EasyManua.ls Logo

Lennox LDT DUAL FUEL Series - Gas System Adjustments and Checks; Manifold Pressure Adjustment; Flame Sensing and Cooling Checks

Lennox LDT DUAL FUEL Series
50 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Loading...
Page 32
4-Check and Adjust Manifold Pressure
After line pressure has been checked and adjusted, check
manifold pressure. Move test gauge to the outlet pressure
tap located on unit gas valve GV1. See FIGURE 17 for
location of pressure tap on the gas valve.
The manifold pressure is factory set and should not re-
quire adjustment. If manifold pressure is incorrect and no
other source of improper manifold pressure can be found,
the valve must be replaced. See FIGURE 17 for location
ξ™’ξ™‰ξ˜ƒξ™Šξ™„ξ™–ξ˜ƒξ™™ξ™„ξ™ξ™™ξ™ˆξ˜ƒξ˜‹ξ™ξ™„ξ™‘ξ™Œξ™‰ξ™’ξ™ξ™‡ξ˜ƒξ™“ξ™•ξ™ˆξ™–ξ™–ξ™˜ξ™•ξ™ˆξ˜Œξ˜ƒξ™„ξ™‡ξ™ξ™˜ξ™–ξ™—ξ™ξ™ˆξ™‘ξ™—ξ˜ƒξ™–ξ™†ξ™•ξ™ˆξ™šξ˜‘
All gas valves are factory regulated. The gas valve should
ξ™†ξ™’ξ™ξ™“ξ™ξ™ˆξ™—ξ™ˆξ™ξ™œξ˜ƒξ™„ξ™‘ξ™‡ξ˜ƒξ™Œξ™ξ™ξ™ˆξ™‡ξ™Œξ™„ξ™—ξ™ˆξ™ξ™œξ˜ƒξ™†ξ™œξ™†ξ™ξ™ˆξ˜ƒξ™’σ°€¨ξ˜ƒξ™Œξ™‘ξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™ˆξ™™ξ™ˆξ™‘ξ™—ξ˜ƒξ™’ξ™‰ξ˜ƒξ™Šξ™„ξ™–ξ˜ƒ
ξ™’ξ™•ξ˜ƒξ™“ξ™’ξ™šξ™ˆξ™•ξ˜ƒξ™‰ξ™„ξ™Œξ™ξ™˜ξ™•ξ™ˆξ˜‘ξ˜ƒξ˜·ξ™‹ξ™ˆξ˜ƒξ™ξ™„ξ™‘ξ™˜ξ™„ξ™ξ˜ƒξ™–ξ™‹ξ™˜ξ™—ξ˜ξ™’σ°€¨ξ˜ƒξ™Žξ™‘ξ™’ξ™…ξ˜ƒξ™†ξ™„ξ™‘ξ˜ƒξ™…ξ™ˆξ˜ƒξ™˜ξ™–ξ™ˆξ™‡ξ˜ƒξ™—ξ™’ξ˜ƒ
ξ™Œξ™ξ™ξ™ˆξ™‡ξ™Œξ™„ξ™—ξ™ˆξ™ξ™œξ˜ƒξ™–ξ™‹ξ™˜ξ™—ξ˜ƒξ™’σ°€¨ξ˜ƒξ™Šξ™„ξ™–ξ˜ƒξ™–ξ™˜ξ™“ξ™“ξ™ξ™œξ˜‘
CAUTION
ξ˜©ξ™’ξ™•ξ˜ƒ ξ™–ξ™„ξ™‰ξ™ˆξ™—ξ™œξ˜ξ˜ƒ ξ™†ξ™’ξ™‘ξ™‘ξ™ˆξ™†ξ™—ξ˜ƒ ξ™„ξ˜ƒ ξ™–ξ™‹ξ™˜ξ™—ξ˜ξ™’σ°€¨ξ˜ƒ ξ™™ξ™„ξ™ξ™™ξ™ˆξ˜ƒ ξ™…ξ™ˆξ™—ξ™šξ™ˆξ™ˆξ™‘ξ˜ƒ ξ™—ξ™‹ξ™ˆξ˜ƒ
ξ™ξ™„ξ™‘ξ™’ξ™ξ™ˆξ™—ξ™ˆξ™•ξ˜ƒξ™„ξ™‘ξ™‡ξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™Šξ™„ξ™–ξ˜ƒξ™—ξ™„ξ™“ξ˜ƒξ™—ξ™’ξ˜ƒξ™“ξ™ˆξ™•ξ™ξ™Œξ™—ξ˜ƒξ™–ξ™‹ξ™˜ξ™—ξ˜ƒξ™’σ°€¨ξ˜ƒξ™’ξ™‰ξ˜ƒξ™Šξ™„ξ™–ξ˜ƒ
pressure to the manometer.
