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Brian, Plumber
Category: UK Plumbing
Satisfied Customers: 845
Experience:  16 yrs. experience as plumber, including full bathroom and kitchen installations.
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I have just installed an oil boiler a Worcester bosch heatslave.

Customer Question

I have just installed an oil boiler a Worcester bosch heatslave. The cold feed is OK, and the hot line is full, but the CH system won't fill, i.e. when I try to bleed, nothing comes out. Most of the rads are disconnected for decorating.
Submitted: 2 years ago.
Category: UK Plumbing
Expert:  Brian replied 2 years ago.
Hi, my name is***** have been in the plumbing & heating trade for approximately 15 years. I will be helping you today.
Heatslave Combi Boiler is this correct.
Can you hear the water running into the central heating system when you open the filling loop.
if you can! Have you got boiler isolation valves installed ? if these are turned off it will allow the boiler to fill but the rads wont.
Customer: replied 2 years ago.
I will need to fill as you suggest, i.e. isolate the boiler. The problem is Drayton TRVs, old ones and they don't shut off. I have blank caps now but also as this is a 10mm system, the old 15/10mm reducers are no longer fit for purpose, so I am currently draining down the system so I can retrofit new valves and reducers. When I have done that, and can fill the system, I will get back to you. We also had a scheduled power outage today that ended up lasting 6 hrs, so that did nothing to help the work. I will be in touch.
Expert:  Brian replied 2 years ago.
I dont quite understand. I thought you were unable to fill the system after changing the boiler. Basically you need to use the filling loop making sure all isolation valves are open and this will then fill your heating system.
Yes by all means come back when your ready no problem.
Have you always had a combi boiler or is this replacing an old vented system with a cylinder?
Customer: replied 2 years ago.
Boiler full but still won't fire. Error message F9. I closed off the feed/return to the rads so maybe the pump is confused and causes the shut down. It could be I haven't primed properly. Any easy way to prime? I tried a small vessel (HP sauce bottle - clean - small nozzle) but most went on the floor. I thought of a pipette but is there an easier way? I have access easily only to the end of the flexible hose that connects to the feed, not the end on the burner so I need some means, I think to inject fuel into the line.
Expert:  Brian replied 2 years ago.
Hi Is this a brand new boiler?can you take a photo of the Display that states F9 and of the burner please.You need to loosen the bleed nut on the pump slightly and push reset when oil squirts out of the bleed nut tighten it up and it should fire. The boiler may need resetting quite a few times depending on how far the oil will need to travel.