Why do we only use DP transmitter in boiler furnace draft

What is the need for DP transmitter in boiler

Boilers have both forced draft and induced draft.

Forced draft flow FD can be DP type /flow nozzle for inlet burner air.

Induced Draft, ID uses DP type for Flow towards the stack.

Low-pressure variations as it is atmospheric, DP type is most sensitive, and easy maintenance is possible.

Most manufacturers do not have a very low pressure, ‘draft range’ gauge pressure transmitter because of low market demand for such. In fact, I do not know of a manufacturer of industrial ‘draft range’ gauge pressure transmitters.

So the when a low pressure ‘draft range’ pressure transmitter is required, the only model available for ‘draft range’ is a ‘draft range’ DP differential transmitter.

With a DP transmitter the high side port is the same as gauge pressure sensing port. The low side port on a DP is left open to atmosphere, although I always install a mesh or sintered filter in the low side port to prevent insects from building homes in the low side sensing area.