Central Heating Query

Forgive me if this is a common question, but I would like some advice about my central heating system.
I can't seem to make the heating come on beyond a certain temperature. If I set the thermostat to, say, 30 degree (max), I'd expect the radiators to be on all the time (I don't think it can be that hot in any room).
Instead, the radiators stay lukewarm. The only indication I have (which may be co-incidental) is that I ran the hot water until the tank was empty, at which the hot water (boiler) started working to re-heat the water and the radiators started to get warm.
However, this didn't last that long and they soon returned to being barely warm to the touch.
I realise this isn't much to go on, but any advice would be greatly apprecaited.
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

enough to break the NSL, any advice?"
i.e. no information as to what boiler, configuration, controlled by a room stat or what ... if you get my point
--
geoff

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 23 Dec 2003 15:18:14 +0000, Stuart wrote:

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

From the symptoms you describe, it could possibly be the zone valve on the heating circuit which is at fault. The zone valve has a directional flow and any backward flow might just be enough to allow heated water from boiler to flow backward through the heating circuit and make the radiators luke warm. When the hot water system opens, the water is then given a less resistant path to flow back to the boiler and the radiators heat a bit.
Have a look at the zone valves on the heating circuit (it should look like a rectangular shiny tin can on one of the pipes) and you'll find a lever arm on one end. Slide the lever arm along until it reaches the locking clasp in the wall of the valve cover. You should feel slight resistance against your finger when doing this.
Once you have the valve locked open, turn the heating on and see if the radiators get hotter.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.