Potterton Suprima 80

I have a simple problem. Potterton Suprima 80 boiler. Problem since new 1 year old. The boiler does not stay on long enough, I have temp guage on the outlet copper pipe from boiler newer goes much above 60degree. I have had the circuit board changed, the temp sensor changed, as recommended by various plumbers. Yet I have the same problem. The temp control knob is on max. The same problem, the boiler stays on for 2mins then goes off. Why does the dam thing not stay on!!!
Anyone who has a solution, or have had similar problem most welcome to contribute.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Michael wrote:

Check that the primary water is actually able to flow well - stuck pump?
--
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

No, the pump is setup for fast speed, if its med or low the heating just gets warm. Only on fast pump does the rads warm up. There is no air in the system as the plumber has removed it all. Still same problem Temp control knob on boiler is set to max and the boiler does not stay on enough to heat the water out from boiler above 60degree.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Michael wrote:

I'm sure others have seen this fault before. The temperature sensor(s) may be out of specification. I'd go for exchanging one of those first you could also compare the replacement unit to the installed unit to see if that is the problem.
--
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

is there any chance that the temp control knob device is faulty?. I know i had replaced the circuit board, but the temp control knob itself is that on the circuit board or is it a seperate device I think its called a potentiometer!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It's on the back of the control panel, the knob's on the front. Just next to the reset switch which you should be very familiar with if you're the proud owner of a Suprima. I think that Suprima temp sensors are very prone to cracking
--
geoff

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.