@ChristopherS_OVO Well a week on and not much to report - the heat pump system is churning away, the electricity meter is whirring away happily and I am having to admit to a total defeat.

I have given up on the app - right now it is showing no information at all and there are no working controls. There is something very wrong with this app, my configuration, my hardware or some combination of all of those. Even if it is still trying to load data then (design suggestion) the fields and screens should still be there but greyed out, not just random permutations of screens, links and data that appear and disappear. I still don't know what a working system should look like and this has taken up way too much of my time.  I'll use HomeAssistant for some of this and the wall unit for the rest.

The good news is that I am assured that my system is responding correctly to everything except the app so I await OvO connecting customers to the new tariff with anticipation.

@ChristopherS_OVO It started working! At about 4:15 pm today the app suddenly started displaying energy graphs, the stuck features unstuck themselves, things like the number of hours are now going up and a few extra information fields appeared.

Someone obviously fixed something for which congratulations and thanks.

Next I need to try and understand the data ...

I thought this was worth posting - the system is set to a desired temperature of 20C between 07:00 and 21:30 then setback to 15 C. You can clearly see it doing that and just ticking over overnight.  The lounge dropped from 19.6 to 17.8 C over the setback period. (this is from HomeAssistant).

@ChristopherS_OVO Just an update for no particular reason … ASHP has been in for 6 weeks now, seems much longer. Teething problems seem (touchwood) to have resolved themselves, With the warmer weather heat pump is barely ticking over - between 3 and 8 kWh/day for heating and hot water and a heating COP between 5 and 7. I won’t have a proper indication of performance till the autumn. Unfortunately the first two weeks we were running (a cold April) coincided with having no energy data except the meter reading but there is a suggestion there that the electricity demand will go up sharply when the temperatures go down.

OvO send me periodic bulletins - they’re still sorting technical issues with Vaillant but expect to go live with the heat pump tariff very soon.

In terms of how the house feels we run it from about 7:00 till 9:00 then on setback overnight.  The house feels different because the temperature range from warmest to coolest is less than with the conventional central heating and we quite like it.  As I say though, time will tell when it gets cold.

@ChristopherS_OVO Another random update .. principal events to report are that the teething troubles with the app and data collection seem to have been sorted and that we are now seeing heat pump credits on our electricity bills. Just now they’re not huge because the system is hardly on but come the winter that will change with a vengeance. Thank you to everyone at OvO and Vaillant for their efforts here - this is exactly what is needed to encourage people to adopt this technology.

Hey @dr_dongle 

Glad to see you’re finally seeing some benefits after facing those tricky teething problems.

Thanks for popping that update on, we look forward to hearing how things go, especially as you head to winter and you’ll likely see that uplift in the credits.

Maybe I'm missing something but are the pipes in the “Monty Python” network you show now insulated?

Oh very definitely! This is it now. The uninsulated pipe is LPG to the house and the sharp-eyed will see a new yellow box which is a WiFi interface for a bunch of temperature sensors on the pipes and outdoors plus a changeover switch so I can run the boiler stand-alone under Hive if I need to.

A follow-on topic … the sensors are T1-T7 in the diagram below and report to HomeAssistant via WiFi. I’m going to put current sensors on the pumps as well at which point I can see exactly what the system is doing. I’ve already identified a couple of oddities in behaviour such as flow through the oil boiler loop even when the pump is off and a spike in hot water flow temperature daily which is more often than expected. I have also identified that the ASHP reference temperature sensor is not in the best place.

Hey @dr_dongle, 

Thank you for another really insightful update! Where are you thinking of moving the ASHP reference temperature sensor in relation to it’s current setup?

You are too kind!  The problem with the existing location is that though it faces north, a) it catches the morning sun and b) it is in what seems to be a bit of a heat trap, which is presumably why previous owners put decking there .. d’uh!. The ‘better’ location is just a few feet away round a corner and more shaded. There is a disused ventilation cowl there from the old boiler so I stuck the sensor under that with a piece of reflective foil over the top. 

There were a couple of surprises, obvious in retrospect: The current location is attached to weatherboard and the ‘better’ location is attached to brickwork. Though the ‘better’ location is cooler during the day is warmer for part of the night despite my mounting it on insulating board . The brick wall must soak up the heat during the day and re-radiate it at night.  I put a sensor on a long north wall and another under trees 20 metres away. The north wall was second warmest and the trees were coolest by quite a lot.

The temperatures follow broadly the same curves which probably means that none of this matters much because the system will adjust to compensate.  Warming from the sun does distort things though. My conclusion is that having the thermometer out of the sun is more important than having it pointing north and that mounting it on wood is better than brick. Just making a little reflective sunshade for the sensor may be all it needs. I’ll do that and see what happens.