Central heating not circulating after New Navien Combi fitted to Santon Premier system.

[ShaunCorbs]

Yes so that in theory is good

Did they remove the external pumps ?

 

[JohnHuson]

No changes were made to the radiator system apart from adapting the 40KW combi to the system and the non vented
cylinder remained as it was. My concern is that is a combi 40KW combi capable to feed a system with 22 to 54mm
feed around two zones? This is a Pub so the 23 rads need a supply which can be quick and efficient. We have now got
heat in around nine of the 23 rads. That has taken two days of the boiler running.
The system has been purged of air, rads bled, drain feeds on each point to at least 10 gallons drained.
I would add that the system worked well prior to the installation of the new combi boiler.
The installer has suggested the TRV's are stuck. They are not, and the flow of water within the circuits are free of problems.

 

[ShaunCorbs]

And the old pump was it removed or left in ?

 

[JohnHuson]

And the old pump was it removed or left in ?

The secondary pump was changed but was working fine on all three speeds so original pump was refitted.

 

[ShaunCorbs]

Any chance of a few pictures of how they have pipes it ?

 

[JohnHuson]

The secondary pump was changed but was working fine on all three speeds so original pump was refitted.

The original pump in the old boiler was scrapped when the boiler was removed. The Combi internal pump
I hope is doing its job. The secondary pump on the cylinder cold supply is working as it should.
This is driving me nuts!
Either there is a circulation problem caused by lack of pump pressure from the ne combi or a restriction that
has suddenly appeared on the change over?

 

[ShaunCorbs]

There you go the internal pump of the new boiler is not man enough for the system it needs the old pump back on / one sized correctly

 

[JohnHuson]

There you go the internal pump of the new boiler is not man enough for the system it needs the old pump back on / one sized correctly

I guess you are right. If it needs an additional push pump where in the system should it be located to move things around?

 

[ShaunCorbs]

Should be after the llh

I hope there’s additional expansion tank / tanks ?

 

[SJB060685]

Sounds like you need to separate the system. Also is the old boiler a non condenser @ShaunCorbs and the rads possibly ∆T 60?