Advice needed.

[gigz]

Check the pump valves are fully open as well.

 

[dilalio]

That area on a vented system is notorious for blockages... Neutral point and potential pumping over cycles crap around F&E tank and back into circuit... Cut out that section and replace get rid of ballofix and gate valve and replace with levers. Consider sealing system up.

 

[Andynorthampton]

So all valves are fully open the H piece has been cut out expecting it to be blocked. So is my only option to pull up floorboards and cut out the blockage?

 

[dilalio]

How far do you go with doing that? Anybody's guess!
You sure pump is circulating properly?
Else it's the power flush route!

 

[Andynorthampton]

Pump is brand new. Power flush has not shifted it.

 

[dilalio]

Ok. Let's rewind...
What did the ppl who did power flush say when they'd finished? "All sorted sir"? Or "f**ked if we know"?

 

[Andynorthampton]

From there point of view the system was clean. No contaminents but boiler still would not fire and displayed no flow. Only by physically removing pipes and turning water supply on have I discovered the lack of water at the boiler.

 

[dilalio]

So, primary circuit is blocked. Motorised valve(s) are open. System fills up and rads bleed air?
You can definitely confirm that there is no water getting to the boiler from the return pipe? Would you risk uncoupling it with cloths to mop up and be able to pop it back into coupling if water present?

 

[Andynorthampton]

Rads fill and bleed and you can hear the water circulating when the pump first starts after filling. The boiler fills via what should be the outlet from the boiler and have disconnected the fill/ return to the boiler and i get nothing.

 

[dilalio]

When they did pflush where did they connect machine? Sounds like block could be at flow and/or return to boiler or within boiler I.e heat exchanger!

 

[dilalio]

So, blockage in return somewhere between boiler and airing cupboard! Can you try a straightened wire coat hanger up the return from boiler or down from airing cupboard? Can you connect a hose to one end and run water from outside tap to it with hose connected at boiler end to drain!

 

[Andynorthampton]

Power flush was connected in place of the pump. So I have established flow from the boiler is clear and that is also how boiler is filling initially. There is water up to the bypass valve. Just nothing between there and the boiler.

 

[Andynorthampton]

I have a 4 m coil drain cleaner that I have tried from both ends and can maybe get a meter each way before hitting what feels like either a tight bend or a t piece. Have sealed a hose pipe in and added a bar of pressure in each direction with the other end open and got nothing.

 

[dilalio]

Wow! What's in there? A marble!
I would use a roll of hep and a couple of fittings to temporarily bypass that run in the floor, just to confirm that is definitely the fault. Then, if proved it'd be up with the floor or reroute that run in new tube, I'm afraid

 

[gigz]

If youve established where the blockage is it will probably be quicker and cheaper to cut and replace the pipework.