You must have a hot tap open Jackie or the air in the tank has nowhere to get out at the top as the cold water tries to come in at the bottom. When water flows freely without spluttering from a hot tap then you will know the tank is full and the air removed. A problem with carver cascade 2's at this time of year is bit of frost damage to the non-return valve which is part of the cold water inlet connection at the bottom right hand corner of the heater. If frost damages this valve it tends to stick and prevent water coming from the hot tap as no water can enter at the bottom to push it out the top,
the only real solution is to replace the connection complete with the valve. In winter always leave the drain bung loose in it's hole so water can always drain away and prevent this happening.
This lot below will give you a good idea how the heater is meant to work.
The Carver Cascade 2 is a 9 litre storage water heater, which when running on gas will heat the water to 65deg c in about 45 minutes. On 240V mains assuming it has this facility, the time can be somewhat longer or shorter depending on the wattage (660w 3amp to 970w 5amp) of the element fitted, you can use both gas and electric together for faster times.
To operate the gas there is a wall switch with three lights, green amber and red. When switched on the green lights, (water tank must be full, i.e. water coming from hot taps), if it stays on after about 8 seconds then the gas has lit and all is well. If the green is joined by the red then you may have a problem, but if the gas bottle has just been changed then air in the pipes will have to be bled through by repeating the above 2 or 3 times. Once lit, and it should light without any pops and bangs, (this would indicate it needs a service), the heater looks after itself and gives constant hot water. Any problems will cause it to shut down safely and show the red light, indicating a fault. Forget the amber light, it’s to show low voltage and won’t light unless the voltage is so low the heater and everything else packed up long since, though you may notice it ‘flash’ as the switch is turned on or off.
The 240v emersion heater if fitted is totally separate, and lies behind a white plastic box on the inboard end of the water tank. It is controlled by a switch, often close by and at floor level, but sometimes as part of a remote control panel. The switch has a red light to show it’s “on”, not that it’s working, this will be determined by the water getting hot. If it does not then it may have “tripped” Two types exist, early circa 1990 are non-re-settable, but are repairable. Later models have a Red button on the end of the plastic box, sometimes behind a flap. Switch off mains, and press to reset.
Other faults concerning the gas side very often come down to the “Burner Module”. This handy little unit contains the burner, gas valve and all the electronics which control it, and is accessible from behind the cover outside of the van. In the event things go wrong it’s a 5 minute job to replace it, either with a new or serviced exchange unit. One other safety device is a wax filled plug, this again is behind the outer cover and shows itself as a 13 mm nut set in the fins above the burner. The wax will melt if things get too hot allowing hot water from the tank to spray over the burner putting the flame out, this will render things safe, but will probably require a new module because it’s control circuitry will be faulty,. A point to note here is that over time the wax degrades or the threads leak, allowing water to seep onto the burner causing it to rust prematurely, eventually this will require replacement of the whole burner module.
That in a nut shell as they say, is all there is to it.
Wednesday, 9 March 2005