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Overshoot/undershoot cycles

Posted: Tue Dec 07, 2021 3:37 pm
by deendel
I had a new boiler, new TRVs and Evohome installed in the summer. We had a long time suffering hammering TRVs, but now that's solved I'm looking at the overall performance of the system.

I've hacked together some monitoring of the temperature in each room and the boiler demand (attached). You can see that the temperature control is pretty bad in most rooms, oscillating over a period of about 2 hours.

Any ideas how to get the system to control the temperatures better?

Is it worth trying to reset the learning so it forgets things it learnt while the system was set up differently? (Can I do that without forgetting the schedule etc?)

Notes for interpretation
Hallway TRV#1 is actually the Evotouch sensor, TRV#2 is the main radiator, TRV#3 is actually in the WC

Advanced Load Scaling is on Full.

Boiler is a Worcester Bosch 8000 Life 45kW combi, using TPI control

Re: Overshoot/undershoot cycles

Posted: Wed Dec 15, 2021 1:31 pm
by Richard
deendel wrote:I had a new boiler, new TRVs and Evohome installed in the summer. We had a long time suffering hammering TRVs, but now that's solved I'm looking at the overall performance of the system.

I've hacked together some monitoring of the temperature in each room and the boiler demand (attached). You can see that the temperature control is pretty bad in most rooms, oscillating over a period of about 2 hours.

Any ideas how to get the system to control the temperatures better?

Is it worth trying to reset the learning so it forgets things it learnt while the system was set up differently? (Can I do that without forgetting the schedule etc?)

Notes for interpretation
Hallway TRV#1 is actually the Evotouch sensor, TRV#2 is the main radiator, TRV#3 is actually in the WC

Advanced Load Scaling is on Full.

Boiler is a Worcester Bosch 8000 Life 45kW combi, using TPI control
evohome takes a bit to settle down (circa 2 weeks when you start using it properly). I would consider room sensors if you want more accurate room control. Also consider reducing your boiler flow temperature, range rating your boiler and getting your heating system balanced correctly. :geek: