Mitsubishi Ecodan ASHP

DavidAlgarve

I have just installed a Mitsubishi Ecodan ASHP and therefore the Tado bridge, Extension box and Wireless Thermostat which were used for the gas boiler are redundant. All radiators have manual thermostatic valves and these are now the only room temperature controls..

I don't think it is practical to try to use the Tado equipment to control the ASHP, but I wonder if it would be worthwhile to buy some wireless controlled TRV's and if so how do I implement it?

Would appreciate any thoughts.

GrilledCheese2

I’m no expert in heat pumps but I know enough about them that you don’t want to be using a smart thermostat to routinely switch them on and off. Otherwise you will have a low COP and a bigger electricity bill. So you’re doing the right thing by not using the existing Tado thermostat to control the ASHP.

If you want to independently control the temperature in some rooms then keep only the bridge and buy the radiator valves. The valves will connect to the internet via the bridge and will appear in the app, but obviously have no control over the ASHP.

DavidAlgarve

Hi Grilled Cheese, Thanks for your answer. I was thinking along those lines and wondering if the centrally mounted bridge could serve the majority of the radiators in bedrooms, kitchen etc.

Would I have individual temperature control on them? Home and away?

It is preferable to run the ASHP continuously even though we have a 100l buffer tank, but I have found that this results in the existing TRV's making too much noise when throttling back during the night time, so it would be handy to have a timed lower temperature setting in the bedroom(s)

I also wondered if I should use the wireless wall thermostat to control the two rads in the lounge, thus having the additional Tado app features

GrilledCheese2

For each radiator valve you can define a schedule and have the option to use home/away mode. And your current wall thermostat can be configured as a wireless temperature sensor and paired with one or two radiator valves in the same zone. Sounds like you’ve got some experimenting to do to find the balance between comfort and efficiency.

DavidAlgarve

Thanks again. What you describe is exactly what I was looking for, but wanted to check before buying some wireless TRV's.

I was a little surprised that there was no room control supplied with the Mitsubishi Ecodan ASHP and the only control is the circulating temperature to the rads which is currently set at 50C.

However, this is more than adequate and the house is warm throughout, possibly helped by having it running all day.

I have it timed off during the night because of the noise from the TRV's when they are near closing.

Happy Christmas to you and all Tado fans

ashtor

Im not a heating engineer but my understanding is that the Tado thermostat does work with the Ecodan as the ecodan does use modulation rather than just on an off. A couple of heating engineers have said that the old heat pumps used to just switch on/off the compressor but that constantly turning on and off shortens the life so newer units do modulate. How that actually works in practice I don't know. But am definately considering a tado setup mainly because its the only system which allows a room trv remote from the thermostat to automotically call for heat. Scenario where this would be useful at night in a room which needs to be at 18c ie a baby in the room and the rest of the house can stay unheated.

DavidAlgarve

I have made some progress on this after fitting 4 Tado TRV's.

The ASHP is now running all the time and there are a number of radiators which have conventional thermostats, to allow continuing circulation when the all TRV's are closed. I see no point in using the Tado wireless thermostat to control the ASHP and I am happy for the Mitsubishi equipment to control the temperature in the buffer tank.

My Tado wireless thermostat is used to control the 2 rads in the large living/ dining room and the scheduling is relatively simple with 5 temperatures throughout the 24 hours.

The other three TRV's control single radiators in kitchen; family room and main bedroom and the first two are straightforward, but the bedroom has been the most difficult.

The problem is noise, when you are asleep, as the water starts to flow when going from a low temperature, particularly if there is a big temperature difference. I am not quite there, but I have introduced short periods with small temperature differences and used Early Start.

After early doubts, I am very pleased with all the facilities that the Tado TRV's offer and I have ordered a further four which should have been delivered today.