Filled up the water tank and with new filter run through taps.
Turned on mains switch to carver water heater and got one green and one red light but only cold water.
Waited 20 min's but still cold, any suggestions.
I am not using the gas as this is turned off only mains electric.
Hell Reg and Pat
You don't tell us which model of heater you have;
The Cascade was introduced in 1979 and consisted of a mushroom shaped copper tank covered with a red gals fibre filled insulation jacket. It was mounted through the floor of the caravan. This model was gas only and not available with a mains heater. It had one control panel either a square white panel with separate red yellow and green LEDs, or a rectangular beige box with a single green LED.
The Cascade 2 was introduced in 1984 as a gas only heater, it consist of a aluminim cylinder mounted horizontally through the sode wall of the caravan. later versions had a mains element also and were designated Cascade 2 GE and the Cascade rapide, The gas control panel was a beige rectangular box with 3 LEDs behind a common lense. It later changed to beige square panel with 3 Leds and two grey push buttons. The mains element always had a separate control panel. the caravan manufacture had to supply and fit it, usually to the kick board of the bedding locker. It will be a mains switch with a fuse holder, and depending on the caravan manufacturers whim, it may or may not have neon indicator.
It sound as though you have been confused by the switches. The switch with the red yellow and green lights only controls the gas side of the heater. The fact that you have green light followed by a red light indicates that the gas burner has tried to light, but because you have the gas turned off, it failed to light so it has gone to lock out.
You need to find the associated mains switch for the heater. To locate the switch, look at the inboard end of the water heater tank. The GE model will have a with plastic curved top box on the end of the tank. Coming away from it will be a mains cable. Follow it through and it will go to a fused spur switch, usually mounted on the kick board of the bed.
I strongly suggest you obtain a copy of the owners had book for the appliance, Check Gary's web side at http://www.arcsystems.biz. Where he has copies of most of the Carver manuals.