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13

ADJUSTMENT

There must be sufficient load to operate the boiler at high fire to 

perform the following adjustments. Start the boiler and observe 

proper operating parameters for the system.

Required Tools:

TORX

®

 T40 or 5mm hex wrench

3mm or 7/64in hex wrench
Combustion analyzer

These boilers are equipped with a Honeywell combined gas/air control 

and gas safety shut off control valves. The valve functions in parallel 

with the variable speed combustion blower to supply the correct gas 

air ratio for optimum performance and efficiency. The combustion 

blower speed is controlled automatically and determines the amount 

of negative pressure experienced by the gas safety shut off/control 

valves. The gas/air regulator adjusts gas flow to maintain the proper 

pressure at the outlet nozzle of the associated valve.

SETTING OF THE TEST MODE

On UIM go to main menu, scroll down to user settings and press 

select. Scroll down to MOD mode, press select. Use the up and 

down keys to select options: MIN (MINIMUM FIRING RATE). 

MAX  (MAXIMUM  FIRING  RATE).  MOD  (FOR    AUTOMATIC 

MODULATION MODE). Press select for the desired option. For 

checking the combustion setup on MIN or MAX the boiler will 

remain in this state for ten minutes before defaulting to the MOD 

(modulation) mode.

HIGH FIRE SETTING

NATURAL GAS

8.5 - 11.0% CO

2

PROPANE

9.5 - 12.0% CO

2

Set  boiler  to  the  “Test  Mode  High,”  as  described  above,  to 

achieve maximum firing rate of the boiler. Check combustion 

readings using a combustion analyzer. If combustion readings 

are  not  in  accordance  with  the  chart  above  adjust  the  gas 

valve  as  follows:  remove  the  flat,  round,  blue  plastic  cap 

from  the  cover.  Using  a  3mm  (7/64”)  hex  wrench,  turn  the 

adjustment screw counterclockwise to increase or clockwise 

to decrease gas flow and achieve the desired CO

2

 level. See 

Table  referenced  above  for  correct  settings. There  will  be  a 

slight  time  delay  between  the  adjustment  and  the  response 

of the CO

2

 measuring instrument. Adjust the settings in small 

increments  and  allow  the  combustion  readings  to  stabilize 

before readjusting. When desired adjustments are complete, 

reinstall the blue plastic cap on the cover. Combustion samples 

should  be  taken  in  the  stack  within  two  feet  of  the  boiler.

LOW FIRE SETTING

NATURAL GAS

7.5 - 9.5% CO

2

PROPANE

9.5 - 12.0% CO

2

Set  boiler  to  the  “Test  Mode  Low,”  as  described  above,  to 

achieve minimum firing rate of the boiler. Check combustion 

readings using a combustion analyzer. If combustion readings 

are not in accordance with the chart shown above adjust as 

follows: remove the cap on the gas regulator using a slotted 

screwdriver.  This  will  expose  the  offset  adjustment  screw. 

Using  a  TORX

®

  T40  or  a  5mm  hex  wrench,  carefully  adjust 

the  low  fire  gas  setting  to  achieve  the  CO

2

  level  prescribed 

in  above  reference  table. 

Note:  The  rotation  of  the  Low 

Fire  adjustment  is  opposite  of  the  High  Fire  as  follows: 

Clockwise rotation increases gas flow, counterclockwise 

rotation  decreases  gas  flow.

Adjustments to the offset pressure regulators should not exceed 

1/4  turn  at  a  time  before  allowing  the  readings  to  respond  and 

stabilize.

After proper low fire offset adjustment is made, reinstall the slotted 

cap on the regulator.
Following all gas valve adjustments, check for proper light-off and 

verify correct fuel/air mix and combustion quality throughout the 

entire firing range (from lowest to highest fan speed).

CONTROL SYSTEM

The  EMC  modulation  control  system  is  a  fully  integrated,  state 

of the art electronic control system. It consists of sensors, output 

devices,  a  power  switch,  a  24VAC  transformer,  wiring,  and  the 

following printed circuit boards:
•  Modulation Control Board (MCB), see Figure 2.

•  Power Distribution Board (PDB), see Figure 2.

•  User Interface Module (UIM), see Figure 4.
The  MCB  contains  circuitry  for  both  master  control  and  flame 

control.  Dip  switches  on  the  MCB  are  used  to  configure  the 

system. The User Interface Module (UIM) communicates with the 

user through a set of touch pads and a 4-line, 20-character LCD 

display. The PDB provides connection points for input power, the 

water pump, and the transformer. It also distributes power to the 

system and contains the system fuses.

iCOMM ™ & BAC net COMPATIBLE

VF boilers are compatible with the iCOMM ™ remote monitoring 

system. The iCOMM ™ system hardware and monitoring service is 

purchased separately. It allows users to monitor critical operational, 

diagnostic and energy usage data from a secure web site. The 

iCOMM ™ system can automatically notify selected personnel via 

email and/or cellular phone text messages if operational problems 

or user defined Alert Conditions occur.

iCOMM ™ system hardware is compatible with BACnet compliant 

supervisory controls and building management systems. For more 

information call 888 928-3702.

