I am not familiar with the Coleman A/C, but it is possible that it won't heat when the temperature gets down a bit. It is all to do with the coils in the unit. The A/C unit extracts heat from one side and dumps it into the other side of the unit. If you are cooling the van, it takes heat from inside and dumps it outside. If you are heating , the reverse applies. As you take heat from the outside, the temperature of the coils drops, and ice forms, blocking the airflow and stuffing up the performance of the unit. If you are in a dry area, the unit will operate down to much lower levels than if it is moist outside.
It is all to do with the design of the outer coils. You can buy a reverse cycle A/C window rattler unit and it will shut down at around 4 Deg C. The unit then pumps gas back through the outer coils until they de-ice and it starts up again. In a window rattler (and also a mobile unit like your Coleman), the coils are compact and don't have much surface area. Larger split system domestic A/C units have a different design for the outer unit - they normally only have 2 rows of coils and it is harder for the ice to form on the outer coils. We have a split system A/C unit in our house which we use for heating and cooling. It operates down to -10 Deg C and because we are in a relatively dry area, it rarely stops. The worst time for us is when it is around 2 to 4 Deg C and it is foggy. The unit then starts/stops until the fog clears.
We have a split system A/C in our caravan. It doesn't even try to operate in reverse cycle - it simply has a heater element built in and it works very well when we use it as a heater. I am surprised that the Coleman doesn't have a similar system because when it is cold outside is when you need it most.
Out last caravan was like that, we went to Pemberton WA one winter,the temp got to 2 deg no heat lucky had a little fan heater saved the day so no it not faulty imho.The Ibis we have now is ok in winter so I think it is a design fault .
Thanks Guys for the replies. We were in Toowoomba 3 degrees on the truck thermometer so probably lower on the MH roof and we had to resort to the fan heater.
first thing is to check the outdoor operating temperature design conditions, these should be shown in the users manual, this will show what outdoor cooling and heating temperature conditions the unit is design to operate under.
Check if the unit is a reverse cycle or element heat model.
Contact Coleman and request the expanded temperature and capacity data information, this will show you what cooling and heating capacity the unit has at different outdoor temperatures, this information will answer most of your questions.
Be aware that caravan air conditioners are not tested to the Australian Standards for cooling and heating capacity (MEPS) which ALL other air conditioners MUST comply with.
Coleman Mach-8 is a full reverse cycle air conditioner.....7 day programming ... Reverse Cycle (Heating is ineffective when outside temperature is below 2C