Manifold Adjustment Procedure
1 - Connect test gauge to the outlet pressure tap on the
ξ™Šξ™„ξ™–ξ˜ƒξ™™ξ™„ξ™ξ™™ξ™ˆξ˜‘ξ˜ƒξ˜Άξ™—ξ™„ξ™•ξ™—ξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™˜ξ™‘ξ™Œξ™—ξ˜ƒξ˜‹ξ™†ξ™„ξ™ξ™ξ˜ƒξ™‰ξ™’ξ™•ξ˜ƒξ™–ξ™ˆξ™†ξ™’ξ™‘ξ™‡ξ˜ƒξ™–ξ™—ξ™„ξ™Šξ™ˆξ˜ƒξ™‹ξ™ˆξ™„ξ™—ξ˜Œξ˜ƒ
ξ™„ξ™‘ξ™‡ξ˜ƒξ™„ξ™ξ™ξ™’ξ™šξ˜ƒξšΏξ™™ξ™ˆξ˜ƒξ™ξ™Œξ™‘ξ™˜ξ™—ξ™ˆξ™–ξ˜ƒξ™‰ξ™’ξ™•ξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™˜ξ™‘ξ™Œξ™—ξ˜ƒξ™—ξ™’ξ˜ƒξ™•ξ™ˆξ™„ξ™†ξ™‹ξ˜ƒξ™–ξ™—ξ™ˆξ™„ξ™‡ξ™œξ˜ƒ
state.
2 - While waiting for the unit to stabilize, notice the
ξ›€ξ™„ξ™ξ™ˆξ˜‘ξ˜ƒξ˜·ξ™‹ξ™ˆξ˜ƒξ›€ξ™„ξ™ξ™ˆξ˜ƒξ™–ξ™‹ξ™’ξ™˜ξ™ξ™‡ξ˜ƒξ™…ξ™ˆξ˜ƒξ™–ξ™—ξ™„ξ™…ξ™ξ™ˆξ˜ƒξ™šξ™Œξ™—ξ™‹ξ™’ξ™˜ξ™—ξ˜ƒξ›€ξ™„ξ™–ξ™‹ξ™…ξ™„ξ™†ξ™Žξ˜ƒ
and should not lift from the burner heads. Natural
gas should burn basically blue with some clear
streaks. L.P. gas should burn mostly blue with some
clear yellow streaks.
3 - ξ˜ƒξ˜€ξ™‰ξ™—ξ™ˆξ™•ξ˜ƒξ™„ξ™ξ™ξ™’ξ™šξ™Œξ™‘ξ™Šξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™˜ξ™‘ξ™Œξ™—ξ˜ƒξ™—ξ™’ξ˜ƒξ™–ξ™—ξ™„ξ™…ξ™Œξ™ξ™Œξ™ξ™ˆξ˜ƒξ™‰ξ™’ξ™•ξ˜ƒξšΏξ™™ξ™ˆξ˜ƒξ™ξ™Œξ™‘ξ™˜ξ™—ξ™ˆξ™–ξ˜ξ˜ƒ
record the manifold pressure and compare to the
values given in table 7.
CAUTION
Disconnect heating demand as soon as an accurate
reading has been obtained.