There are several microcontrollers used on the boards. These control 

the temperature and ignition control functions for the boiler. Inherent 

in the design are the normal operating sequences and safety features 

associated with a gas ignition control system. The system continuously 

performs various diagnostic tests to verify proper appliance and 

control operation. Should an unsafe condition occur, the control will 

shut down the burner and display a red service light as well as indicate 

the cause of the error on the display. The operating programs for the 

system are stored in permanent memory inside the microcontrollers. 

User-selectable operating parameters and a history of detected faults 

are stored in rewritable memory in the microcontrollers. A loss of 

power does not affect either of the memories.

Summary of Contents for VB 1500

Page 1: ...one in your building Immediately call your gas supplier from a neighbor s phone Follow the gas supplier s instructions If you cannot reach your gas supplier call the fire department Installation and s...

Page 2: ...ning Procedure Mechanical Removal of Deposits 22 Replacement Parts 22 LIMITED WARRANTY 23 TABLE OF CONTENTS 2 safe installation use and service 3 APPROVALS 3 GENERAL SAFETY 4 INTRODUCTION 5 INSTALLATI...

Page 3: ...hazardous situation which if not avoided could result in property damage WARNING CAUTION CAUTION DANGER All safety messages will generally tell you about the type of hazard what can happen if you do...

Page 4: ...etup and instructions before lighting Failure to implement the proper setup will result in improper and inefficient operation of the appliance resulting in production of increased levels of carbon mon...

Page 5: ...ion The installation must conform to all instructions contained in this manual and the local code authority having jurisdiction These should be carefully followed in all cases Authorities having juris...

Page 6: ...e horizontally vented gas fueled heating appliance or equipment The sign should read in print size no less than one half 1 2 inch in size GAS VENT DIRECTLY BELOW KEEP CLEAR OF ALL OBSTRUCTIONS INSPECT...

Page 7: ...DB F3 7 5 AMP FUSE MCB II F1 24VDC GENERATION MCB II K6 RELAY COIL MCB II MR HIGH LIMIT FLOW SWITCH LWCO SWITCH OPTIONAL LOW GAS SWITCH HIGH GAS SWITCH OPTIONAL EXTERNAL ENABLE OPTIONAL POWER ACC PROV...

Page 8: ...LE EXT ENABLE DISABLE COM NO COM NC NO COM COM NC ON OFF POWER RELAY NO COM G W W BK BK BK BK BK W 24VAC HOT W BK 24VAC RTN G GROUND F CAT 5 CABLE R G BK W MCB II DETAIL A Part of J BOX VB VW 1500 200...

Page 9: ...W UNITS COME EQUIPPED WITH PUMP VB UNITS DO NOT 24VAC COM PUMP RELAY A BK F 0 WIRING DIAGRAM TRANSFORMER 120 24 VAC MODULATING CONTROL BOARD II MCB II J20 or J21 J16 1 2 6 7 J24 F1 7 5A 24VAC J3 1 2 3...

Page 10: ...and permit pressure to be established by the pressure reducing valve 2 Vent all high points in system to purge system of air Provisions should be made to permit manual venting of radiators or convecto...

Page 11: ...water temperature or 20 F 11 C differential whichever has the higher inlet temperature is attained b If the inlet water temperature is greater than 120 F 49 C and the 20 F 11 C differential is not pre...

Page 12: ...12 LIGHTING AND OPERATING INSTRUCTIONS...

Page 13: ...efully adjust the low fire gas setting to achieve the CO2 level prescribed in above reference table Note The rotation of the Low Fire adjustment is opposite of the High Fire as follows Clockwise rotat...

Page 14: ...t will operate with the voltage and current level provided Pump MCB 120VAC required on systems that do not have an external pump Provides electrical power to directly operate a pump or the coil of an...

Page 15: ...idle state as displayed by the Standby LED The control will continue to monitor heat demand and state of other system devices Upon a drop of water temperature below the set parameters the control wil...

Page 16: ...when the fault state is exited Hard Fault State See Fault Description section for list of soft and Auto Reset faults The pump remains on for the selected post circulate time to cycle the hot water ou...

Page 17: ...soft lockout condition will occur and burner will be shut off This fault condition is automatically cleared when temperature drops below high limit setpoint minus high limit differential AUTO HIGH LI...

Page 18: ...nwards in screens to reach a desired item and to change setpoints and user settings They have an auto increment decrement feature for some of the configurations and values When you first press one of...

Page 19: ...the MCB and reading the resistance across the two active pinsontheconnectoratthe end of the probe cable The value should be approximately 0 ohms when the temperature of the probe is less than 220 F L...

Page 20: ...unction of the servo pressure regulator Replace the valve and add a gas filter in front of the new valve preventative maintenance This is a pre mix burner system The flame is not supposed to be direct...

Page 21: ...to move at this point FOR DIRECT VENT UNITS It is necessary to loosen and slide the rubber coupling on the blower adaptor in order to move the blower 4 Loosen the seven bolts on the blower adapter at...

Page 22: ...xist As the water is heated these tend to drop out depositing as scale or lime This scale must be removed before the heat exchanger tubes become blocked DELIMING The amount of calcium carbonate lime r...

Page 23: ...his boiler under state or provincial law are limited to one 1 year duration for the boiler or any of its parts Some states and provinces do not allow limitations on how long an implied warranty lasts...

Page 24: ...24 500 Tennessee Waltz Parkway Ashland City TN 37015 Technical Support 800 527 1953 Parts 800 433 2545 Fax 800 644 9306 www hotwater com...

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