filling vented central heating after draining

9 Aug 2009
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United Kingdom
Hey I have drained my vented central heating system to replace some rad valves for trvs. I want to know when I refill the system when do I turn the pump on which is on the flow pipe as it leaves the boiler. Do I do this after I have filled all the radiators or as soon as I let water back in to the header tank?
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switch nothing on yet

open feed and exp tank

lock open motorised valves, fill and vent rads,fill and vent pump, fill and vent cylinder coil, unlock motorised valves

turn on heating and hot water and give everything another vent

Thanks there are no motorised valves the system just does one C/H system. The hot water is heated by a separt instantanous gas water heater. So do I fill the header tank first, then bleed the radiators ( downstairs first). After that do I start the boiler or the pump next the pump has a separtet switch.
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You just turn the water back on at the header tank and fill the rads from the bottom up. Turn on the pump then boiler and recheck for air.
I think you should spend a bit time or money and hook the pump electrics up to the boiler :idea:

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