5-Proper Gas Flow
ξ˜©ξ™˜ξ™•ξ™‘ξ™„ξ™†ξ™ˆξ˜ƒξ™–ξ™‹ξ™’ξ™˜ξ™ξ™‡ξ˜ƒξ™’ξ™“ξ™ˆξ™•ξ™„ξ™—ξ™ˆξ˜ƒξ™„ξ™—ξ˜ƒξ™ξ™ˆξ™„ξ™–ξ™—ξ˜ƒξ˜˜ξ˜ƒξ™ξ™Œξ™‘ξ™˜ξ™—ξ™ˆξ™–ξ˜ƒξ™…ξ™ˆξ™‰ξ™’ξ™•ξ™ˆξ˜ƒξ™†ξ™‹ξ™ˆξ™†ξ™Ž-
ξ™Œξ™‘ξ™Šξ˜ƒ ξ™Šξ™„ξ™–ξ˜ƒ ξ›€ξ™’ξ™šξ˜‘ξ˜ƒ ξ˜§ξ™ˆξ™—ξ™ˆξ™•ξ™ξ™Œξ™‘ξ™ˆξ˜ƒ ξ™—ξ™Œξ™ξ™ˆξ˜ƒ ξ™Œξ™‘ξ˜ƒ ξ™–ξ™ˆξ™†ξ™’ξ™‘ξ™‡ξ™–ξ˜ƒ ξ™‰ξ™’ξ™•ξ˜ƒ ξ™—ξ™šξ™’ξ˜ƒ ξ™•ξ™ˆξ™™ξ™’ξ™ξ™˜-
tions of gas through the meter. (Two revolutions assures
ξ™„ξ˜ƒξ™ξ™’ξ™•ξ™ˆξ˜ƒξ™„ξ™†ξ™†ξ™˜ξ™•ξ™„ξ™—ξ™ˆξ˜ƒξ™—ξ™Œξ™ξ™ˆξ˜‘ξ˜Œξ˜ƒξ˜§ξ™Œξ™™ξ™Œξ™‡ξ™ˆξ˜ƒξ™…ξ™œξ˜ƒξ™—ξ™šξ™’ξ˜ƒξ™„ξ™‘ξ™‡ξ˜ƒξ™†ξ™’ξ™ξ™“ξ™„ξ™•ξ™ˆξ˜ƒξ™—ξ™’ξ˜ƒξ™—ξ™Œξ™ξ™ˆξ˜ƒ
in TABLE 11. Seconds in TABLE 11 are based on a 1 cu.ft.
ξ™‡ξ™Œξ™„ξ™ξ˜ƒξ™„ξ™‘ξ™‡ξ˜ƒξ™Šξ™„ξ™–ξ˜ƒξ™™ξ™„ξ™ξ™˜ξ™ˆξ˜ƒξ™’ξ™‰ξ˜ƒξ˜”ξ˜“ξ˜“ξ˜“ξ˜ƒξ™…ξ™—ξ™˜ξšΆξ™–ξ˜ƒξ™‰ξ™’ξ™•ξ˜ƒξ™‘ξ™„ξ™—ξ™˜ξ™•ξ™„ξ™ξ˜ƒξ™„ξ™‘ξ™‡ξ˜ƒξ˜•ξ˜˜ξ˜“ξ˜“ξ˜ƒξ™…ξ™—ξ™˜ξšΆξ™–ξ˜ƒ
for LP. Adjust manifold pressure on gas valve to match
time needed.
NOTE -ξ˜ƒξ˜·ξ™’ξ˜ƒξ™’ξ™…ξ™—ξ™„ξ™Œξ™‘ξ˜ƒξ™„ξ™†ξ™†ξ™˜ξ™•ξ™„ξ™—ξ™ˆξ˜ƒξ™•ξ™ˆξ™„ξ™‡ξ™Œξ™‘ξ™Šξ˜ξ˜ƒξ™–ξ™‹ξ™˜ξ™—ξ˜ƒξ™’σ°€¨ξ˜ƒξ™„ξ™ξ™ξ˜ƒξ™’ξ™—ξ™‹ξ™ˆξ™•ξ˜ƒξ™Šξ™„ξ™–ξ˜ƒ
appliances connected to meter.
