58
begin alternating between SEP and CH and the central heating pump will come on. If you then
press
{S2}
, the central heating pump will shut off, the display will begin alternating between SEP
and DH, and the DHW pump will come on. If the boiler is set up as the cascade master and you
press the
{S2}
key again, the DHW pump will shut off, the display will begin alternating between
SEP and Sh, and the system pump will come on. By using the
{S1}
and
{S2}
keys in this manner,
you can toggle between running each pump in the system as required to help bleed out all
entrapped air. Some good indicators that air is removed include the absence of gurgling noises in
the pipes and pump operation becoming very quiet. Pressing
{S1}
and
{S2}
together at any time
will return the boiler control to normal operation.
i. After the system has operated for awhile, eliminate any residual air by using the manual air
vents located throughout the system.
j. If purge valves are not installed in the system, open manual air vents in the system one at a
time beginning with the lowest floor. Close vent when water squirts out. Repeat with remaining
vents.
k. Refill to correct pressure.
E. CHECK FOR GAS LEAKS
Before starting the boiler, and during initial operation, smell near the floor and around the boiler for gas
odorant or any unusual odor. Remove boiler front door and smell interior of boiler enclosure. Do not
proceed with startup if there is any indication of a gas leak. Repair any leaks at once.
PROPANE BOILERS ONLY – Propane suppliers mix an odorant with the propane to make its presence
detectable. In some instances, the odorant can fade, and the gas may no longer have an odor. Before
startup (and periodically thereafter), have the propane supplier verify the correct odorant level in the gas.
F. CHECK THERMOSTAT CIRCUIT(S)
1. Disconnect the two external wires connected to the boiler thermostat terminals (low voltage terminal
strip).
2. Connect a voltmeter across these two incoming wires with power applied to the thermostat circuits.
Close each thermostat, zone valve, and relay in the external circuit one at a time and check the voltmeter
reading across the incoming wires.
3. There should NEVER be a voltage reading.
4. If a voltage reading does occur under any condition, check and correct the external wiring. (This is a
common problem when using 3-wire zone valves).
5. Once the external thermostat circuit wiring is checked and corrected if necessary, reconnect the
external thermostat circuit wires to boiler low voltage terminal strip. Allow the boiler to cycle.
G. CONDENSATE REMOVAL
1. The boiler is a high efficiency condensing boiler. Therefore, the unit has a condensate drain.
Condensate fluid is nothing more than water vapor, derived from combustion products, similar to that
produced by an automobile when it is initially started.
Condensation is slightly acidic (typically with a pH of 3 to 5) and must be piped with the correct materials.
Never pipe the condensate using steel, copper, brass or other materials that will be subject to corrosion.
Plastic PVC or CPVC pipe are the only approved materials.
Summary of Contents for Mod Con 300 HL
Page 13: ...13 Figure 2 ...
Page 31: ...31 Figure 13 ...
Page 37: ...37 J SIDEWALL VENTING DIAGRAMS Figure 16 Sidewall Venting with Tee and Coupling ...
Page 38: ...38 Figure 17 Sidewall Venting Diagrams ...
Page 39: ...39 K VERTICAL VENTING DIAGRAMS Figure 18 Two Pipe Roof Venting with Tee and Coupling ...
Page 40: ...40 Figure 19 Roof and Sidewall Venting with Stainless Steel ...
Page 44: ...44 E GAS VALVE Figure 21 ...
Page 45: ...45 Figure 22 ...
Page 55: ...55 Figure 28 Mod Con Internal Connection Diagram ...
Page 73: ...73 Figure 32 ...
Page 74: ...74 Figure 33 ...
Page 75: ...75 Figure 34 ...
Page 76: ...76 Figure 35 ...
Page 77: ...77 Figure 36 ...
Page 80: ...80 ...
Page 81: ...81 ...
Page 82: ...82 MAINTENANCE NOTES ...
