Raypak 302B, 902B manual Relief Valve Piping, Hydrostatic Test, Cold Water Operation

5.Remove all plumbing fittings to the header. This will include both inlet and outlet water pipe unions and the pressure relief valve and drain piping.

6.Remove limits, control bulbs and/or thermocou- ples.

7.Remove the six flange nuts and the in/out header from the left-hand side.

8.Remove the six flange nuts and the return header from the right-hand side.

9.Remove the header stud bolts from each tube sheet.

10.Reverse the headers and stud bolts to the new location.

11.Install NEW red beveled O-rings flush against both tube sheets with the bevel facing outward.

12.Push the header firmly against the O-rings. Install and tighten the flange nuts onto the stud bolts until finger tight.

13.Slowly tighten the flange nuts, starting from the center nut (number 1) in Fig. 9 and working se- quentially around the header as indicated. Torque all nuts to 25 ft/lb. DO NOT OVER-TIGHTEN.

14.Re-route the capillary(s), wiring etc. to the new location, adding thermal paste and shim to the capillary well.

Fig. 9: Torque Sequence

Relief Valve Piping

WARNING: Pressure relief valve discharge piping must be piped near the floor and close to a drain to eliminate the potential of severe burns. Do not pipe to any area where freezing could occur. Refer to local codes.

Hydrostatic Test

Unlike many types of heaters, this heater does not re- quire hydrostatic testing prior to being placed in operation. The heat exchanger has already been fac- tory-tested and is rated for 160 psi operating pressure. However, Raypak does recommend hydrostatic test- ing of the piping connections to the heater and the rest of the system prior to operation. This is particularly true for hydronic systems using expensive glycol- based anti-freeze. Raypak recommends conducting the hydrostatic test before connecting gas piping or electrical supply.

Leaks must be repaired at once to prevent damage to the heater. NEVER use petroleum-based stop-leak compounds.

To perform hydrostatic test:

1.Connect fill water supply. With bleed valve open, fill heater with water. When water flows from bleed valve, shut off water. Close bleed valve. Carefully fill the rest of the system, making sure to eliminate any entrapped air by using high-point vents. Close feed valve. Test at standard operating pressure for at least 24 hours.

2.Make sure constant gauge pressure has been maintained throughout test.

3.Check for leaks. Repair if found.

Cold Water Operation

CAUTION: Damaging internal condensation may occur if the heater inlet water temperature does not exceed 105ºF (41ºC) within 7 minutes of start-up.

NOTE: See Raypak Catalog No. 1000.57 for infor- mation on Cold Water Protection.

A heater operated with an inlet temperature of less than 105ºF (41ºC) must have a manual bypass or an approved low-temperature operation system to pre- vent problems with condensation. A manual bypass, shown in Fig. 15, must be piped into the system at the time of installation. This piping is like a primary/sec- ondary boiler installation with a bypass acting as the secondary boiler piping. Raypak strongly recommends that thermometer(s) be placed into the heater piping next to the in/out header to facilitate temperature adjustment. Inlet water temperatures below 105ºF (41ºC) can excessively cool the products of combus- tion, resulting in condensation on the heat exchanger and in the flue.

15