Ecodan Zones/Wireless controller
Hi, I've recently moved into a new build which has an Ecodan PUZ-WM60VAA set up with DHW, Zone 1 > UFH, Zone 2 > rads.
There's one Heatmiser stat for the rads upstairs. UFH has stats in each room.
This is obviously setup like an old-school boiler, inefficient for a heat pump and leads to short cycling.
I purchased a couple of the wireless Mitsubishi stats and set them up, put the system into room temp mode (auto adapt?). However, I soon learned that the Heatmiser stats do actually call for heat and the system will not stop heating until it hits their limit, even when the wireless stats are showing a temp higher than the target.
I disabled 2 dip switches (SW2-1 & SW3-1) which prevents the stats controlling the heat and just act as pump control. This seems to work for the UFH however, Z2 will not heat independent of Z1 and with Z2's pump running will not put any heat into the radiators even while Z1 is flowing at 40c.
It seems the solution to this is: "For 2-zone temperature control, check DIP SW2-7 is set to ON (2-zone temperature control) and DIP SW2-6 is set to ON (With Mixing Tank)"
These are both off, I'm assuming I don't have a mixing tank and cannot just enable these?
I'm looking for a solution, maybe I need to hound the developer?
Tank image:

There’s quite a lot going on here, so we'll try to break it down with some unofficial insights from Mitsubishi. It sounds like your system is set up with two zones at the same design temperature rather than two zones with different temperatures. If that’s the case, SW2-6 & SW2-7 (which are for systems with a mixing tank) wouldn’t apply here. Instead, it seems SW3-6 is managing the two zones with the same temperature settings, and that’s correct for your system as it stands.
When it comes to third-party stats like Heatmiser, they usually work best when the Ecodan’s weather compensation is set up properly. The stats can then manage room temperatures and schedules. One potential tweak might be to check if the Heatmiser stats allow you to adjust the hysteresis (basically the delay between on/off signals). Widening this could help reduce short cycling. Another workaround some people use is combining zones or removing actuator heads to simplify the system and move towards an open-loop design, which can also reduce cycling.
For the Mitsubishi stats, Zone 1 should be fine in Auto Adaptive mode, but Zone 2 has to either follow the weather compensation curve or run in fixed flow mode. To get Zone 2 heating independently, you’ll probably need to look at what’s controlling its pump. It might require adjusting the signal cables or wiring, but it’s hard to say without seeing the full setup.
At this stage, it might be worth getting a heating engineer to take a closer look – they’ll be able to advise on pump controls, wiring changes or any other tweaks to get everything working smoothly. Mitsubishi’s Homeowner Helpline (0161 866 6064) could also be helpful for further advice.
Also, this video might help:
Get a copy of The Ultimate Guide to Heat Pumps
Subscribe and follow our Homeowners’ Q&A heat pump podcast
- 26 Forums
- 2,221 Topics
- 49.3 K Posts
- 126 Online
- 5,881 Members
Join Us!
Podcast Picks
Latest Posts
-
RE: How good is the app support for your heat pump?
It looks quite interesting and, like you, I'd only want...
By Sheriff Fatman , 2 minutes ago
-
RE: Grant 13kW Aerona3 - issues getting zones to temp
This is broadly what I remember from earlier and what w...
By JamesPa , 17 minutes ago
-
RE: Electricity price predictions
As far as I can tell it's not really infrastructure upg...
By Scalextrix , 30 minutes ago
-
We get a lot of reports here from people who are having...
By JamesPa , 38 minutes ago
-
RE: Large heat pump options for church building
We install mostly A2A for churches and village halls, o...
By dgclimatecontrol , 1 hour ago
-
RE: External wall insulation - your experience
So our house is in SE England. We mainly had mixed w...
By Batpred , 10 hours ago
-
RE: Should Our Water Circulation Pump Be Configured to Run All The Time?
@steelbadger lol it just made the rest of the house hot...
By Grantmethestrength , 10 hours ago
-
RE: 5 Star Service from Havenwise
@majordennisbloodnok and @benson Good suggestion! We'll...
By HCas , 12 hours ago
-
This is an important and relevant topic of discussion i...
By wully , 12 hours ago
-
RE: New Fogstar 15.5kWh upright solution
It could be an app working via Bluetooth or windows sof...
By Batpred , 13 hours ago
-
RE: Midea ASHP – how to set weather compensation
@pash44pump - pull the data from the data loggers and s...
By cathodeRay , 14 hours ago
-
RE: Pump and Esbe mixing valve for UFH
So my next question is about calculating pressure loss ...
By AndyCoo , 16 hours ago
-
RE: Low COP and unevenly heated rooms with 12kW Samsung AE120MXTPEH / AE260TNWTEH
Im going to try to take a practical approach to this, i...
By JamesPa , 20 hours ago
-
Even that may not be enough. Air can still collect, it...
By JamesPa , 20 hours ago
-
RE: Havenwise App Help & Forum Support – Get the Most from Your Heat Pump
@hcas Thank you.
By Morgan , 23 hours ago
-
RE: Say hello and introduce yourself
There are few heat-network schemes in UK @chris12 but I...
By Transparent , 24 hours ago
-
RE: Aira Heat Pump: Stylish Scandinavian Heating
@steelbadger really interesting to see an Aira unit on ...
By MikeH , 1 day ago
-
RE: Widespread failure of insulation installation
@jeff Along with a phone-in on BBC Radio Four today, mu...
By Toodles , 2 days ago
-
RE: What is the Heat Geek Guarantee?
@editor Thanks Mars, it is encouraging that Heat Geek a...
By colinc , 2 days ago
-
RE: Renewables & Heat Pumps in the News
Love the thought of it! simplification and sometimes me...
By Batpred , 2 days ago