This is accomplished by changing two dipswitch settings on the MCB. First, dipswitch “4” must be set to the “ON” position to designate the remote probe as the controlling probe. Second, dipswitch “1” must be set to the “OFF” position to limit the maximum remote probe temperature for VW applications. Also, make sure dipswitch “1” is set to the “OFF” position, which sets the outlet temperature for VW applications. Failure to do this will void the warranty. If the remote probe is not designated as the controlling probe, the unit will be controlled by the inlet probe and will not use the desired tank temperature as its base.
Refer to Connection Diagram, Figure 17, in order to connect the remote probe to the boiler, see Tables 9, 10, 13 and 14 for Dipswitch positions.
Gas Connections
Make sure the gas on which the boiler is to operate is the same as that specified on the rating plate. Do not install the boiler if equipped for a different type of gas. Consult your gas supplier.
This boiler is not intended to operate at gas supply pressure other than shown on the rating plate. A lock-up or positive shut-off type regulator must be installed in the gas supply line. Exposure to higher gas supply pressure may cause damage to gas valves which can result in fire or explosion. If overpressure has occurred such as through improper testing of gas lines or emergency malfunction of the supply system, the gas valves must be checked for safe operation. Make sure that the outside vents on the supply regulators and the safety vent valves are protected against blockage. These are parts of the gas supply system, not the boiler. Vent blockage may occur during ice build-up or snowstorms.
The boiler must be isolated from the gas supply piping system by closing its main manual gas shut-off valve during any pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 psig.
Disconnect the boiler and its main manual gas shut-off valve from the gas supply piping during any pressure testing of the gas supply system over 1/2 psig. The gas supply line must be capped when not connected to the boiler.
It is important to guard against gas valve fouling from contaminants in the gas ways. Such fouling may cause improper operation, fire or explosion. If copper supply lines are used they must be approved for gas service.
When local codes require a main manual shut-off valve outside the boiler jacket, a suitable main manual shut-off valve must be installed in a location complying with those codes.
Before attaching the gas line be sure that all gas pipe is clean on the inside.
To trap any dirt or foreign material in the gas supply line, a drip leg (sediment trap) must be incorporated in the piping. The drip leg must be readily accessible and not subject to freezing conditions. Install in accordance with recommendations of serving gas supplier. Refer to the current edition of the national fuel gas code, ANSI Z223.1 or CAN/CSA – B149.1, and current addenda.
Size of gas supply piping may be larger than heater connection on installations where a significant run of piping is required.
To prevent damage, care must be taken not to apply too much torque when attaching gas supply pipe to boiler gas inlet.
Fittings and unions in the gas line must be of the metal to metal type.
Apply joint compounds (pipe dope) sparingly and only to the male threads of pipe joints. Do not apply compound to the first two threads. Use compounds resistant to the action of liquefied petroleum gases.
Gas Supply Line Sizing
The gas piping installation must be capable of supplying the maximum probable gas demand without excessive pressure loss. Depending on local practices, the ALLOWABLE PRESSURE LOSS between the gas meter, or service regulator and each appliance is generally 0.3 or 0.5 inches of water column (0.075 or 0.124kPa).
For single boiler installation, refer to Table 5 for appropriate pipe length for the appliance maximum rate.
For multiple boilers refer to Table 6 for natural gas and Table 7 for propane. Maximum pressure drop is 0.5 for these charts.
Reference tables are from ANSI Z223.1 National Fuel Gas Code or CAN/CSA-B149.1-00 (and current addenda):
Natural gas is 1000 BTU/ft^3 @ 0.6 specific gravity Propane gas is 2500 BTU/ft^3 @ 1.5 specific gravity
< pipe length longer than 200 feet consult applicable codes
No additional allowance is necessary for an ordinary number of fittings. Where it is necessary to use more than the average number of fittings (i.e., elbows, tees and valves in gas supply line) use a pipe larger than specified to compensate for increased pressure drop.
TABLE 5.
SINGLE UNIT INSTALLATION, SUGGESTED GAS PIPE SIZING.
MAXIMUM EQUIVALENT PIPE LENGTH (IN FEET).
Nom. Pipe | | | | | 0.3 in w.c. drop | | | | |
| 1” | 1.25” | 1.5” | | 2” |
BTU input | Nat | | Prop | Nat | Prop | Nat | | Prop | Nat | | Prop |
500,000 | 10 | | 25 | 40 | 90 | 80 | | 200 | 200 | | |
750,000 | | | 10 | 10 | 40 | 40 | | 90 | 125 | | < |
1,000,000 | | | | 10 | 20 | 20 | | 50 | 70 | | 175 |
Nom. Pipe | | | | | 0.5 in w.c. drop | | | | |
| 1” | 1.25” | 1.5” | | 2” |
BTU input | Nat | | Prop | Nat | Prop | Nat | | Prop | Nat | | Prop |
500,000 | 10 | | 40 | 60 | 150 | 150 | | 200 | < | | |
750,000 | | | 10 | 30 | 70 | 70 | | 150 | 200 | | |
1,000,000 | | | 10 | 10 | 40 | 30 | | 90 | 125 | | < |
