PUMP CONTACT on LAARS FT 301/399 Models

This bulletin clarifies wiring of a pump to the FT series 301/399 models. The FT series 301/399 boilers are equipped with pump contacts. These contacts are rated for 1.6 amps and a maximum voltage of 120V. If the pump that is wired to the FT boilers "pump" contacts exceeds these electrical ratings, it may cause the control board’s internal fuse to blow. To prevent this, install a 120V isolation relay/contactor (i.e. RIB Relay) to power the pump separately, as shown in drawing below. Reference the installation manual for further clarification on the use of these contacts.

I have also attached the wiring diagram depiction in attachments.

• Related Articles

• LAARS FT 301/399 Cascading Instructions

  LAARS FT 301/399 Cascading Instructions Cascade cables Cascade programming Click on attachment to view

• LAARS FT 301/399 Overview

  LAARS FT 301/399 Overview Dimensions Options Accessories Floor stand Click on attachment to view.

• Cascading the Laars FT Series Floor and Wall HEATING ONLY Boilers

  Cascading the Laars FT Series Floor and Wall HEATING ONLY boilers. https://www.laars.com/images/uploads/products/1349C.pdf

• LAARS FT Wall and Floor Circuit Board DIP SWITCH settings. ALL MODELS.

  LAARS FT Wall and Floor Circuit Board DIP SWITCH settings for all FT Models. See attached file.

• Laars FT Blower Fan Models , Combi MFTCW and Heat Only MFTHW

  Blower(Fan) models Thursday June 11, 2020 7:00 AM MFTCW140= FT1407 (Serial #'s F1800309-Present) (Two Vacuum Tube APS -closed barb) (Revision 24) *New Style* MFTCW140= FT1405 (Serial #'s F1500000-F1800308) (Single Vacuum Tube APS-open barb) (Revision ...