JOHNSON CONTROLS
36
FORM 150.27-NM1
ISSUE DATE: 09/30/2015
SECTION 4 – INSTALLATION
WATER TREATMENT
The unit performance given in the Design Guide is
based on a fouling factor of 0.00025 ft
2
/hr °F/BTU
(0.44m
2
ºC/kW). Dirt, scale, grease and certain types
of water treatment will adversely affect the heat ex-
changer surfaces and therefore unit performance. For-
eign matter in the water system(s) can increase the heat
exchanger pressure drop, reducing the flow rate and
causing potential damage to the heat exchanger tubes.
Aerated, brackish or salt water is not recommended for
use in the water system(s). Johnson Controls recom-
mends that a water treatment specialist is consulted to
determine that the proposed water composition will not
affect the evaporator materials of carbon steel and cop-
per. The pH value of the water flowing through the heat
exchangers must be kept between 7 and 8.5.
Glycol Solutions
For unit operation with chilled liquid temperatures leaving
the cooler at below 40°F (4.4°C), glycol solutions should
be used to help prevent freezing.
, gives recommended solu-
tion strength with water, as a percentage by weight, for
the most common types of glycol. It is important to check
glycol concentration regularly to ensure adequate concen-
tration and avoid possible freeze-up in the cooler.
When using glycol solutions, pressure
drops are higher than with water. Special
care must be taken not to exceed the maxi-
mum pressure drop allowed.
OPTION FLANGES
One of two types of flanges may be fitted depending
on the customer or local Pressure Vessel Code require-
ments. These are Victaulic adapter flanges or weld flang-
es. Victaulic adapter flanges are supplied loose for field
installation and weld flanges are factory fitted. Flange
dimensions are to ISO 7005 - NP10 (BS 4504 - NP10).
LD06602
FIGURE 8 -
VICTAULIC - ADAPTER FLANGES
REFRIGERANT RELIEF VALVE PIPING
The cooler and low side piping is protected against in-
ternal refrigerant overpressure by a 400 PSIG refriger-
ant relief valve
.
It is recommended that each valve should be piped to
the exterior of the building so that when the valve is
activated the release of high pressure gas and liquid
cannot be a danger or cause injury.
The size of any pipework attached to a relief valve
must be of sufficient diameter so as not to cause re-
sistance to the operation of the valve.
For piping size
requirements and specifications, refer to ASHRE-15
(latest edition).
If relief pipework is common to more than one valve its
cross sectional area must be at least the total required
by each valve. Valve types should not be mixed on a
common pipe. Precautions should be taken to ensure
that the exit of relief valves/vent pipe remain clear of
obstructions at all times.
Unless otherwise specified by local regulations, the in-
ternal diameter depends on the length of pipe required
and is given by the following formula:
D
5
= 1.447 x L
Where:
D = minimum pipe internal diameter (cm)
L = length of pipe (m)
CONDENSER RELIEF VALVE
A high side pressure relief valve will normally be re-
quired. The pressure rating of the valve will be deter-
mined by the lowest pressure rated component in the
high side, and local code. This valve will need to be
installed in the high side piping.
The YCRL is shipped with a high pressure cutout that
opens at 585 plus or minus 10 PSIG. This may need to
be field changed to a lower rating depending upon the
lowest rated component on the high side in the remote
piping / condenser.
