Water Regulating Valve
Water-regulating valves controlled by refrigerant head pressure are recommended to be installed in the supply water line to a condenser. I've seen several installed many years ago that are in the condenser leaving water line.
What are some reasons for the recommended location as being in the supply line and not in the return line?
I'm still learning this trade.
They need to be in the outlet, not the inlet. Otherwise the water will just go down the drain.
Let me clarify that thought.
The water is held in the condenser by the reg valve. When the condensing temp rises, the valve opens up and let's fresh water in, by letting water flow out of the coil. If the valve were to be placed on the inlet, it would open up, and the water would simply flow through the coil and out to the drain. The coil temp would never be regulated.
Most water cooled units I see are always on the inlet side of the condenser. The only one that I can think of that regulates on the outlet side is Hoshi ice machines. I believe the said they use a little less water that way but I could be wrong.
I must agree most I have seen are on the inlet side of the condenser. I have seen them on the outlet but rarely.
If the regulating valve is placed on the supply water side, the out let line has to rise above the condenser, in effect, acting as a trap and allowing the condenser to stay full of water.
One positive point to keeping the regulating valve on the inlet is the water pressure in the condenser will be at atmospheric pressure. If you have a rupture in the wall between the refrigerant/water, as the gas leaks out into the water, little or no water will enter the system. Eventually, all the gas will leak out and both the water side and refrigerant side will be at 0 psi.
In the same scenario, with the regulating valve on the outlet side, when the system loses it's refrigerant charge, the coolant water, under line pressure will be forced into the system.
This is not 100% black and white. It would depend on other factors such as, if the compressor is tripped or cycling on a LP control.
Hoshizaki does install their regulating valves on the outlet of the condenser. And I have seen Hoshi machines squirting water out of the service valves.
I would like the hear what others have to say.
Experience is what you have an hour after you need it.
Methinks reading the IOM is a good idea. In a ton of years Hosi is the only one I have seen on the outlet.
If you really know how it works, you have an execellent chance of fixin' er up!
Tomorrow is promised to no one...
I have seen 1 or 2 inlet valves allow the water to completely drain from the condenser. This was on larger machines though, and I too have seen water coming from Schraeders on large outlet regulated water cooled condensers that blew a tube.
So long as you stop the water from completely draining from the condenser, the inlet regulated valve setup is the way to go, IMHO
Extended dehydration is the key
According to Penn/Johnson Controls, the preferred method is to install the valve on the inlet to the condenser but if the condenser must be fully flooded it may be installed on the outlet side. This is an except from their installation instructions sheet:
It make no difference to the valve operation, and as I see it, if the outlet of the condenser goes to atmospheric pressure, install the valve on the inlet side and simply pipe the outlet so the condenser isn't free-draining. Then, you keep the condenser flooded and at atmospheric pressure during the off-cycle.
Flush water lines to clear any foreign matter that may
interfere with valve operation. Mount valves vertically
on the inlet side of the condenser with spring housing
up. If it is necessary to keep the condenser flooded
with coolant, the valve can be mounted on the outlet
side. When mounting the valve in a position other than
vertical, follow the instructions of the equipment in
which the valve will be installed. Make refrigerant head
pressure connection to bellows. If additional capillary
tubing is required, use 1/4 in. O.D. tubing or larger.
Mounting on the inlet tends to keep water hammer down. But then I'm using tower water so I have pressure on both lines. Still I generally see them on the inlet side, even on ice machines.