TABLE 11
Unit in Btu’s
Seconds for
Natural
Seconds for
Propane
130,000 28 69
180,000 20 ξ˜˜ξ˜“
240,000 ξ˜”ξ˜˜ 37
6-Heat Exchanger
ξ˜·ξ™’ξ˜ƒξ˜€ξ™†ξ™†ξ™ˆξ™–ξ™–ξ˜ƒξ™’ξ™•ξ˜ƒξ˜΅ξ™ˆξ™ξ™’ξ™™ξ™ˆξ˜ƒξ˜«ξ™ˆξ™„ξ™—ξ˜ƒξ˜¨ξ™›ξ™†ξ™‹ξ™„ξ™‘ξ™Šξ™ˆξ™•ξ˜ƒξ˜©ξ™•ξ™’ξ™ξ˜ƒξ˜Έξ™‘ξ™Œξ™—ξ˜
1 - ξ˜ƒξ˜·ξ™˜ξ™•ξ™‘ξ˜ƒξ™’σ°€¨ξ˜ƒξ™Šξ™„ξ™–ξ˜ƒξ™„ξ™‘ξ™‡ξ˜ƒξ™ˆξ™ξ™ˆξ™†ξ™—ξ™•ξ™Œξ™†ξ˜ƒξ™“ξ™’ξ™šξ™ˆξ™•ξ˜‘
2 - ξ˜ƒξ˜΅ξ™ˆξ™ξ™’ξ™™ξ™ˆξ˜ƒξ™„ξ™†ξ™†ξ™ˆξ™–ξ™–ξ˜ƒξ™“ξ™„ξ™‘ξ™ˆξ™ξ˜‹ξ™–ξ˜Œξ˜ƒξ™„ξ™‘ξ™‡ξ˜ƒξ™˜ξ™‘ξ™Œξ™—ξ˜ƒξ™†ξ™ˆξ™‘ξ™—ξ™ˆξ™•ξ˜ƒξ™ξ™˜ξ™ξ™ξ™Œξ™’ξ™‘ξ˜‘
3 - Remove gas valve, manifold assembly and burners.
4 - ξ˜ƒξ˜΅ξ™ˆξ™ξ™’ξ™™ξ™ˆξ˜ƒξ™†ξ™’ξ™ξ™…ξ™˜ξ™–ξ™—ξ™Œξ™’ξ™‘ξ˜ƒξ™„ξ™Œξ™•ξ˜ƒξ™Œξ™‘ξ™‡ξ™˜ξ™†ξ™ˆξ™•ξ˜ƒξ™„ξ™‘ξ™‡ξ˜ƒξ›€ξ™˜ξ™ˆξ˜ƒξ™…ξ™’ξ™›ξ˜ƒξ™†ξ™’ξ™™ξ™ˆξ™•ξ˜‘ξ˜ƒ
Pay careful attention to the order in which gaskets
ξ™„ξ™‘ξ™‡ξ˜ƒξ™’ξ™•ξ™ŒξšΏξ™†ξ™ˆξ˜ƒξ™„ξ™•ξ™ˆξ˜ƒξ™•ξ™ˆξ™ξ™’ξ™™ξ™ˆξ™‡ξ˜‘
ξ˜˜ξ˜ƒξ˜ξ˜ƒ Support heat exchanger (to prevent it from falling
ξ™šξ™‹ξ™ˆξ™‘ξ˜ƒξšΏξ™‘ξ™„ξ™ξ˜ƒξ™–ξ™†ξ™•ξ™ˆξ™šξ™–ξ˜ƒξ™„ξ™•ξ™ˆξ˜ƒξ™•ξ™ˆξ™ξ™’ξ™™ξ™ˆξ™‡ξ˜‘ξ˜Œ
6 - Remove screws supporting heat exchanger.
