Thermocouple


Ferroli Optima 701 boiler model. Got a problem with central heating...the boiler is failing to fire...or firing for a few seconds then dying (this is on constant 'heating' with the timer overridden). Water through hot taps is generally OK, though sometimes it misfires as well. The thermocouple looks a bit 'bright' through the viewing window. Does this seem likely to be the problem? Everything else seems fine, no noises or problems when the boiler's actually running. TIA
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What do you mean 'the thermocouple is a bit bright'? I presume you mean the pilot light? The only way to check the thermocouple is to measure the small voltage produced by it when it is heated by the pilot. From memory this is about 30-40 millivolts.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

But more likely to be the divertor valve.
Adam
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Also check that the pump is working when heating is on.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John G wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ARWadsworth wrote:

Cheers.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Farmer Giles wrote:

Instead of being black/grey, it's like when you blow out a match and it stays red for a few seconds, but it's like that all the time. Carbon?
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.