Worcester Greenstar 24ri - Possible airlock?

[JE-P&H]

Replaced an old Ideal Concorde WRS225a with a 24ri today, on fire up it lights for couple of seconds and overheats causing banging pipes etc.

Couldn't find a manual for the Ideal so assumed flow was on the left and return on right as left came out from top of heat ex and right from the bottom. (Check with Ideal who confirmed I was correct but still considering it's a possibility)

Have a drain off on the return so tried mains water into the system with no luck.

Boiler is in the garage with about a 8m run to the airing cupboard where the pump is, flow pipe barely gets hot past top of the boiler. Any suggestions would be great I'm struggling!

 

[PhoenixServices]

Have you bled the heat exchanger?

 

[JE-P&H]

Ye bled from the vent on the top, no air just hot water!

 

[Destroyer2813]

Checked the simple things right pumps running valves are open filter vales or anything ?

 

[JE-P&H]

Ye pump runs ( Can hear it and changes through speed settings) zones valves both opening and are new, pump is still original was working fine before I assume as they had HW do newer boilers need a strong pump could be weak but unlikely?

 

[ShaunCorbs]

how fast does it temp up?

 

[JE-P&H]

About 10seconds, fires up full then goes low, then out as it overheats. Flow pipe goes red hot above boiler and return gets hot but it doesn't loop, the pipes just get hot off the boiler if that makes sense!

 

[ShaunCorbs]

would say air lock

shove your hose on the drain off and drain it off for a good 10 mins on the return then do the same with the flow

 

[JE-P&H]

Ye same I was thinking tomorrow drain it down put lever valve on flow and one on return. Then mains water through the drain off isolating one side at a time to try and push it through but if that doesn't work I'm stuck haha!

 

[ShaunCorbs]

Ye same I was thinking tomorrow drain it down put lever valve on flow and one on return. Then mains water through the drain off isolating one side at a time to try and push it through but if that doesn't work I'm stuck haha!

dont you have a mag filter fitted?

 

[JE-P&H]

I Quote them as optional customer opted out, not my choice but what can you do!

 

[ShaunCorbs]

I Quote them as optional customer opted out, not my choice but what can you do!

just thinking saves you draining down if you did

would put some lockshield gate valves instead of lever valves

 

[JE-P&H]

Ye it's typical majority of installs have a filter but not this one! Didn't think of lockshield gate valves good alternative thanks!

 

[JE-P&H]

Still no luck, drained everything including the boiler installed 2 AAV above the boiler shut off a valve each side and tried to pull an air lock through any other suggestions?

 

[ShaunCorbs]

Are you getting just water out ? Or nothing

If your getting water could be pump

 

[JE-P&H]

Just water, I have now changed the pump still the same have also swapped Flow and Return round above the boiler temporarily to see if that does anything and no luck! Baffling me system was quite old fully pumped system before but had no motorised valves etc just a Damfoss mixing valve controlling the hot water temperature anything I could have missed?

 

[JE-P&H]

Photo of pipework before I took cylinder out if that helps!

I have labelled them left to right as they come out of the floor Boiler flow, Boiler Return, CH Return and CH Flow anyone disagree?

 

[Gasmk1]

is pump on flow or return might make a difference

 

[JE-P&H]

I would say Flow? From the picture above it pumps to the cylinder and is on the flow pipe into cylinder?

 

[Chuck]

Deleted after I re-read the OP.

 

[JE-P&H]

Here's a picture just after I changed the pump with my pipework anyone see anything I'm out of ideas now haha!

 

[Gasmk1]

I think you should have put an air vent on the top of the heating coil, could be locking up there

 

[JE-P&H]

I think you should have put an air vent on the top of the heating coil, could be locking up there

Where do you mean top of the coil? I don't think it's an air lock anymore I've put mains water through the system right up to the tank and still boiler flow doesn't even get hot heat exchanger just overheats.

 

[Old Account]

As @ShaunCorbs mentiond earlier it might be your pump itself. @Gasmk1 said you should put an AAV on top of the coil which means where the inlet to the coil is - basically close to the coil entrance. If there is no airlock anymore try getting another pump that's what I would to see if there is any difference.

 

[Chuck]

This is turning into quite a mystery.

Neither of the following are likely, just trying to think outside the box:

Can you be sure that the coil in the cylinder is not blocked? Perhaps a manufacturing problem. Perhaps some bungs to stop debris getting in that needed to be removed...

I can't see from the photos, does the cylinder have a secondary return? Is it possible you connected to this and capped the primary return instead of vice versa.