HTP Fire Tube Boiler overheating

Redicliff

We have an HTP flash heater MC-100 that is overheating.
I've posted a 1.5 min video of the control panel as the unit cycles.
https://www.dropbox.com/s/cuakr4pa010f2xq/HTP Boiler Overheating.mov?dl=0

Not finding corresponding troubleshooting recommendations in the manual. Of course, if it's there, it probably reads "call a certified tech". But, we're sheltered in place a long ways from a tech.

Comments and recommendations appreciated

kcopp

From the description you are not getting flow. Is something shut off, circulator broken or debris plugging the piping?

EBEBRATT-Ed

Or no or low water pressure in the system.

fenkel

Check your pumps..water isnot moving thru HX..

GroundUp

Not enough flow, can hear it boiling in the HX. How's it piped?

hot_rod

they can be tricky to purge the boiler on fire tube design. i have had to hold the relief valve open if you do not have enough purge flow or pressure.

fenkel

Whats the boiler pressure? Should be a guage under the boiler?
Upload more pictures, sometimes we can see issues..

Rich_49

If this in fact an MC series boiler , it is not a firetube . MC Series was a water tube boiler

fenkel

How old is boiler?
Could HX be plugged?