vovlo AQD40A circulation pump

[solitaire11]

hi all,
since purchasing this boat my calorifier never even gets luke warm, in fact it stays ice cold, and when i open her up to get on the plane the engine temp rises rapidly, and drops just as quick when throttling back. i've checked the stats(fine), and there is'nt a blockage in calorifier as i can blow through both ways, however when i took calorifier pipe off the circulation pump end the water/antifreeze flows out nicely, but when i start the engine it stops flowing altogether?? surely when engine is running the flow should increase dramatically? i am certain it has to be a problem with the circulation pump? next step is to take it off and have a look.. just thought i'd ask to see if anyone has heard of these pumps failing..

cheers in advance rich.

 

[spannerman]

Thats probably the return pipe so will not have any flow when the engine is running, the hot water out to the calorifier usually comes dircetly from the thermostats housing as this is the highest and hottest point in the system.

 

[solitaire11]

thanks for the reply spannerman, the other pipe does indeed go to the thermostat housing and i did wonder, but what pushes it round the calorifier and why is'nt it flowing..lol i know circulation pumps rarely fail.

 

[spannerman]

There should be positive pressure at the thermostat fitting as the circulation pump pushes coolant around the block and up to the cylinder head and it exits via the thermostat housing when the stat opens.
Is your calorifier higher than the engine? Mine is and I have to fill it by taking off one of the hoses and filling the calorifier with funnel then when its full reconnecting it, not ideal but thats the way it was installed when I bought it and it gets the domestic water very hot.

 

[solitaire11]

i would say they are the same level, i totally drained the system from back end of block and filled with hose very slowly from the same drain so as to not get air in, took the calorifier pipe off thermostat housing and filled till it came out of pipe, the system was definately full, then connected it back on, ran for ages and still nothing. my pipe goes in above the thermostats just below the vent pipe fitting??

it just seems odd to me why the pump end is'nt the pushing one?