LAARS NeoTherm LC NTH (Sizes 1000-1700 MBTU/h) - Installation Manual - Manual

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H2352500B
Customer Service and Product Support: 800.900.9276 • Fax 800.559.1583
Headquarters: 20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.335.3355
1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 • 905.238.0100 • Fax 905.366.0130
www.Laars.com Litho in U.S.A. © Laars Heating Systems 1404 Document 7025B
VARI-PRIME TM : A variable pump control that, when used with a variable speed pump, maintains a user-chosen temperature rise
between the inlet and outlet of the boiler.
GENERAL PCB OPERATION:
1. The desired Delta T can be set to any of the following values by moving or adding jumpers to the (JP2) terminal on the control:
See Figure 2.
15 deg F/8 deg C 20 deg F/10 deg C 25 deg F/13 deg C 30 deg F/ 16 deg C
By adding a second jumper, one on “15 deg F” and one on “20 deg F”, it is possible to achieve 35 deg F /19 deg C.
By adding a second jumper, one on “15 deg F” and one on “25 deg F”, it is possible to achieve 40 deg F/22 deg C.
2. As shipped, the VARI-PRIME has a jumper on the (JP4) terminal, to operate a 0-10 VDC output. If a 4-20 mA output is needed,
move the jumper to the (JP5) terminal.
3. VARI-PRIME can operate in °F or °C. A jumper on the (JP1) terminal has set the default to °F. Remove that jumper for °C.
4 If Main Gas valve is “OFF” AND a call for heat is “TRUE” then the PCB overrides the PID control and runs the pump
output at 100% (10 VDC, or 20 mA).
5. Once the Main Gas valve is energized the PCB will maintain pump output at 100% for 60 seconds to allow the system to stabilize.
Once the 60 second timer has expired, the PCB will then run the pump output speed based on the jumper setpoint.
6. When “T-T” is satisfied, the PCB will run pump at 100% output for the duration of the pump overrun time.
7. The VARI-PRIME PCB has a low end cap to prevent nuisance low flow trips. The cap is factory programmed to 2 VDC.
8. Factory settings are: Degrees - Fahrenheit Output Signal - 0 -10VDC
800.900.9276 • Fax 800.559.1583 (Customer Service, Service Advisors)
20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.335.3355 (Applications Engineering)
1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 • 905.238.0100 • Fax 905.366.0130
www.Laars.com
FOR YOUR SAFETY: This procedure must be performed by a professional service technician, qualified in
hot water boiler installation. Improper connections could create an electrical hazard, which could cause
serious injury, property damage, or death.
Document 7025B Installation Kit
VARI-PRIME TM Installation Kit for
VARI-PRIME TM
Modulating Boilers
Model NTH.
Sizes 1000-1700 MBTU/h
N
EO
T
HERM ®
LC
INSTALLATION INSTRUCTIONS
P.I.D. CONTROL ADJUSTMENT:
With Variable Speed Pumping, the boiler control P.I.D. needs to be
adjusted.
• These settings are found in your NeoTherm controls under:
Advanced Setup>CH Config>CH Config
It is recommended to start with:
P = 20 I =15 D = Factory set-point
Depending on pump sizing and application requirements; these P.I.D.
settings may
need to be used to fine-tune boiler performance.
• Once you have adjusted the P.I.D. contols, then disconnect power source
from boiler.
• Remove front panels from boiler.
• Pull the sliding panel control straight outward, as shown.
Photo 1