Glowworm Cxi combi probs

[Plucky]

A mate has had a plumber come in and move two rads. My mate has turned heating on and its not working, he isnt sure if the guy tested it before he left.

Boiler was installed 18 months ago and by a cowboy no paperwork filled in and it hasnt been notfied!

Anyhow when demand for heating the boiler fires for a few mins, reaches temp and goes out. Flow from boiler is hot for the first 6-12 inches out the boiler. Obviously no circulation and water just whizzing round built in auto bypass.

Now Glowworm are saying its likely to be a blockage but am I right in thinking it may be fault with diverter valve. I'm an installer and dont get involved witgh much servicing/breakdowns and certainly havent worked on these boilers before.

 

[Kip]

Won't be the diverter valve as the flow is circulating as you say for 12-18 inches until the bypass then making its way back, by the sounds of it you have yourself a fairly large air lock...

Best way i find to sort these out in a sealed system is to drain it off, close all the radiators off, pump the system upto 2 bar, open one valve on a radiator bleeding it until water comes out then after that open the second valve on that radiatior. do this around the whole system, it should shift it. It would be useful to be two of you doing this, one keeping that pressure upto 2 bar and the other bleeding and so on. Expect some clanging pipes

 

[Plucky]

Won't be the diverter valve as the flow is circulating as you say for 12-18 inches until the bypass then making its way back, by the sounds of it you have yourself a fairly large air lock...

Best way i find to sort these out in a sealed system is to drain it off, close all the radiators off, pump the system upto 2 bar, open one valve on a radiator bleeding it until water comes out then after that open the second valve on that radiatior. do this around the whole system, it should shift it. It would be useful to be two of you doing this, one keeping that pressure upto 2 bar and the other bleeding and so on. Expect some clanging pipes

I really dont think its an airlock. Its a sealed system and the pump is circulating water through heat exch and DHW heat exchanger. And the reason the pipe is getting hot is just conduction of hot water its not circulating. The Auto by pass is inbetween the pump and the Diverter valve so it would circulate via the bypass even if diverter shut off.

Spoke to glow worm and they suspect a blockage somewhere. Im dubious about this as well as its all new pipework, new rad and it was flushed after installation to remove flux residue,

 

[Puddle]

Should think it is the divertor valve stuck or the inline filter blocked,which I believe is on the flow pipework from heat exchanger,were connects to plastic block in lower part of boiler

 

[so-solar]

check the simple things first mate! Is every valve underneath the boiler open? are the trv,s 2 way? is every rad full of water? is the pump actually working? check the impeller is spinning! Are there any other valves on the system that were shut during install and forgot about? are the rad valves actually open?

why would the diverter valve stick but the flow and return pipes still get hot?

 

[Kip]

why would the diverter valve stick but the flow and return pipes still get hot?

Thats what i was thinking, there must be somewhere reducing/stopping the flow of water. blockage, air lock, valves, something is stopping that water from moving around and its just getting tooo hot and cutting out.

 

[Puddle]

?

why would the diverter valve stick but the flow and return pipes still get hot?

These posts are getting like chinese whispers,flow and return are not getting hot

Maybe when boiler replaced ,system not cleaned,along comes some lad,drains system and does a nice job of fitting two radiators
but as system dirty,black rubbish has dryed out in the plastic divertor valve,causing it to stick when refilled,therefore strip out valve and clean,then get system cleaned and inhibitor added otherwise your mate is going to end up with a new boiler in four years

 

[Plucky]

Flow and return pipes are not getting hot! The flow side of the boiler is hot, Believe boiler is pumped on the return but could be wrong. So if divertor shut and water going round bypass the flow pipe would get warm via conduction