HydroFire Deluxe EB fireplace

I have purchased a HydroFire Deluxe EB fireplace to warm the house and heat the water in the geyser. It works really well, but occasionally falls apart and blows up, overheats, stops working, leaks and glows red hot! As this happens unpredictably, it is impossible to leave the fireplace alone. I hope this forum may be able to assist with a few suggestions, as the seller (Marksman), Installer (Hugo) and supplier (Hydrofire) are not as responsive as one could hope?

The pump impellor melted as the water was connected to the water drain / exit. Hydrofire have supp**** another plastic impellor as per the attached image. How does one change an impellor?

Would it not be better to put in a metal impellor? If the temperature is going to 150 degrees? and the current impellor melts as 110 degrees?

The expansion vessel blew up, exploded, breaking a solar panel and a roof. Hydrofire have supp**** another, much smaller expansion vessel. What should the size of the expansion vessel be?

The Geyer pump is running continually, there has to be a way to turn the pump on / off as the water gets hot / cold. Would anyone know how to do this?

THE Geyer pump to have the option to turn on manually / manual electric switch - HOW WOULD ONE DO THAT?

The fireplace suddenly gets very hot, the flue glows red, the black pitch runs down THE FLUE. Why this happens is not clear. This needs to be resolved - any suggestions?

How important is it for the Additional components like pump, valves, etc., have to be placed in a visible and easy for access places? Currently unable to access / view any of these.

For those interested, this is the setup: https://youtu.be/XcxuervO1WI

Any and all feedback and support would be appreciated. I would love to talk to someone who has one of these HydroFire Deluxe EB fireplace?

Thank you

Barry T Fryer Dudley ***