Diesel Heaters

You most likely have a Planar, I have one as do several of my friends & they all perform faultlessly. When it was installed did you mount the pump at the designated angle?

Yes Shaker, it definitely isn’t Planner. All the installation info has PLANAR printed on it. DIESEL. is named after Rudolph of the same name.
Leave the a in there and drop the I, it will become desal, no salt.

Johno59

You still haven’t given an account of what you have checked to give much of an idea as to what, has and hasn’t, been done. Makes diagnosis of problems via the light beam fairly difficult. Why don’t you find someone who has used one and knows a little about them to sort your problems.
Recently you said it ran for 2 hours, no worries.

What is the problem now????

As Shaker said, did you mount the pump as directed?
Does your battery voltage stay sufficiently high enough for ALL the expected run time?? You haven’t answered that question yet.
We try to help you, but it seems you don’t wish to help yourself.

I have purchased 3 of the EBay diesel heaters recently and all are good - a 3kW for a Tvan and two 5Kw for mates caravans. I also have an Eberspacher D2 2.2Kw in our caravan. The EBay ones cost between $200 and $300 and the Eberspacher is a smaller unit and costs $2000. Components look very similar
As stated above, you must have good battery power and wiring to it as the glow plug draws up to 10Amps when warming up, and the fuel pump must be directed upwards 30 degrees or so.

Johno
I hope you didn't have the heater inlet drawing air from a sealed underbed cavity. That would starve flow. Ins and outs have to be the same.

Is it possible the air circuit is "short circuiting"? That is, heated air is getting back into the cold air intake too soon.

If your hot air outlet is directed at 90 degrees to a nearby wall and the return air inlet is not too far away from the hot air outlet, then you could get an " air short circuit". This can cause an overheat situation.

Cheers