Dux Airoheat Heat Pump

This is a guide to the spare parts and servicing of a Dux Airoheat. These are the majority of issues that arise with the product from a plumber with a restricted electrical license perspective . All other issues we would recommend a refrigeration mechanic to attend to or depending on the age condemn the unit “beyond Economical Repair”.

Airoheat Spare parts

Airoheat fan

Airoheat fan old stye $200 Airoheat fan new style $210

Airoheat fan is mounted a little differently to other heat pumps in the market being mounted horizontally on top of the heat pump. This unfortunately allows water ingress through to the bearings of the fan. This causes failing of the fan over time and sometimes a swirling noise or metallic clunking sound.

Failing of the fan can cause issues with efficiency and even cause the top of the Airoheat to ice up. I have literally had the whole top of the heat pump turned into a block of ice and need to be thawed out to allow any works to be done. The top of the heat pump icing up can also cause issues to the hot logic with water ingress. Please check this if this has happened as you are likely to get caught out.

Replacement changes from model to model. The first airoheat had a separate capacitor for fan that had to be fitted though this was eventually superseded to having a capacitor in built into the hot logic.

This style had 4 wires that were all colour coded connecting to push style connector. Unfortunately when replacing the fan you need to use the existing connector that was on the old fan.

The newer style fan is a much easier replacement. The fan pushes onto a plug on the hot logic box and has a small back nut for tightening.

Airoheat Hot Logic

Airoheat old style hot logic $210 Airoheat new style hot logic $210

Hot logic rain cover kit $75 (Does not include hot logic)

Dux Airoheat hot logic mostly has issues caused by water ingress.

Although there have been many many series of the Airoheat logic there are really 3 different types.

1st style

* Had no built in capacitor for fan

* Has issues with all three sensors entering through one cable gland. Silicon was then placed around the cables for added protection. Unfortunately this silicon didn’t work very well and the logic had major problems with water ingress causing burnouts to the logic.

2nd style

* Had capacitor for fan built into logic

* Main issue was still water though not as bad as the last style. Dux have now fixed the issue of the 3 sensors entering through the 1 cable gland have now been separated. Dux tried to further fix this water ingress by manufacturing a cradle to suspend the logic higher than before. This sits it well above the condensate tray. A plastic cover then sat over the top of the entire logic and this did help quite a lot to solve this issue. This was called a “Hot Logic Rain Cover Kit”

3rd style

* Has completely waterproof electrical connections as well as box. Works very much like a plug and play style controller. We have very few issues with this style of logic.

Thermal overload

Looks very much like a standard thermostat but is missing the temperature disc and therefore only acts as a thermal overload. If this ever fails please be careful that it hasn’t failed for a reason. E.g. the tank has overheated.

Airoheat sensors

There are 3 airoheat sensors that connect in the hot logic. Very rarely will you have issues with a sensor.

1 Ambient air temperature sensor.

Ambient Air Temperature sensor $55

This is really the only sensor that we can replace as a plumber/electrician

2 Over pressure switch. This is connected to the refrigerator side. You can bypass for testing to confirm it is not an issue with the hot logic but if it has failed we usually recommend replacement of the entire unit if over 5 years

3 Tank temperature sensor. This is fixed to the tank wall and usually only has issues when it has been damaged during the manufacturing process. If this is failed the tank may simply not heat up or do the opposite and overheat. If this happens the entire tank needs to be thrown out and replaced.

Over pressure switch

As suggested earlier in Airoheat sensors you can test to confirm there is not an issue with the hot logic but usually need to get a refrigeration mechanic in to repair if economical.

Pressure temperature relief valve

Due to Dux installing aluminum anodes in the airoheat for all water conditions it tended to cause issues with the pressure temperature relief valve leaking prematurely. As a standard we would only replace that relief valve with a high quality stainless steel seat valve. Sometimes a tank flush and anode replacement would need to be done to. You will see a lot yellow gooey liquid if you do this.


Very few issues with the capacitor on this or any heat pump. Can test using microfarad of the capacitor to work out if it is still go or not. Likely to never have an issue with it though.

Dux Airoheat Heat Pump
Supply and install external Dux Airoheat heat pump in existing location. Old system is taken away free of charge.
Supply and install Price: $3,200.00
STC’s need to be signed to Same Day Hot Water Service as a point of sale discount.

Tempering valve if needed is an additional $165.00
Supply only Price: $3,120.00

Dux Heat Pump old style manual

Dux Airoheat New style owners guide

How the Dux Airoheat work