No central heating

I have a glow worm fuel saver 25-30 boiler. Its fires up ok to give me hot water but I cant get heat to any of my radiators. Is there anything easy I could check without blowing the house up before I call an engineer?
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Check that the control unit is making good switch connections - when you switch the central heating on and off, does the display change accordingly? If not, the switch connections may not be making properly, and you need to replace the control unit.
If that's ok, check that the motorised servo switch that switches between hot water and central-heating is not corroded or limescaled up and is free to move.
It will probably be near the hot-water tank, so most probably in the airing cupboard. There will usually be one pipe going in - from the boiler - and two coming out - one to HW and the other to CH - and in response to electrical signals from the rest of the system a servo motor inside the cap rotates the valve to connect each output in turn to the input. The spindle of the valve may protrude through the surface of the cover, and there may be a depression on the top of it that you can put a coin into and twist it to free it. Be sure to twist in same the direction of any arrow on the cover.
This may be sufficient to get it going for the moment, but it's probably a sign that your system needs maintenance, probably at least descaling, and probably replacemet of the servo switch. In time the cogs on the motor get worn away, and in that event the entire unit will need to be replaced.
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On Sun, 26 Sep 2010 19:39:14 +0100, "tomm"

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On 26/09/2010 20:01, Java Jive wrote:

Let me make it absolutely clear - you do NOT need a new boiler - whatever the gasman says!
Andy
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Ha Ha.. thanks !
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