Hitachi Yutak and system controller

[tsh]

A selection of Heat energy out vs electric power in.



Electric energy captured using android Energy Meter app, heat energy captured with an out-of-cert PolluCom E/S




I have also determined that the default controller settings I had were way off. There are settings for flow temperature floor/ceiling - these just act to clip the temperature. The weather compensation setting started out at about 1.7, I now have it at 0.5 (Ambient -2, Room 21 gives about 40C flow) with the room compensation set to 5 at the moment (allowing for a faster ramp up of temperature, then the flow backing off as the room approaches the setpoint) Without this, the room was overheating as it would be calling for a flow limited only be the ceiling until the room stat was reading a degree or two above the setpoint.

[tsh]

Weekly electricity consumption of house vs degree days. Starting in October 2011, showing storage heaters before installation (with poor control), period through December including installation, and stable period from Jan 2012 (still tweaking settings but house is warmer than in October)

[tsh]

Just got home after a week on holiday to find the RCD on the heat pump has tripped, and after resetting it I get nothing from the heat pump. Whilst i'm waiting to get in touch with the installer, any suggestions about what I can try? I get mains at the heat pump, so I'm guessing its an electronics fault needing a new PCB

[wookey]

Oh dear. Nice graphs though, which I had missed earlier.

The graph of power consumption vs degree degs seems remarkably linear. There ought to be a big discontinuity on change over from storage heaters to ASHP, shouldn't there. The slope could be said to have improved somewhat, although the dtaa is quite noisy so it's hard to say for sure.

[ecogeorge]

Just got home after a week on holiday to find the RCD on the heat pump has tripped, and after resetting it I get nothing from the heat pump. Whilst i'm waiting to get in touch with the installer, any suggestions about what I can try? I get mains at the heat pump, so I'm guessing its an electronics fault needing a new PCB

My guess would be a pump to earth fault , -any heating elements within the heat pump assembly?
just my 2p.

[tsh]

Fault was a blown 5AT fuse on the main control board in the unit, but there is a compressor heater which is a possible candidate for water ingress and an earth fault. Will try and check how much current this fuse is actually taking over easter.

The graph data is a bit light on data with storage heaters from the end of last year, and it's not a a:a comparison since the house is probably more comfortable now (and my storage heater setting tended to lag the changes in weather). I'll update again once I have some warm weeks on the chart. I also have deviation from a straight line fit over time which shows that the controller setting changes I made to get better weather compensation saved me something like 30kWh/week.