Difference Setpoint Control - On/Off Zoom

Difference Setpoint Control - On/Off


Brand: Tekmar

Qty Price
/ each
$479.85 / box (3 units x $159.95)
In Stock at Supplier! Ships in 2-3 Days
(7 Available)



Application: Alternative Energy
Width: 2-7/8"
Height: 4-3/4"
Difference Setpoint
User Interface: Push Button
Depth (Inches): 7/8"
Ambient Conditions: Indoor Only: -20°-120°F < 90% RH non-condensing
Power Supply: 24V (ac)
24V (dc)
Relays: 240 V (ac) 10 A-1/3 hp-pilot duty 240 VA
Max Temp (F): 284°F
Min Temp (F): -76°F
Temperature Range (F): -76°-284°F
Control: Microprocessor Control
Weight (lbs): .7 lbs
Sensors: NTC Thermistor
10 k ohm @ 77°F
Enclosure Type: C

Description for Tekmar 156

Control Description
The Difference Setpoint Control 156 is designed to operate an on/off pump to transfer heat from a heat source to a storage tank. The control operates based on a setpoint temperature difference (ΔT). The relay turns on when the ΔT rises above the setpoint and turns off when the ΔT falls below the setpoint less the differential. The Source Minimum and Storage Maximum settings turn off the relay when heat transfer is no longer desirable. Potential applications include using solar collectors or a wood boiler as a heat source.

  • Literature: D 156, A 156, D 001, D 070
  • Control: Microprocessor control; This is not a safety (limit) control
  • Packaged Weight: 0.8 lb. (360 g)
  • Enclosure: C, White PVC plastic
  • Dimensions: 4-3/4" H x 2-7/8" W x 7/8" D (120 x 74 x 22 mm)
  • Approvals: CSA certified to CSA 22.2 No 24 and UL 873
  • Ambient Conditions: Indoor use only, -20 to 120¼F (-30 to 50¼C), < 90% RH non-condensing
  • Power Supply: 24 V ¼10% 50/60 Hz 2 VA, 24 V (dc) ¼10% 0.04 A
  • Relay: 240 V (ac) 10 A 1/3 hp, pilot duty 240 VA
  • Sensors Included
  • NTC thermistor, 10 komega @ 77¼F (25¼C ¼0.2¼C) +=3892 Two of Universal Sensor 071

Difference Setpoint Control - On/Off


by PowerReviews
TekmarDifference Setpoint Control - On/Off

(based on 3 reviews)

Ratings Distribution

  • 5 Stars



  • 4 Stars



  • 3 Stars



  • 2 Stars



  • 1 Stars




of respondents would recommend this to a friend.

Reviewed by 3 customers

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wide range of uses.

By Nigel from Canada.

from Thunder Bay, ON.

Verified Reviewer

Comments about Difference Setpoint Control - On/Off:

Using this control with an indirect 80 gallon DHW pre-heat tank, where the source is a GEO thermal buffer tank that can also be heated by outdoor wood furnace. This control works flawlessly. When there is more heat in the source than in the storage, it comes on! When there is less heat in the source than in the storage, it doesn't come on and needlessly run the zone. Set it once and forget it. Now I can warm up well water from 40 degrees to 110 degrees with the heat pump before it goes into the electric hot water tank, saving me kWh. Using the outdoor wood furnace, I can get the pre-heat tank up to 155 degrees before it mixes with the electric tank, and save even more kWh.

  • Primary use:
  • Personal

Works good

By BrnmccO1

from Indiana, USA

Verified Reviewer

Comments about Difference Setpoint Control - On/Off:

Using with a solar evacuated tube system

  • Primary use:
  • Business

Tekmar 156 does it all

By Scott

from Blanchardville, WI.

Verified Buyer

Comments about Difference Setpoint Control - On/Off:

The Tekmar 156 is the perfect control for a home based solar water heating system. Mounted next to my house thermostat, the read-outs tell me everything I want to know about how my system is operating, and at the same time completely automating the control of my circulating pump for maximum efficiency. Once installed, you just sit back and let the control run the system.

  • Primary use:
  • Personal

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1 Question | 1 Answer
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  • Difference Setpoint Control - On/Off


    does product include sensors?
    Asked on 2/24/2011 by Kevin from Canada

    1 answer



      Yes, it includes Solar Sensor 085 and Universal Sensor 071.

      Answered on 2/25/2011 by PexSupply Staff from NY
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