stove now running hotter than before, but why ?

hi,
had wood burning back boiler for over 30yrs, had 2 in that time
first one run lovely and hot, but second one was bigger but never as hot
both connected to the same pipe work (flow pipe and a return pipe with a vent)
this week I fitted a direct vent pipe to the boiler as well as the flow pipe, return pipe with a vent (so now boiler has 3 pipes out the back
when I lit the fire the other night it now runs a third hotter than before (tested using thermo laser gauge) and radiates heat like the old one did
I'm using the type of firewood
why would adding a direct vent make this change ?

Those laser guided thermometers can be very inaccurate depending on the colour and material of what you're trying to measure the temperature of. Copper in particular can be very misleading. Stick some black duct tape to it though, and you get a more representative reading.

It is an issue of emissivity!

Nozzle

yes they can be inaccurate, but the heat was also radiating our into the room, which it never did before I put on this direct vent pipe

goateater said:

hi,

direct vent pipe to the boiler as well as the flow pipe, *return pipe with a vent*

why would adding a direct vent make this change ?

Click to expand...

because the vent should have been on the flow That's assuming you're talking about a gravity circuit

sorry got the terms the wrong way round,
thought flow was feed into the boiler
and return was the hot water coming out

so the flow coming out of the boiler (Hot) has a vent on it
and the return (cooler) goes into the boiler

so its still the same question just the terms I used need to be reversed