WB Greenstar 30Si - no CH but hot water is fine

[Agile]

Yes, it does sound like the diverter is jammed although as some heat is going towards the rads its obviously leaking to an extent.

But that would mean the pump IS working in spite of the OPs thought that it isnt.

Tony

 

[HotrodCJH]

Sounds like an air lock on the return side of your heating circuit to me.
Does the pump get v.hot when its running on heating.
Try taking a radiator off and blasting some water through from both rad valves. (Fill the system at the same time if its a sealed system).
Put the rad back on and see if you have any flow though it.

 

[boilerdoktor]

i'm gonna put money on this one!

If he's checked for air, I GUARANTEE it will be the stepper motor stuck in the h/w position, sends h/w around the boiler and cuts off because it's going nowhere! and reaches temp! had it before at this time of year!

Poster, remove casing and look to the right hand side there may be a green cover on a small motor to the right of the pump!
Is it in the upright position? If so its stuck in h/w mode. Slip it out ( no screws etc) and turn the boiler off and then on, does it move up and down and settle in the mid position. If it doesn't move up or down it is seized!

 

[Agile]

How can you "put money" on that when you dont give your name and address or any other identification?

 

[kevplumb]

How can you "put money" on that when you dont give your name and address or any other identification?

i notice your name isn't in that advertising billboard you call a "profile either

 

[PAB1968]

Thanks to all who replied. You were all wrong unfortunately.

Do you know what it was?

Well the plumber who serviced the boiler in mid August also emptied the Magnaclean cartridge which is located under the boiler. But apparently the dozey f***wit forgot to reopen the valve back into the boiler. So the heating kicked in but the water could not return to the boiler so the CH shut down.

Luckily the WB engineer didn't charge me for a call out.

How the original guy is Gas Safe registered when he shows such basic incompetence is beyond me!