Circulation Issues, pls help

[81ll]

People, please can I have your help on a circulation issue (these are the issues I struggle with more than anything)?

Here goes:
- system is open vented y plan
- new pump has been installed
- new three port valve with actuator has been installed
- system has been powerflushed properly
- but still poor circulation / boiler locking out with F25 error
- I can feel heat on the flow on the DHW Cyc but nothing on the return
- also feel heating just after zone valve but nothing another 0.3m down the pipe
- checked the pipework in the airing cupboard with a magnet & found no signs of magnetic force. So I'm thinking cold feed is ok
- system doesn't circulate on HTG or DHW, boiler shoots from 20-80 degrees in seconds
- when it doesn't lock out, it gets to temp then burn goes off. Then comes on again.........
Any suggestions, your assistance would be greatly appreciated

 

[ShaunCorbs]

Nrv on the pipework sometimes

 

[81ll]

Nrv on the pipework sometimes

Any ideas where I should be looking for the non return?
Wouldn't that just stop me back filling?

 

[ShaunCorbs]

Would say on the primary return/ by the airing cupboard

You sure you have no air locks in the return?

 

[81ll]

Would say on the primary return/ by the airing cupboard

You sure you have no air locks in the return?

Could be an air lock I'm not sure. I did shut off a Rad then replaced the bleed valve with a pipe. Then opened both valves at diff times, wouldn't that have cleared the air lock.

Plus customer has had this issue for a while, I'm the 3rd person who has worked on the system

 

[81ll]

Would say on the primary return/ by the airing cupboard

You sure you have no air locks in the return?

How could I be sure

 

[ShaunCorbs]

Is there a drain point at the boiler ?

 

[81ll]

Is there a drain point at the boiler ?

On the return I was gonna try draining from that, could that work

 

[ShaunCorbs]

Pump on the flow ?
Maggy on return?

 

[81ll]

Pump.is defo on flow, no filter on system

 

[Sid Viscous]

Sounds like an horrendous air lock. If there's a drain point low down on the system you could try emptying it then back-filling from the ground up. You'll need someone in the lord keeping an eye on the level in the f&e though...

 

[81ll]

I'll give it a go

 

[81ll]

Sounds like an horrendous air lock. If there's a drain point low down on the system you could try emptying it then back-filling from the ground up. You'll need someone in the lord keeping an eye on the level in the f&e though...

I have already isolated a Rad, then connected a hose to the outside. Then opened 1 end at a time for a few mins.

Wouldn' that have cleared an air lock???

 

[Vee]

What boiler is it? I’ve had circular heat exchangers badly blocked to the extend that they needed replacing.

 

[king of pipes]

you could have a restriction in the heat exchanger happened to me recently on a valliant . cheers kop

 

[dan_the_plumber]

Have you thought about cleaning the Primary filter?
Of course it’s worth running cleaner for s week then flushing too

 

[TonyC]

Have you checked that zone valve is opening fully?

 

[the_d_o_t]

I had a issue similar a few week back,
Turned out that the ERP pump was faulty
The digital screen display looked like the pump was running and in fact would intermittently but ultimately would stop and the display would stay the same.
Pcb in pump frazzled and replaced with a standard pump

Sorted issue

 

[Neil Callaway]

Did the boiler run correctly when powerflush unit was connected, or did the temps still rise the same?

 

[Vee]

Flow and returns reversed?

 

[Last Plumber]

Which boiler is it ?