Slight error, being a Truma heating system I don't have any manuals on my website!
The Truma fan speed control has three settings, off is in the middle and left or right gives, manual fan speed, or, 'A'utomatic fan speed.
Below is my general advice on how best to use the electric heating, at least it should give you a good start:
The Ultraheat's wattage settings are there so you can make use of low amperage hookups, 500W for 6A, 1000W for 10A and 2000W for 16A hookups, their not there to adjust the temperature of the van.
The Ultraheat is thermostatically controlled, therefore the wattage used will simply mean the fire is heating for shorter or longer periods. Where the problems arise then is if the temperature control is not working correctly, this is often due to the heat from the elements directly affecting the sensor itself, it's within the control switch. This means the heat brings the temperature sensor up to that set on the dial and the elements switch off, you and the vans are still cold but the sensors toasty and takes forever to cool before switching the fire back on!!
Due to this and particularly overnight, it's become something of an urban myth to set it at 500w or 1000w, this or that number on the dial and fan speed setting. In truth what's happening is the available heat is not capable of reaching the set temperature so never switches off, it's a useful work around but not how it should work.
The real solution is to fit a 'remote' temperature sensor and attach it to the gas fires sensor, if a remote is already fitted, it to will usually react better if moved to this location.
Setting the fan on manual speed means the fan runs at this speed regardless of the amount of heat being produced, I would suggest manual fan is only for use without heat for cooling in summer, if infact it has a use?!
Setting the fan to 'A'utomatic allows the heat produced to control the fan speed 'up' to the speed set on the dial, you can then, keep this set maximum low and therefore quiet over night perhaps
Automatic means the fan will run slowly initially and speed up as the air passing through gets warmer, doing it this way allows heat and fan to be switched on together and doing away with waiting xx minutes as often suggested.
I would suggest as a start and during the day, the wattage selected is as high as the hook up allows and then fan speed set to maximum on Automatic.
This provides the maximum heat if required and the fans speed will respond to change in temperature, ie, fast when heat cycle is on and slow when heat is off.
After that you can fine tune to suit your own needs
Other heating problems concern the control board, the elements are switched on and off by relays and the contacts burn out, particularly the two 1kw relays. If this happens you may think you have it set to 2kw but only one element is working, finally perhaps leaving you with just 500w working when both 2kw and1kw settings no longer work.
(Note, relays will still be heard to 'click' but unless you have heat, their not working)
The 12v for control also comes from this board and the transformer sometimes packs up, apart from no heat, you will lose the green light in the switch if this happens
Lastly and also if no heat is forth coming, there are two safety thermostats, one at least of these has a habit of self destruction which stops all heating on electric! If the lower 125C thermostat trips, it automatically resets when it cools. However, the 175C limit stat is a 'self hold' and cannot reset once tripped until the mains supply to the heater is switched off, once mains supply is off, it will then cool and reset automatically.
The control switch itself seems generally reliable but the odd one does fail.
The numbers on the dial represent roughly 4degs and 9 is 32degs or thereabouts, this in theory makes 6 or 7 'normal' but it's what feels comfortable that matters not the number.
Another problem not caused by the heater itself is long runs of un-insulated blown air pipe running outside under the floor, insulating this will improve matters considerable.
Everything installed and working as it should, there is no good reason why the electric heating should not work very well and keep an even temperature to suit your needs.
However, it must be remembered the van needs to be warmed through thoroughly, not just the air, before the heating is turned down. While the vans cold it will constantly drag heat from the air and this in turn needs constant topping up or the van will always feel 'draughty'. It's most useful then while particularly cold to use gas as well for the first couple of hours, also, if the heating is off during the day to turn it back on at the first sign of a chill.
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