Water pump - issue airlock ? Motorhome

I do not think you have an airlock more likely an air leak on the suction side of the pump. could be a cracked hose fitting or if you have a filter with a glass sediment bowl that could be cracked. you could try an old trick by closing all taps except the shower then take off the shower head and with the pump running suck as hard as you can on the shower hose end this will help to draw water up from the tank to the pump but will only work if you do not have the leaks mentioned above. It has worked for me many times. goodluck

Thanks very much did not know about the shower trick .. it makes sense . Got one mouthful of water then just air . So yes your right I must have a leak from tank to pump . So I will try pouring more water down the tank suction hose with pump running and tap open , and then check for leaks .. my pump does a a small glass cup on the inlet would that be the filter , it's a but awakward becuse you cannot get to it as its flat on the floor 

thanks for your help with this

regards nick 

notwithstanding any leaks on the input side, as mentioned....

if you have drained the fresh tank and the how water boiler, if you have the pump on, it will be the water boiler that fills first....this will take quite a few minutes, as it will need to fully fill before dispensing much other than air from the hot taps....

similarly, as the pump is dragging fresh water into the hot tank, you might not get much from the cold tap for a while either....

when filling my own hot tank (combi 6e) the pump will stop when its full (if all taps are closed)....i then know its full and can start to ease the air from both sides of the hot/cold system.

i would close the taps, turn on thenpump and ensure that you hear it stop when the hot tank is full.....this will confirm the cold is being pumped into the tank and that the pressure based pump stops when its full....this will put ypur mind at rest that the system is filling properly.

then open the taps slowly, letting any air escape, the pump shpuld come on again and the amount of water increase slightly as the air reduces.

good luck.

I had an intermittent problem similar to this, it turned out to be air being sucked into the plastic pipes near the surge damper .The pipe was cut a little short and was not pushed into the coupling as far as it should have been. It only happened about once in approximatly every 20 nights use and was a real pain. Have a good push and make sure all the plastics pipe ends are fully home.  Good Luck

If you did drain the hot water tank, did you remember to close the drain down valve? Check under the van to ensure water isn't running out as fast as the pump tries to push it into the system. Most of us have done this at least once!

Thanks Your advice was spot on about sucking on the shower hose worked for me when I had no flow and the pump running continuously on my Delaware. I probably created my own problem when I drained the system hence creating a air lock.