Carrier 58TN0B - Adjustments

58TN0B/58TN1B: Installation, Start–Up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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plate. For installations above 2000 Ft. (610 M), multiply the input
on the rating plate by the de-rate multiplier in Table 17 for the
correct input rate.
A93059
Fig. 48 – Orifice Hole
2. Determine the correct orifice and manifold pressure adjustment. All
models in all positions except Low NOx models in downflow and
horizontal positions use Table 19 (22,000 BTUh per burner.) Low
NOx models in downflow or horizontal positions must use Table 20
(21,000 BTUh per burner.) See input listed on rating plate.
a. Obtain average yearly gas heat value (at installed altitude) from
local gas supplier.
b. Obtain average yearly gas specific gravity from local gas
supplier.
c. Find installation altitude in Table 19 or Table 20.
d. Find closest natural gas heat value and specific gravity in
Table 19 or Table 20.
e. Follow heat value and specific gravity lines to point of
intersection to find orifice size and low-and high-heat manifold
pressure settings for proper operation.
f. Check and verify burner orifice size in furnace. NEVER
ASSUME ORIFICE SIZE. ALWAYS CHECK AND VERIFY.
NOTE: If orifice hole appears damaged or it is suspected to have been
redrilled, check orifice hole with a numbered drill bit of correct size.
Never redrill an orifice. A burr-free and squarely aligned orifice hole is
essential for proper flame characteristics.
g. Replace orifice with correct size, if required by Table 19 or
Table 20. Use only factory-supplied orifices. See Example
below.
3. Adjust manifold pressure to obtain low fire input rate, see Fig. 22.
a. Turn gas valve ON/OFF switch to OFF.
b. Remove manifold pressure tap plug from gas valve.
c. Connect a water column manometer or similar device to
manifold pressure tap.
d. Turn gas valve ON/OFF switch to ON.
e. On the 3 digit display, navigate to (Htt) and select (2st) to lock
furnace in low-heat operation see Fig. 29.
f. Manually close blower door switch.
g. Jumper R and W/W1 thermostat connections on control to start
furnace, see Fig. 29.
h. Remove regulator adjustment cap from low heat gas valve
pressure regulator (see Fig. 22) and turn low-heat adjusting
screw (3/16 or smaller flat-tipped screwdriver) counterclockwise
(out) to decrease input rate or clockwise (in) to increase input
rate.
NOTE: DO NOT set low-heat manifold pressure less than 1.4-in. w.c. or
more than 1.7-in. w.c. for natural gas. If manifold pressure is outside this
range, change main burner orifices.
i. Install low-heat regulator adjustment cap.
j. Leave manometer or similar device connected and proceed to
Step 4.
4. Adjust manifold pressure to obtain high fire input rate, see Fig. 22.
a. Jumper R to W/W1 and W2 thermostat connections on furnace
control. This keeps furnace locked in high-heat operation.
b. Remove regulator adjustment cap from high-heat gas valve
pressure regulator, see Fig. 22, and turn high heat adjusting screw
(3/16-in. or smaller flat-tipped screwdriver) counterclockwise
(out) to decrease input rate or clockwise (in) to increase input
rate.
NOTE: DO NOT set high-heat manifold pressure less than 3.2-in. w.c.
or more than 3.8 in. w.c. for natural gas. If manifold pressure is outside
this range, change main burner orifices to obtain manifold pressure in
this range.
c. When correct input is obtained, replace caps that conceal gas
valve regulator adjustment screws. Main burner flame should be
clear blue, almost transparent.
d. Remove jumpers R to W/W1 and R to W2.
5. Verify natural gas input rate by clocking meter.
NOTE: Gas valve regulator adjustment caps must be in place for proper
input to be clocked.
a. Turn off all other gas appliances and pilots served by the meter.
b.
On the 3 digit display, navigate to (Htt) and select (2st). This
keeps furnace locked in low-heat operation. Jumper R to W/W1.
c. Run furnace for 3 minutes in low-heat operation.
CAUTION
!
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in reduced furnace life.
DO NOT redrill orifices. Improper drilling (burrs, out-of-round holes,
etc.) can cause excessive burner noise and misdirection of burner
flames. This can result in flame impingement of heat exchangers,
causing failures, see Fig. 48.
Table 17 – Altitude Derate Multiplier for U.S.A.
ALTITUDE
FT. (M)
PERCENT
OF DERATE
DERATE MULTIPLIER
FACTOR*
0–2000
(0-610)
0 1.00
2001–3000
(610-914)
8–12 0.90
3001–4000
(914-1219)
12–16 0.86
4001–5000
(1219-1524)
16–20 0.82
5001–6000
(1524-1829)
20–24 0.78
6001–7000
(1829-2134)
24–28 0.74
7001–8000
(2134-2438)
28–32 0.70
8001–9000
(2438-2743)
32–36 0.66
9001–10,000
(2743-3048)
36–40 0.62
BURNER
ORIFICE
EXAMPLE: 0–2000 ft. (0-610 M) altitude
For 22,000 BTUh per burner application use Table 19.
Heating value = 1000 BTUh/cu ft.
Specific gravity = 0.62
Therefore: Orifice No. 43*
Manifold pressure: 3.7-in. w.c. for high-heat
1.6-in. w.c. for low-heat
* Furnace is shipped with No. 43 orifices. In this example all main burner orifices are the
correct size and do not need to be changed to obtain proper input rate.