Raypak XTHERM 1005 - Manual (Page 2)

Project Name / Date
2.2 POOL HEATERS
A. General
1. The pool heater(s) shall be fired with gas at a rated input of BTU/hr.
2. The pool heater(s) shall be CSA tested and certified with a minimum thermal efficiency of 97
percent at full fire (99% at part load).
3. The pool heater(s) shall be ASME inspected and stamped and National Board registered for
160 PSIG maximum allowable working pressure and 190ºF maximum allowable temperature,
complete with a Manufacturer's Data Report.
4. The pool heater(s) shall have a floor loading of 131 lbs. /square foot or less.
B. Primary Heat Exchanger
1. The primary 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 pool heater quality, carbon steel
tube sheet.
2. The primary 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 primary heat exchanger shall be explosion-proof on the water side and
shall carry a twenty-five-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 primary heat exchanger wrap shall ensure proper combustion gas flow
across the copper-finned tubes.
5. The pool heater(s) flue connection, combustion air opening, gas connection, water
connections, condensate drain and electrical connections shall be located on the rear.
6. The primary heat exchanger shall have accessible pool heater drain valves with hose bibs to
drain the water section of the primary heat exchanger.
C. Secondary Heat Exchanger
1. The secondary heat exchanger shall be a single-bank, multi-pass design constructed of
stainless steel and bears the ASME U stamp.
2. The pool heater(s) shall be capable of operating at inlet water temperatures as low as 50°F.
D. Condensate Drain
1. The heater(s) will feature a condensate drain switch which will shut down the heater(s) if the
condensate drain is blocked.
E. 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 both a complete blue flame with maximum gas and air
input as well as firing infrared when gas and air are reduced. 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 throughout the entire range of modulation. 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 infinitely vary its output in response to a 4-20 mA signal supplied directly from
the PID modulating temperature controller, thereby electronically and precisely adjusting the
volume of air and gas supplied for combustion. Minimum fire shall be 25 percent of rated input.
F. Pilot Control System
1. The pool 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.