Every night at random times we are getting the error code E912 fault so we wake up to no heating. Hasn’t been much of a problem as it has been mild and engineer is coming out on Monday to fix. In the meantime, we got back from New Year celebrations this morning at 3.30 and noticed pump was still running despite fault code (or more accurately that is the cause of the fault code). Temperature of DHW had risen to 55 degrees despite our setting of 47.5. I wonder how high it would have gone without intervention.
page 43 of the manual says
912 Normal flow rate error- in case of normal flow rate in 10min during water pump signal is OFF
Looks like the pump is staying on too long for some reason. This is one for the heating technician.
PS I had this when the comms control cable to the Grunfos pump was disconnected. By default the pump stays on. That may be the problem but I am no expert.
Yes, make sure you have PWM cable connected properly. If heat pump registers circulation pump running when it should not it will throw this error. My genius installers (who installed this pump for the first time and haven’t had an idea there must be external circulation pump installed) didn’t bother to connect PWM cable at all (because again no idea about PWM) so all the time I was getting this error.
OK thanks for the advice. Overall I was very impressed with our engineer who is an authorised installer for Samsung, Vailant and Dalkin and does lots of commercial installs of aircon as well as domestic heat pumps. I’m sure he’ll sort out on Monday.
One interesting observation is that despite living in a large Victorian house with little in the way of energy efficiency measures the house hasn’t been going below 17 degrees despite the heating going off around midnight each night. Last night the outside temperature was down to 1 degrees.
I wonder if this might also be related to our Drayton Wiser system that we retained for most of the radiators. The heating system is split between ground floor and first. Downstairs is run off the Drayton master thermostat and upstairs is run off a Honeywell thermostat. For the latter we have set the radiators to be turned down low after midnight and then to resume full heat at 4am to coincide with the Octopus Cosy tariff. I guess the interaction of different calls for heat may confuse the system.
I left one of my upstairs Wiser TRVs on all night and reverted to a manual control of main upstairs thermostat and for the first time in a few nights I didn’t get the error. Seems it might be getting a bit confused.
I’m abroad on holiday and Smart Things has indicated my heat pump has gone off again for second time in 10 days. First time my son happened to be visiting, it was the same error again and he reset. This time it looks like we’ll come back to a very cold house.
Given that reset is so simple, is there no way to be able to control the controller remotely, even involving an additional bit of kit?