Raypak 504-2004 - Manual (Page 2)

Project Name / Date Division 23 34 36.29 - 2
2. Product: MVB
®
copper finned-tube domestic water heater(s)
2.2 WATER HEATERS
A. General
1. The water heater(s) shall be fired with gas at a rated input of BTU/hr.
2. The water heater(s) shall be CSA tested and certified with a minimum thermal efficiency of 84
percent at full fire on Models 504 and 754, and 85 percent on Models 1104, 1504 and 2004.
3. The water heater(s) shall be ASME inspected and stamped and National Board registered for
160 PSIG working pressure and 210ºF maximum allowable temperature, complete with a
Manufacturer's Data Report.
4. The water heater(s) shall have a floor loading of 185 lbs./square foot or less.
B. Heat Exchanger
1. The heat exchanger shall be of a single-bank, vertical multi-pass design and shall completely
enclose the combustion chamber for maximum efficiency. The tubes shall be set vertically and
shall be rolled into a powder coated, ASME water heater quality, carbon steel tube sheet.
2. The heat exchanger shall be sealed to 160 PSIG rated bronze headers with silicone "O" rings,
having a temperature rating over 500°F.
3. The low water volume heat exchanger shall be explosion-proof on the water side and shall
carry a twenty-year warranty against thermal shock.
4. The headers shall be secured to the tube sheet by stud bolts with flange nuts to permit
inspection and maintenance without removal of external piping connections. A heavy gauge
stainless steel slotted heat exchanger wrap shall ensure proper combustion gas flow across
the copper finned-tubes.
5. The water heater(s) shall be capable of operating without harmful condensation at inlet water
temperatures as low as 120°F with a copper heat exchanger, and 105°F with a cupro nickel
heat exchanger.
6. The water heater(s) flue connection, combustion air opening, gas connection, water
connections and electrical connections shall be located on the rear.
7. The primary heat exchanger shall have accessible water heater drain valves with hose bibs to
drain the water section of the primary heat exchanger.
C. Burners
1. The combustion chamber shall be of the sealed combustion type employing the Raypak high
temperature FeCrAloy woven mesh burner, mounted in a vertical orientation.
2. The burner must be capable of firing at 100% of rated input when supplied with 4.0” WC of
inlet gas pressure, so as to maintain service under heavy demand conditions; no exceptions.
3. The burner shall use a combustion air blower to precisely control the fuel/air mixture for
maximum efficiency. The combustion air blower shall operate for a pre-purge period before
burner ignition and a post-purge period after burner operation to clear the combustion
chamber.
4. The blower shall set its output in response to a 4-20mA signal supplied directly from the PID
temperature controller, thereby electronically and precisely adjusting the volume of air and gas
supplied for combustion. Minimum fire shall be 100
percent of rated input. (Ignition will occur at
50% of rated input. Once the proof of flame signal is received by the PID temperature
controller, the water heater is released to operate within normal parameters).
D. Control System
1. The water heater(s) shall be equipped with a 100 percent safety shutdown.
2. The ignition shall be Hot Surface Ignition type with full flame rectification by remote sensing
separate from the ignition source, with a three-try-for-ignition sequence, to ensure consistent
operation.
3. The igniter will be located to the side of the heat exchanger to protect the device from
condensation during start-up.
4. The ignition control module shall include an LED that indicates six (6) individual diagnostic
flash codes.
5. An external viewing port shall be provided, permitting visual observation of burner operation.