7 - To install heat exchanger, reverse procedure. Be
sure to secure all wires and check plumbing and
burner plate for airtight seal. Screws must be
ξ™—ξ™’ξ™•ξ™”ξ™˜ξ™ˆξ™‡ξ˜ƒξ™—ξ™’ξ˜ƒξ˜–ξ˜˜ξ˜ƒξ™Œξ™‘ξ˜‘ξ˜ξ™ξ™…ξ™–ξ˜‘ξ˜ƒξ™—ξ™’ξ˜ƒξ™ˆξ™‘ξ™–ξ™˜ξ™•ξ™ˆξ˜ƒξ™“ξ™•ξ™’ξ™“ξ™ˆξ™•ξ˜ƒξ™’ξ™“ξ™ˆξ™•ξ™„ξ™—ξ™Œξ™’ξ™‘ξ˜‘
7-Flame Sensing
Flame current is an electrical current which passes from
the ignition control through the sensor electrode during unit
operation. The current passes from the sensor through the
ξ›€ξ™„ξ™ξ™ˆξ˜ƒξ™—ξ™’ξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™Šξ™•ξ™’ξ™˜ξ™‘ξ™‡ξ˜ƒξ™ˆξ™ξ™ˆξ™†ξ™—ξ™•ξ™’ξ™‡ξ™ˆξ˜ƒξ˜‹ξ™ξ™’ξ™†ξ™„ξ™—ξ™ˆξ™‡ξ˜ƒξ™’ξ™‘ξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ›€ξ™„ξ™ξ™ˆξ˜ƒξ™ˆξ™ξ™ˆξ™†-
ξ™—ξ™•ξ™’ξ™‡ξ™ˆξ˜Œξ˜ƒξ™—ξ™’ξ˜ƒξ™†ξ™’ξ™ξ™“ξ™ξ™ˆξ™—ξ™ˆξ˜ƒξ™„ξ˜ƒξ™–ξ™„ξ™‰ξ™ˆξ™—ξ™œξ˜ƒξ™†ξ™Œξ™•ξ™†ξ™˜ξ™Œξ™—ξ˜‘ξ˜ƒξ˜·ξ™‹ξ™ˆξ˜ƒξ™ˆξ™ξ™ˆξ™†ξ™—ξ™•ξ™’ξ™‡ξ™ˆξ™–ξ˜ƒξ™–ξ™‹ξ™’ξ™˜ξ™ξ™‡ξ˜ƒ
ξ™…ξ™ˆξ˜ƒξ™ξ™’ξ™†ξ™„ξ™—ξ™ˆξ™‡ξ˜ƒξ™–ξ™’ξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™—ξ™Œξ™“ξ™–ξ˜ƒξ™„ξ™•ξ™ˆξ˜ƒξ™„ξ™—ξ˜ƒξ™ξ™ˆξ™„ξ™–ξ™—ξ˜ƒξ˜”ξ˜’ξ˜•ξš΄ξ˜ƒξ˜‹ξ˜”ξ˜•ξ˜‘ξ˜šξ˜ƒξ™ξ™ξ˜Œξ˜ƒξ™Œξ™‘ξ™–ξ™Œξ™‡ξ™ˆξ˜ƒ
ξ™—ξ™‹ξ™ˆξ˜ƒξ›€ξ™„ξ™ξ™ˆξ˜ƒξ™ˆξ™‘ξ™™ξ™ˆξ™ξ™’ξ™“ξ™ˆξ˜‘ξ˜ƒξ˜§ξ™’ξ˜ƒξ™‘ξ™’ξ™—ξ˜ƒξ™…ξ™ˆξ™‘ξ™‡ξ˜ƒξ™ˆξ™ξ™ˆξ™†ξ™—ξ™•ξ™’ξ™‡ξ™ˆξ™–ξ˜‘ξ˜ƒξ˜·ξ™’ξ˜ƒξ™ξ™ˆξ™„ξ™–ξ™˜ξ™•ξ™ˆξ˜ƒ
ξ›€ξ™„ξ™ξ™ˆξ˜ƒξ™†ξ™˜ξ™•ξ™•ξ™ˆξ™‘ξ™—ξ˜ξ˜ƒξ™‰ξ™’ξ™ξ™ξ™’ξ™šξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™“ξ™•ξ™’ξ™†ξ™ˆξ™‡ξ™˜ξ™•ξ™ˆξ˜ƒξ™’ξ™‘ξ˜ƒξ™—ξ™‹ξ™ˆξ˜ƒξ™‰ξ™’ξ™ξ™ξ™’ξ™šξ™Œξ™‘ξ™Šξ˜ƒξ™“ξ™„ξ™Šξ™ˆξ˜
NOTE-Electrodes are not eld adjustable. Any alterations
to the electrode may create a hazardous condition that
can cause property or personal injury.
