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!

 

[Old Account]

Perhaps you mixed some pipes

 

[JE-P&H]

If the coil was a blocked surely CH and bypass would still work so boiler would still fire?

No secondary return on the cylinder just your standard fittings, I didn't cap any pipes tee all the returns in together and used the CH Flow. Open to suggestions if I've mixed something up? I checked the installation instructions for the old damfoss mixer and return comes out the bottom as I expected.

It also now has a new pump on no change!

Got Worcester coming tomorrow to check the boiler to rule that out, took the flow and return off and blew through to ensure no blockage etc. All clear!

 

[ShaunCorbs]

Have you opened port valves manually ?

Do you get any heat up to where the pump is ?

 

[JE-P&H]

Have you opened port valves manually ?

Do you get any heat up to where the pump is ?

Ye opened them manually, no heat and the pump heat doesn't get past the top of the boiler it basically boils itself in about 10-20secs then flow sensor cuts in! Takes a while to cool then same again!

 

[Old Account]

There is only one thing left the boiler itself. It would be quite weird if the boiler is ok.

 

[JE-P&H]

There is only one thing left the boiler itself. It would be quite weird if the boiler is ok.

I know I've ruled everything else out as far as I can see but Worcester technical just say it's a circulation issue so I have asked for an engineer visit as the Heat literally doesn't leave the boiler!

 

[Old Account]

I know I've ruled everything else out as far as I can see but Worcester technical just say it's a circulation issue so I have asked for an engineer visit as the Heat literally doesn't leave the boiler!

I know you've changed the port valves but perhaps faulty ? It would be very weird if two are faulty but just trying to figure the solution

 

[Chuck]

Tell us something about the controls. Is it possible that the circulation is not starting until a few seconds after the boiler fires?

 

[JE-P&H]

Tell us something about the controls. Is it possible that the circulation is not starting until a few seconds after the boiler fires?

Pump is wired to the boiler on these, so the boiler controls it and sequence seems fine valve opens pump runs boiler fires then over heats! All Honeywell controls, room stat, cylinder stat, timer, valves etc.

 

[Chuck]

Pump is wired to the boiler on these, so the boiler controls it and sequence seems fine valve opens pump runs boiler fires then over heats! All Honeywell controls, room stat, cylinder stat, timer, valves etc.

All good then.

Is the CH feed tank working correctly, i.e. not emptying when the pump starts and hence letting air in to form an airlock? Any 'inverted-U' sections of pipework that don't have bleed valves on them?

What model of pump and what is the height difference between the pump and the water level in the CH feed tank?

 

[ShaunCorbs]

Long shot check valve ??

 

[JE-P&H]

Problem solved! - Finally got to the bottom of this Monday morning the culprit being a faulty (brand new) pump valve despite being open the gate wasn't actually opening hence the no flow. Thanks to everyone for the suggestions got there in the end!!

 

[Old Account]

Thanks for letting us know much appreciated