No Heat

[blueboyjim]

Please Help. Having read previous posts re cold radiators i took advice drained system, cleaned radiators, added a sludge remover and refilled.
I am getting no hot pipes to any radiator. The system is a back boiler microbore pipework with bi-flow valves. any suggestions greatly appreciated

 

[ollski]

pump?, motorized valve?, we need more information on the type of system and what is working

 

[blueboyjim]

Hope this is of help to the experts. The system is a basic gravity circulation system with hot water tank. It is a microbore system with flow/return valves fitted to all 7 radiators. As for as i know there are no zone valves or anything complicated like that. The pump is operating and was changed approx 8months ago. The pipework from the boiler is hot on both gravity and pump systems but the ruturn pipework at the pump is cool. The pipework too/from radiators is cool. Please contact is any more info required. Thanks

 

[AnonymousImport]

I know the type of system you have. Unfortunatly if the pump is running and working ok then you have a blockage . When you drained the system all the sediment and sludge collected in the low points in the pipe work. It has now gathered some where between the pump and the manifolds where the microbore connections are.

Check to see if there is heat after the pump. The pipe work should be hot. If it is then I would locate the manifolds, under the floor, cut them out and clear the sludge that is blocking them. Worst case senario would be each individual micro pipe blocked (unlikley).

If the pipe work after the pump is luke warm then there could be a problem with the pump.

Gasman

 

[blueboyjim]

Thanks Gasman for your reply. Between work commitmentas and christmas i have not had a chance to do anyfurther work. I can never seem to get both manifolds hot at the same time ie supply manifold hot return cool or when radiators are vented return manifold gets hot and supply cool. Any further suggestions greatly appreciated

 

[oilman]

Not much can be suggested, as Gasman says, you have a blockage. You will have to cut pipes to find out where it is.

 

[DP]

Are the flow and return pipes at the HW cylinder getting hot?

Can you post pipe sizes to HW cylinder?

Not all microbore installlation were fitted with manifolds.

I suspect your system is airlocked.

 

[ChrisR]

Vent the pump by undoing screw and check any bleed points in airing cupboard.

 

[blueboyjim]

Thanks DP and ChrisR. DP the gravity hotwater pipes to the Hotwater Tank are 28mm reducing to 22mm for approx 3ft to connect onto tank and both pipes are very hot. The central heating circuit pipes are 22mm to manifolds then 8mm take-offs. ChrisR i have vented the pump numerous times and am getting water at a trickle every time.