dec 11, 2021 10:30 pm

I have an old conventional boiler with a header tank.

House is a bungalow.

I have just replaced 3 radiators and valves. I have cut back the old pipe work under the floor and connected new copper to the new valves.

There is no drain point in the system. I used a washer hose connected to old rad valve to drain.

Before draining the system I added some sentinel system cleaner 24 hours previously and ran for 24 hours.
Heating was working this morning.

Connected everything back up today and filled system up. Water has filled radiators and I have bled each radiator.

Boiler is running and pump seems to be working - but doesn’t appear that any hot water is moving through pipes. Pipes immediately above boiler are hot - but nothing further down pipes.

Pump is less than 12 months old and is a granfos one

Anyone offer any advice with what I need to do next?
Rank: Labourer
Progress to next rank:
Posts: 2
Joined: Sat Dec 11, 2021 9:27 pm


Simply Build It

Postby ericmark » Sun Dec 12, 2021 6:10 am

Double bleed radiators, do it with only supply tap/TRV/lock shield open and return closed then with only return open and supply closed, so supply and return both bled. Then try again.
Rank: Project Manager
Posts: 2833
Joined: Fri Oct 02, 2009 8:49 pm
Location: Llanfair Caereinion, Mid Wales.

Postby Bookertmgs1 » Wed Dec 15, 2021 1:02 pm

Many thanks for the reply - problem was an airlock above the pump which stopped the water moving

I didn’t see a tail with a bleed valve on it. Opening and reliving the air solved the issue.

Thanks again for taking the trouble to reply
Rank: Labourer
Progress to next rank:
Posts: 2
Joined: Sat Dec 11, 2021 9:27 pm

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics