UTICA BOILERS UB90-125 Installation, Operation & Maintenance Manual page 4

Ratings shown are for sea level applications. Boiler automatically derates input as altitude
increases. No alterations to boiler are required for altitudes above sea level.
Nominal
Input
3" Vent Lengths
Altitude
0 200,000
1,000 197,000
2,000 194,000
3,000 191,000
4,000 188,000
5,000 185,000
6,000 182,000
7,000 179,000
8,000 176,000
9,000 173,000
10,000 170,000
Nominal
Input
3" Vent Lengths
Altitude
0 200,000
1,000 195,900
2,000 191,800
3,000 187,700
4,000 183,600
5,000 179,500
6,000 175,400
7,000 171,300
8,000 167,200
9,000 163,100
10,000 159,000
This is gas-fired direct vent cast aluminum hot water boiler. Cast aluminum heat exchanger means better heat transfer
and thermal storage than similarly sized cast iron boilers, which results in higher efficiency. Heating system water
absorbs large amounts of heat from cast aluminum heat exchanger, cooling flue gases and causing condensation. Sealed
combustion, premix gas burner, and low flame temperature means drastically reduced CO and NOx emissions, which
contribute to cleaner and healthier environment.
Appliance, unlike normal residential atmospheric and induced draft units, takes its combustion air directly from outdoors
(sealed combustion) and does not compete with building occupants for fresh air. Sealed combustion (also known as "direct
vent") is safest and best way to obtain plenty of clean combustion air. Forced draft fan draws in outside combustion air to
mix with gas, which flows into pre-mix burner and combusts. Fan forces resulting flue gases from boiler unit and provides
positive removal of flue gases from building through choice of PVC, CPVC or PP vent pipes. (Refer to Table 7 page 18 for
material limitations.)
1 - BOILER RATINGS & CAPACITIES
Table 2
200,000
3" Vent Lengths
Min Max
200,000 175,000
196,500 172,400
193,000 169,800
189,500 167,200
186,000 164,600
182,500 162,000
179,000 159,400
175,500 156,800
172,000 154,200
168,500 151,600
165,000 149,000
200,000
3" Vent Lengths
Min. Max
200,000 175,000
195,750 171,900
191,500 168,800
187,250 165,700
183,000 162,600
178,750 159,500
174,500 156,400
170,250 153,300
166,000 150,200
161,750 147,100
157,500 144,000
- NATURAL GAS
175,000
3" Vent Lengths
Min. Max
175,000 150,000
172,200 147,800
169,400 145,600
166,600 143,400
163,800 141,200
161,000 139,000
158,200 136,800
155,400 134,600
152,600 132,400
149,800 130,200
147,000 128,000
Table 3 - LP GAS
175,000
3" Vent Lengths
Min. Max
175,000 150,000
171,200 146,900
167,400 143,800
163,600 140,700
159,800 137,600
156,000 134,500
152,200 131,400
148,400 128,300
144,600 125,200
140,800 122,100
137,000 119,000
4
150,000
3" Vent Lengths
Min. Max
150,000 125,000
147,400 123,500
144,800 122,000
142,200 120,500
139,600 119,000
137,000 117,500
134,400 116,000
131,800 114,500
129,200 113,000
126,600 111,500
124,000 110,000
150,000
3" Vent Lengths
Min. Max
150,000 125,000
146,700 123,050
143,400 121,100
140,100 119,150
136,800 117,200
133,500 115,250
130,200 113,300
126,900 111,350
123,600 109,400
120,300 107,450
117,000 105,500
125,000
Min. Max
125,000
123,000
121,000
119,000
117,000
115,000
113,000
111,000
109,000
107,000
105,000
125,000
Min. Max
125,000
122,250
119,500
116,750
114,000
111,250
108,500
105,750
103,000
100,250
97,500