Gas Heat Models - York eco2 050 Installation Operation & Maintenance

Example:
Suction Temp =
Minus Suction Press of
65 PSIG converted to
the Dew Point Temp –
Superheat =
When adjusting the expansion valve, the adjusting screw
should be turned not more than one turn at a time, al-
low ing suf fi cient time (ap prox i mate ly 15 min utes)
be tween ad just ments for the system and the ther mal
ex pan sion valve to re spond and stabilize.
The superheat setting should be adjusted to 15°F at
design conditions.
Subcooling (R-22)
The subcooling temperature of each system can be cal-
cu lat ed by recording the temperature of the liquid line
at the outlet of the condenser and sub tract ing it from
the liquid line saturation tem per a ture at the liquid stop
valve (liquid line saturation temp. is con vert ed from a
tem per a ture/pres sure chart) (See Table 5).
Example:
Liquid line pressure =
202 PSIG converted to
Minus liquid line temp.
Subcooling =
The subcooling should be adjusted to 15°F at de sign
conditions.
After the subcooling is veriÞ ed, the suction su per heat
should be checked. The superheat should be checked
only af ter steady state operation of the unit has been
established, and the unit is run ning in a fully load ed
condition.
Superheat (R-22)
The su per heat is cal cu lat ed as the dif fer ence be tween the
ac tu al tem per a ture of the re turned re frig er ant gas in the
suc tion line en ter ing the com pres sor and the tem per a ture
cor re spond ing to the suction pres sure as shown in a
stan dard pres sure/tem per a ture chart in Fig. 5.
YORK INTERNATIONAL
56°F
43°F
13°F
102°F
- 87°F
15°F
Example:
Suction Temp =
Minus Suction Press
60 PSIG converted to Temp
Superheat =
When adjusting the expansion valve, the adjusting screw
should be turned not more than one turn at a time, al-
low ing suf fi cient time (ap prox i mate ly 15 min utes)
be tween ad just ments for the system and the thermal
ex pan sion valve to re spond and stabilize.
Assure that su per heat is set at 15°F.
Leak Checking
Leak check compressors, Þ ttings and piping to assure
no leaks. Verify the evaporator distributor tubes do not
have bare copper touching each other or are against a
sheet metal edge. If you are leak checking a unit charged
with R-407C make sure the leak test device is capable
of sensing refrigerant R-407C.
If the unit is functioning satisfactorily dur ing the
ini tial op er at ing period, no safeties trip and the unit
controls are functioning prop er ly, the roof top unit is
ready to be placed into operation.

GAS HEAT MODELS

Pre-Start Checks:
• Startup of gas heat includes veriÞ cation of in-
com ing gas line pressure and leak checks in the
Þ eld in stalled gas line, are the responsibility of the
in stall ing contractor, but should be veriÞ ed prior
to unit start-up. Correct values are located later in
this section.
• Verify wiring inside the burner compartment to
in sure the wiring/terminals are tight and securely
con nect ed to the components, such as the ig ni tion
con trol, ß ame sensor, gas valve, rollout switch es
and igniter.
• Check that the transformer is wired for the correct
voltage. The transformer has 2 taps, one for 208
volts and one for 240 volts. Check that the wire ter-
minal is on the correct terminal on the transformer
(on 208 volt units, the tap should be on the 208 term
of the trans; for all other voltages, it should be on
the 240 volt terminal).
FORM 100.50-NOM1 (604)
46°F
- 34°F
12°F
3
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