Oil Cooler exchanger.

[rsauk]

what is the consequences of not having 'balance' holes
provided in division plates, in channel ends.

the tube side service is cooling water.

 

[aybee]

you can get a differential in pressure across the division plate which can bend the plate and crack the welds holding it to the head which can propagate into the head. the small hole allows a balance of the pressure

 

[DLANDISSR]

rasuk and aybee:

You must have a pressure differential across the heat exchanger from division to division other wise there will be no flow. If you put a hole the divider plate large enough to equalize the pressure you will bypass part of the heat exchanger with obviouis consequenses.

Am I way off base here or what??

The hole you refer to may be a hole to facilitate draining the fluid. Without a hole some fluid may be trapped and could not be drained. Vent holes are sometimes needed to vent air from the divisions as the heat exchanger fills with fluid.