For those who have a Webasto heater and the standard timer, one. The Webasto to revert to continuous operation until manually cancelled.

For those who have a Webasto heater and the standard timer, one complaint is that although one can set up to three ON times on the clock, it is not possible to set an OFF time and the timer has to be manually cancelled. I have discovered though that there is one option which is not mentioned in the instructions, towit: At the back of the timer you will find a black wire which loops between two of the 4 connection pins.

Cut this wire in the middle and run the ends to a standard ON-OFF switch (a low current switch is OK). If this switch is closed (ie: ON), then the Webasto will function as per normal. However, if the switch is open (ie: OFF) the Webasto will perform as normal BUT will switch itself OFF automatically after one hour.

Note that if the Webasto is started in normal mode and this switch later switched to open, the Webasto will continue for one more hour and switch itself OFF. This also works the other way round, viz: if you open the switch to obtain one hour's use of the Webasto but change your mind later, closing the switch will cause the Webasto to revert to continuous operation until manually cancelled. I had a conversation with one of Webasto's technical guys to whom I had complained that 3 different instruction sets that came with the unit claimed that it would switch off automatically after 30 minutes, 60 minutes or not at all!! He was the one that let me into the 'secret'. I have modified mine and the mod works perfectly. I have 2 standard rads, 1 bathroom towel rail and a 60 litre calorifier. Whilst one hour is definitely more than sufficient to get the boat toasty warm, it isn't sufficient to heat the calorifier to 'shower heat' if the water is at ambient.

The maths confirms this - it needs about 3 hours starting with cold water. From start-up, in the morning, my unit runs on full power for about 25 minutes (5KW) and then cuts down to half power for the rest of its ON time. If I turn down the rads on their thermostatic valves so more heat goes into the calorifier, the Webasto goes into its 'idle' mode on a 50% basis - ie: 3 minutes ON and 3 minutes idling, because the calorifier alone cannot absorb 2.5KW of heat input from the Webasto's half power mode. I thought this might be an error so plugged my Webasto into a laptop running the Webasto diagnostic software (c/o a friendly local Webasto dealer). The unit was working perfectly as per the technical manual - idling once the water reached 76.5degC and resuming half power once the temperature drops to 71degC. 'Idling' means the water pump keeps operating but the burner is OFF.

If the water temperature should drop to 58degC (eg: switching ON some cold rads) the Webasto will come on to full power until the water temperature reaches 71degC once more when it will switch to half power. I had one problem in the first few days (the new boat is now 2 months old) whereby the Webasto was just not heating the rads nor the calorifier properly. I dismantled the unit and in the water pump found a ball of plastic swarf which, from its colour, clearly came from the header tank.

Some idiot had obviously drilled a hole for a connector and had allowed the swarf to fall into the header tank where it subsequently got sucked into the pump. All's well now though. For those who have a Webasto heater and the standard timer, one complaint is that although one can set up to three ON times on the clock, it is not possible to set an OFF time and the timer has to be manually cancelled. I have discovered though that there is one option which is not mentioned in the instructions, towit: At the back of the timer you will find a black wire which loops between two of the 4 connection pins. Cut this wire in the middle and run the ends to a standard ON-OFF switch (a low current switch is OK).

If this switch is closed (ie: ON), then the Webasto will function as per normal. However, if the switch is open (ie: OFF) the Webasto will perform as normal BUT will switch itself OFF automatically after one hour.