Intermittent over heat

[Millsy 82]

I installed a boiler 10 months ago and it started tripping the over heat so I popped out and the pump had had it (customer refused to have the controls replaced) so I replaced the pump and over the next week it tripped out once so I popped out again and tweaked the bypass valve and again it has tripped once over a week and a bit.

It is on a y plan with all trvs but with a bypass so it should be OK as when they all shut down it shoots through the bypass.

Any ideas?

 

[Howsie]

How close to the boiler is the bypass?

 

[oz-plumber]

Check to see if the boiler is modulating down as the return temperature rises.

Had a new boiler recently that wasn't modulating and was running at full gas constantly.
Turned out to be a faulty sensor.

 

[Millsy 82]

Check to see if the boiler is modulating down as the return temperature rises.

Had a new boiler recently that wasn't modulating and was running at full gas constantly.
Turned out to be a faulty sensor.

Should of said its oil

 

[Millsy 82]

How close to the boiler is the bypass?

A meter or so

 

[Leo21]

If it's on a y plan, the three port acts as a bypass anyway.

 

[lame plumber]

turn down the boiler stat for starters and have a look at how clean tghe system is, a good flush will help if it has worked fine in the past.

 

[Best]

Check the actual temperature of the flow when you leave the boiler to run up to heat.
You could have a faulty control stat, even though new. As it is only 10 months old get the manufacturer to sort it if your work is ok.
I find a lot of Warmflows stats were faulty and if control stat turned fairly high the limit would cut out.