1 - Disconnect power to unit.
2 - Remove lead from sensing electrode and install
ξ™„ξ˜ƒ ξ˜“ξ˜ξ˜˜ξ˜“ξ˜§ξ˜¦ξ˜ƒ ξ™ξ™Œξ™†ξ™•ξ™’ξ™„ξ™ξ™“ξ˜ƒ ξ™ξ™ˆξ™—ξ™ˆξ™•ξ˜ƒ ξ™Œξ™‘ξ˜ƒ ξ™–ξ™ˆξ™•ξ™Œξ™ˆξ™–ξ˜ƒ ξ™…ξ™ˆξ™—ξ™šξ™ˆξ™ˆξ™‘ξ˜ƒ ξ™—ξ™‹ξ™ˆξ˜ƒ
sensing electrode and the sensing lead.
3 - Reconnect power and adjust thermostat for heating
demand.
4 - ξ˜ƒξ˜Ίξ™‹ξ™ˆξ™‘ξ˜ƒ ξ›€ξ™„ξ™ξ™ˆξ˜ƒ ξ™Œξ™–ξ˜ƒ ξ™ˆξ™–ξ™—ξ™„ξ™…ξ™ξ™Œξ™–ξ™‹ξ™ˆξ™‡ξ˜ξ˜ƒ ξ™ξ™Œξ™†ξ™•ξ™’ξ™„ξ™ξ™“ξ˜ƒ ξ™•ξ™ˆξ™„ξ™‡ξ™Œξ™‘ξ™Šξ˜ƒ
ξ™–ξ™‹ξ™’ξ™˜ξ™ξ™‡ξ˜ƒξ™…ξ™ˆξ˜ƒξ˜“ξ˜‘ξ˜˜ξ˜ƒξ™—ξ™’ξ˜ƒξ˜”ξ˜‘ξ˜“ξ˜‘ξ˜ƒξ˜§ξ™’ξ˜ƒξ™‘ξ™’ξ™—ξ˜ƒξ™…ξ™ˆξ™‘ξ™‡ξ˜ƒξ™ˆξ™ξ™ˆξ™†ξ™—ξ™•ξ™’ξ™‡ξ™ˆξ™–ξ˜‘ξ˜ƒξ˜§ξ™•ξ™’ξ™“ξ˜ƒ
out signal is .09 or less.
ξ˜˜ξ˜ƒξ˜ξ˜ƒ Disconnect power to unit before disconnecting
meter. Make sure sensor wire is securely
reconnected before reconnecting power to unit.
NOTE-If the meter scale reads 0, the leads are reversed.
Disconnect power and reconnect leads for proper polarity.
D-Cooling System Service Checks
LDT units are factory charged and require no further ad-
ξ™ξ™˜ξ™–ξ™—ξ™ξ™ˆξ™‘ξ™—ξ˜žξ˜ƒξ™‹ξ™’ξ™šξ™ˆξ™™ξ™ˆξ™•ξ˜ξ˜ƒξ™†ξ™‹ξ™„ξ™•ξ™Šξ™ˆξ˜ƒξ™–ξ™‹ξ™’ξ™˜ξ™ξ™‡ξ˜ƒξ™…ξ™ˆξ˜ƒξ™†ξ™‹ξ™ˆξ™†ξ™Žξ™ˆξ™‡ξ˜ƒξ™“ξ™ˆξ™•ξ™Œξ™’ξ™‡ξ™Œξ™†ξ™„ξ™ξ™ξ™œξ˜ƒ
using the approach method. The approach method com-
pares actual liquid temperature with the outdoor ambient
temperature. See Charging - Approach Method section.
NOTE-When unit is properly charged discharge line pres-
sures should approximate those in TABLE 5 through TA-
BLE 9.

Table of Contents

Related product manuals