Monthly Archives: December 2008

Universal Twinning Kit

Universal twinning and paralleling of HVAC equipment made simple

Up until recently, twinning or paralleling of multiple HVAC units has been a wiring nightmare for contractors. Now Jackson Systems offers the TK-400 Universal Twinning and Paralleling Kit that is design to allow a single thermostat to control two or even four HVAC units. The TK-400 can be used on common or separate ducted systems with single stage (1 heat / 1 cool), multi-stage (2 heat / 2 cool) and heat pump (3 heat / 2 cool) equipment. Only standard 18 gauge thermostat wire is required and thermostats and equipment can be located up to 300 feet from the TK-400 panel. When HVAC units share a common return and supply duct, backdraft dampers should be installed and thermostat fan operation must be set for electric. The TK-400 greatly reduces installation time and costs far less than other twinning kits on the market. More information on the TK-400 is available on the Jackson Systems website at

TD-17 timer

The TD-17 timer should not be used with our DFK.  When trying to use the TD-17 in series with W1 from the thermostat and W1 on the HP thermostat terminal strip on our DFK (to delay bringing on the auxiliary heat), W1 will not energize on a call for emergency heat.  The TD-17 is a power stealing device that requires a minimum load to close the circuit.  On just a call for emergency heat there is not enough load to close the circuit.  If Y1 is energized first and then the thermostat calls for auxiliary heat, we now have two relays in parallel and now there would be enough loads to close the circuit.  The risk in using a TD-17 with our DFK is the homeowner going straight to emergency and thus we would not be able to bring on the auxiliary heat.

Honeywell Wireless Thermostat Promotion




(2) Prestige systems


(4) Wireless FocusPRO systems

and Receive:

a $25 Gas Card

Call 1.888.652.9663 and reference Promo Code: HWGAS08

Offer good through January 31, 2009

The thermostats must be purchased on the same invoice

Models included: YTHX9321R5003, YTHX9321R5012, YTHX9321R1000, YTHX9321R1011, YTH6320R1015, YTH6320R1001,YTH5320R1017 and YTH5320R1000









The VisionPRO IAQ has a feature in the installation menu, menu # 346,that is a “Duel Fuel Heat Pump Upstage to Furnace Timer”.  This feature allows you to enter a time from 30 minutes to 75 minutes that you want the heat pump to run before brining on the auxiliary heat.  This feature is only available when you choose Fossil fuel back up in choice #200 and thermostat controls backup heat choice # 210.
This means that we will not have the option to time the upstage from the heat pump to the furnace when using our zone boards in dual fuel applications.