Anyone had issues with the grippatank hot water system _ cutting out continually
These heaters are primarily designed as engine preheaters and adapted to other requirements.
If your batteries are fully charged then there is another issue.
When the internal heating circuit reaches a preset heat the heater goes into reduced heat mode. If the heat isn't bled off the hot water temperature continues to rise a few more degrees at which time the heater will go into shut down mode. Shut down takes around 180 secs. During this time the hot water circulation pump will continue to circulate hot water around the circuit. If that water temperature suddenly drops then the heater will fire up again taking another 180 seconds.
Now lets say you stop to talk to your customer. The heater will go into reduced heat mode and if you talk for too long will switch off.
You start cleaning again. Initially the water is hot but very quickly will go cold. Back in the van the heater is trying to start and generate more hot water. But you are zapping the heat generated before the internal circuit has had a chance to heat that internal circuit up again. So you end up chasing your proverbial tail.