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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.

Im building a new house and need to purchase a ASHP, looking mainly at Vailant because of the OVO 15p per KW offer they have for their customers (which I'm one of)

In order to receive this offer, do I need to buy the Vailant heat pump from OVO or can I get it from a certified MCS installer and still claim the new tariff? I will also be purchasing the Gateway add-on, is this the only requirements?

If not, then maybe I will look at other ASHP rather than just the Vailant range

Any help appreciated!

No need to post twice: you’ve already had replies in your own thread :)