Worcester bosch Combi 30i

[auw]

Hi all,
I'm new to the forum
I have just installed a above mentioned boiler myself. Incoming gas 22mm, heating flow and return 22mm as required. There is a remote thermostat as well. House is two floors so I have two return and floe circuits serving the two levels and both joins just before connecting to the boiler
I get hot water all well and fine
However the CH does not work. The boiler starts runs up to about 50 on the boiler reading and cuts off and the water does ot seems to circulate either. Not error messages on boiler display either. Everytime I restarts the boiler it runs till it hits 50 and cuts off. If the temp is already around 50 when I hit the restart, nothing happens.
But the temp goes above 50 when using hot water.
Please help,
Thanks and regards,
AUW😕

 

[moogwai]

have you opened valves on flow and return?? you'd be suprised how many people do this!

 

[auw]

Thanks,Yes I have all the valves. I have had it running/circulation couple of weeks ago but then had to change some pipe work and also had the external thermo connected.
As I mentioned, the temp does not go above 50 and there is no faults being registered on the boiler.
many thanks,
A

 

[oldplumber]

isthe pump running ok, it needs bleeding after a drain down, if not it could run dry and seize in the worst case scenario. Otherwise check the external thermostat is set up properly, if its a modulating sensor and its hot outside, its job is to prevent wastage and control boiler output to the level required based on outside temp, therefore hot outside dont need to heat inside, so it could all be working ok!!! Have a read of the instructions and it may become clear

 

[Puddle]

Was the system cleaned correctly when you replaced the boiler,if not when you drained down,any black rubbish could have dried in filter or diverter section/blocking or sticking internal parts maybe

imho

 

[moogwai]

could trying disconnecting external stat and see if it runs then.

 

[Billy Bob Bob]

think you have a pipework problem,did you by any chance remove a cylinder and get the flow wrong?

 

[jambo]

flow and return crossed over

 

[auw]

Hi all and thanks for the response so far,
Most of the pipes are new and all of the radiators are new. I have flushed it simply by circulating water and adding the flushing agents but could not have flushed that well as the circulation really has not happened due to the problem that I'm highlighting. But there can't be too much dirt as the system is new and I have fitted a Mag filter on the end of return.
I have checked the returned and flow and there is no short circuit. The pump is seems to be running fine. What I did was to disconnect the Flow NTC (not sure what this is but it is a sensor on top of Heat Exchanger) and the pump runs. You hear and feel the hot water passing.
Could it be the diverter valve, as I get hot water but no flow in the CH? How would I check this.
Any thoughts? Thanks and regards

flow and return crossed over

Are you certain, is this a typical symptom? I will check again. But I do have two circuits, ground and top floor. Even if one is crossed the other should work ok, thus the system should run, please confirm, thanks

 

[wnjswozo]

sure theres not a non return valve on existing pipework,wont be boiler,there has to be a fault with pipe layout,blank off one of the floors and try it

 

[auw]

sure theres not a non return valve on existing pipework,wont be boiler,there has to be a fault with pipe layout,blank off one of the floors and try it

Please bare with me here as this my first boiler,
As I have mentioned, when I disconnect the Flow NTC(?) the pump runs and the water the CH circulates, does this make any sense? Thanks