# Is it possible to create circulation of water in bypass pipe without water pump?

There is a pipe of 32mm in diameter. Water flows from left to right. There are two branches in that pipe. To one of them connected input of water heat exchanger, to another - output of water heat exchanger. Pipe inside of heat exchanger has size of 3/4 inch. That means there is reduction of diameter. Is it possible to create circulation without water pump in that heat exchanger by playing with pipe size, angles of branches, etc.?

Update:

I need water to get into heat exchanger, so that it could boil water inside.

• This looks like it's about engineering. – user191954 Sep 4 '18 at 12:59
• Are both places where it branches off at the same height? – JMac Sep 4 '18 at 14:23
• The answer is probably "no", but I can't tell from your diagram. Show more detail, and show the case with and without the circulation pump. – David White Sep 4 '18 at 17:55
• And what if... to use danfoss balancing valve (like Leno™ MSV-S for instance). I install it on 32mm pipe so that part of water could follow heater and another part could move along 32mm pipe? – John Smith Sep 6 '18 at 15:05

The section of the $32$mm pipe running in parallel with the heat exchanger will limit this pressure drop. The smaller the diameter of this section, the greater the flow rate through the heat exchanger will be.