VIESSMANN 7968317 Auxiliary Low Gas Pressure Switch Instruction Manual
- June 8, 2024
- VIESSMANN
Table of Contents
VIESSMANN 7968317 Auxiliary Low Gas Pressure Switch Instruction Manual
Safety and Installation Requirements
Please ensure that these instructions are read and understood before starting any service work. Failure to comply with these instructions may cause product/property damage, severe personal injury and/or loss of life.
Working on the equipment
The installation, adjustment, service and maintenance of this product must be performed by a licensed professional heating contractor who is qualified and experienced in the installation, service, and maintenance of hot water boilers. There are no user serviceable parts on the boiler, burner or control.
Ensure that main power to the equipment being serviced is off. Ensure that the main fuel supply valve to the boiler is closed.
Take precautions to avoid accidental activation of power or fuel during service work.
Do not perform service work on any component part without ensuring safe operation of the heating system. When replacing parts, use original Viessmann or Viessmann approved replacement parts.
Refer to the applicable boiler Installation Instructions.
Installation Steps
IMPORTANT
Low pressure switches are suitable for making and/or breaking a circuit when the medium pressure changes relative to the setpoint. The setpoint can be set in the field by an adjustable dial with an integrated scale.
CAUTION
Low gas pressure can cause the heating system to shut down.
Codes
Refer to current CAN/CSA B149.1 and .2 or National Fuel Gas Code ANSI
Z223.1/NFPA 54, as well as local codes for gas piping requirements and
sizing.Pipe size to the boiler must be determined based on:
- pipe length
- umber of fittings
- type of gas
- maximum input requirements of all gas appliances in the residence.
IMPORTANT
Design piping layout in such a way that piping does not interfere with serviceable components. All electrical wiring is to be done in accordance with the latest edition of CSA C22.1 Part 1 and/or local codes. In the U.S. use the National Electrical Code ANSI/NFPA 70
Installation
B2HA Boiler connection (Multi)| Low gas pressure switch connection| Cable
color
---|---|---
G| F| Green (GN)
L| COM| Black (BK)
1| NO| Red (RD)
N| N| White (WT)
Installation steps
- Disconnect boiler power supply.
- If the boiler has already been installed, shut off main gas supply to the boiler and disconnect gas supply piping.
- Supply and install gas piping components as required (see illustration).
- Make electrical connections as shown between the boiler and the low gas pressure switch as required.
- Set the low gas pressure switch to 4.5” wc.
- Open main gas supply.
- Using an approved gas leak detector, check gas line and low gas pressure switch.
- Restore power to the boiler.
Note: Venting is not required, subject to the authority have jusisdition. The switch has a built-in vent limiter
Operation
When sufficient gas pressure is available, the low gas pressure switch contact terminals 3(COM) and 2(NO) will close. The burner control is then energized and the system will operate normally.
When there is insufficient gas pressure, the low gas pressure switch contact terminals 3(COM) and 2(NO) will open and the burner will stop operating (the indicator light on the pressure switch will be illuminated).
Check the boiler control display for a fault message. If no fault message is displayed on the boiler control, verify that the boiler is not operating due to low gas pressure. Access coding level 2, enter the ‘Boiler’ submenu and scroll to coding address 38. If coding address 38:29 isdisplayed, restart the boiler.
For details on accessing coding levels, refer to Vitodens Service Instructions.
To restart the boiler, press the low gas pressure switch reset button (only once). Return to the home screen and access coding level 2, enter the ‘Boiler’ submenu and scroll to coding address 38. Coding address 38 should now display 38:0. If coding address 38:29 continues to be displayed, verify the gas supply pressure.
There should be a minimum operating pressure of 4.5” w.c. If the operating pressure is lower than 4.5” w.c., contact your local gas company.
Gas Piping Components
Legend
- A Coupling 1”
- B Nipple 1”x 3”
- C Reducing tee 1”x1”xa
- D Manual gas shutoff valve 1″ (supplied with boiler)
- E Nipple a”x1b”
- F Low gas pressure switch
- G Nipple 1”x2”
- H Pressure switch harness (not shown)
Fault Generation
When connected in a Multi-boiler system using a Vitotronic 300 MW2C, a boiler fault signal is required.
Installation steps
- Disconnect boiler power supply.
- If the boiler has already been installed, shut off main gas supply to the boiler and disconnect gas supply piping.
- Install relay (field supplied) by connecting the coil side of the relay to the Normally Closed (NC) position (120VAC) of the LGPS, and the Neutral terminal of the ‘MULTI’ plug
- Connect the Normally Open (NO) position of the relay to terminals DE1, DE2 or DE3 (terminals 1 and 2) of the internal EA1 module.
- Open main gas supply.
- Using an approved gas leak detector, check gas line and low gas pressure switch.
- Restore power to the boiler.
- Access coding level 2 and set address 3A:0 to 3A:4 (for DE1, for DE2 and DE3 set addresses 3B:4 or 3C:4 respectively.
Legend
A Relay (field supplied)
Customer Support
Viessmann Manufacturing Company (U.S.) Inc.
45 Access Road
Warwick, Rhode Island • 02886 • USA
TechInfo Line 1-888-484-8643
1-800-288-0667
Fax 401-732-0590
www.viessmann-us.com
info@viessmann-us.coni
Viessmann Manufacturing Company Inc
.45Acces Road
Warwick,Rhode • 02886 • USA
TechInfo Line 1-888-484-8643
1-800-387-7373 • Fax
519-885-0887
www.viessmann.ca •
info@viessmann.ca
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