Flow Switch

Dear Friends,

Flow switch should be installed either on the " IN " line of Condenser or Evaporator OR on the " OUT " line.I have heard that it should be installed only at the " OUT " line of condenser or evaporator. What are your views and the reasons supporting your answer.

I hope all you will share your views and thanks for your cooperation.

Kind Regards,
Sumit

A flow switch in therory could be installed in either the in or the out, it is only measuring flow. A water control valve should be installed in the out only so that you can be sure you will always have a full water column at start up.

On most of the units I've seen the flow switch is on the outlet as emmet said it makes no difference as long as the flow switch is installed in the right direction

Thanks Emmett and James for your reply.

Lets assume that if we install it at the outlet of Condenser.But due to choking of some tubes in a shell-tube condenser, the flow of water is less than the normal value.Then chiller will start or it will show any warning ?

You can install it on the inlet or outlet, its exactly the same.

If there is no flow or a blockage in either condenser or evaporator, the result is, flow switch tripped..

We always favour on the outlet.
You tend to get a faster response to a blocked Shell and tube on the outlet.
Besides which say the Shell and tube develops a leak.
If fitted to the inlet the flow switch would remain made, whereas on the outlet it would fail.
The flow switch is there to co confirm sufficient flow through the "Heat exchanger". Therefore you can only truly guarantee that if it is fitted to the outlet side.

Generally you can get away with either side, but on the outlet covers more failure scenario's.
Grizzly

Quote:

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Originally Posted by Grizzly

We always favour on the outlet.
You tend to get a faster response to a blocked Shell and tube on the outlet.
Besides which say the Shell and tube develops a leak.
If fitted to the inlet the flow switch would remain made, whereas on the outlet it would fail.
The flow switch is there to co confirm sufficient flow through the "Heat exchanger". Therefore you can only truly guarantee that if it is fitted to the outlet side.

Generally you can get away with either side, but on the outlet covers more failure scenario's.
Grizzly

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I disagree my friend, flow switch is a dumb mechanism that senses flow.
Any drop of water that goes into the condenser\evaporator, comes out.
If it is blocked from any reason, no flow out and no flow in.
In case of a large leak, liquid will flow in but not out!
I always fit them on the inlet, but the outlet is just as good.

I believe that it all started because the flow is more accessible on the outlet and the thinking that a shell and tube evaporator can freeze and water will stop flowing out. In that case they will stop flowing in as well.

hopefully the frost protection stat is fitted by the outlet to prevent freeze up,and on ur condenser circuit uve got ur hp switch and blow offs

Installing flow switch on the inlet have few disadvantages like :

1. If the inlet valve is not working 100 % and due to which there is " always " some flow of water through it towards the evaporator or condenser.Then flow switch will allow the processor to start the chiller, even when the inlet valve is closed.

2. Secondly , installing the flow switch at outlet helps in determining the blockage of tubes inside the evaporator or condenser.

Outlet makes more sense, if the paddle snaps off with it fitted in the inlet will end up within the heat exchanger, someone may leave it in there and eventually it will rub through and cause a leak. At least on the outlet it will get caught elsewhere.

You can install it on the inlet or outlet, its exactly the same. If there is no flow or a blockage in either condenser or evaporator, the result is, flow switch tripped.
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Thanks friends for your reply