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no hot water but ch on

Postby baikelman » Sat Aug 04, 2007 4:17 pm

drained ch system moved radiator from in front of window to other wall impending french doors tues. turned drain valve off put radiator bleed valves back in went in loft and untied ball cock waterstarted filling tank went downstairs and waited rads filled up and bled the system of air turned gas on and pump put ch on and every thing seemed ok rads hot now next day i have found out i dont have hot water how ? system is thorn gloworm back boiler with 7 rads any advice will be wellcome
many thanks baikelman
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Postby htg engineer » Sat Aug 04, 2007 6:12 pm

Sounds like an airlock, are there any vent points near the tank or cylinder ? if so open these til water comes out - with heating turned off.

If no luck you could try draining the system again and hopefully the primaries will fill up this time. If not there's a couple of thing you could try.

1- crack open the 1" nuts on the tank or cylinder, these are the primaries, flow and return. This should let any air escape, same as venting a radiator - wait for the water.

2 - get a heating engineer to remove fire and pull boiler stat, this will boil any any airlocks out of the system.
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Postby GeckoGas » Sat Aug 04, 2007 7:47 pm

You're probably on a gravity system and the cylinder may have air locked.... Carefully crack the top joint on the side of the cylinder to see if any air comes out.
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Postby baikelman » Sun Aug 05, 2007 7:12 pm

drained system again and filled it up slowly all afternoon bled radiators downstairs then up turned on hot water fired up boiler half an hour radiators all hot upstairs try taps still no hot water. you say crack open the 1 inch nuts on the tank as far as i can see theres top middle or bottom on the tank would it be possible to fit a self cutting washing machine tap/connector to the top pipe on the tank to vent it or am i not on the right track its doing my head in now been on all day got nowhere any advice will be acted upon.
many thanks to all who have posted
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