Can a faulty thermostst cause the heater nto explode

I am as of yet unaware of any means in which a pool heater will make a pump explode, but am intrigued, certainly. Actually, I have never heard of any pump "exploding".
I would assume that there must have been some restriction that caused some sort of failure. Can you be more specific about what kind of damage occurred?

Call a qualified service tech immediately.
Gas explosion indicates dirty combustion parts, and gas is not fully igniting when tankless turns on the gas. So gas builds up and then explodes causing serious damage to tankless, and serious risk to homeowner.

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Yes it could be the thermostst. If you have no way to check the actual temperature of the engine and the thermostst hasn't been changed recently then I would go ahead and replace it. If that doesn't help you could have a plugged or restricted heater core or a blend door problem among other things. Good luck.

theirs a restriction in one of the hoses or the water pump is failing

if you are looking for the engine thermostat, it is where the UPPER radiator hose comes out of the engine. There is a neck there. 2 bolts (I think) will take the neck off and the thermostst is there.

Yes it could. If the thermostat is faulty it can cause the dryer to short cycle. If you have a thermometer that you can use to check the heat coming out of the dryer when running with no load it should go off at around 170 degrees F and come back on after dropping 30 to 50 degrees. If it is cycling too soon the thermostat is the most probable problem.

it may be low oil pressure due to a restriction in the engine or if the engine has high mileage and alot of wear and tear will cause low oil pressure one other possibilty is faulty oil pressure switch

sediment in the heater core can cause this . also low coolant power flushing the core can help to restor heater function.BUT THE CORRECT METHOD & tools must be used or outcome will still be no heat

the heater element has probably gone faulty or the thermostst is faulty, they sould come as one replacement.

Try http://www.pelonis.com/parts.htm