6kw R32 Ecodan ASHP on oversized rads

[Timbones (Tim)]

@kilowatts.io

Given my system is sized for -2C, I’m thinking it’s probably oversized.

What makes you think it’s oversized?
What’s your actual heat loss at -2C?

@kilowatts.io

on oversized rads

Are all the valves open? Have the radiators been properly balanced?

@kilowatts.io

But wondering if I the patterns above look good/bad

Looks okay, though cycling sooner than I would expect and COP is less good on those subsequent cycles. There are some settings you can change to adjust the overshoot (but only when using Auto Adapt):

Anyone monitoring a new R32 Ecodan?

This bit of the FTC6 manual… [image] …has the following footnotes: *8 Valid only when operating in Room temp. control mode. *10 Valid only when operating in Heating room temperature. *15 When DIP SW5-2 is set to OFF, the function is active. Where DIP SW5-2 is for “Advanced auto adaptation” and is on by default. Unfortunately my system is in a tiny airing cupboard and reports the “room” to be 25 degrees all day, so room mode no use to me but maybe it’ll help someone else.

If oversized, it might be worth trying Quiet Mode (on FTC6), which reduces that maximum power output, raising flow temperature less quickly.

Do you have access to the flow rate? Can you calculate heat output? This thread might be useful: Estimating Power from MelCloud data - #2 by Timbones

@kilowatts.io

whether I might want to try controlling the flow temp manually

This is possible, but needs very close monitoring and control, and I found Auto Adapt to work way better (and more reliably) than anything I came up with.