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can a variable speed controller run a relay?

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mtmtntop

New Member
i have a tekmar 157 controller which runs the primary pump for a solar array at a variable speed. i was wondering if i can run a 120 v relay off of this lead. i am unsure if varying the speed affects the voltage or amperage. if it reduces the voltage, i do not think it can operate the coil. anyone know? thanks
 

Willbe

New Member
i have a tekmar 157 controller which runs the primary pump for a solar array at a variable speed. i was wondering if i can run a 120 v relay off of this lead. i am unsure if varying the speed affects the voltage or amperage. if it reduces the voltage, i do not think it can operate the coil. anyone know? thanks
tekmar Difference Setpoint Control 157
I can't tell from this link.
Relays generally pull in at 2/3rds rated voltage and drop out at 1/3rd rated v.
 

kchriste

New Member
Forum Supporter
Can you use the secondary pump output in Mode1 to drive the relay?

The 157 has a second 120 V (ac) powered output wired
through the back of the control for an on/off pump. The
second pump has 4 adjustable modes of operation
depending on the application.

Mode 1 Heat Exchanger is for applications where the
heat exchanger pump is needed to transfer heat between
an external heat exchanger and the storage tank. The heat
exchanger pump relay will operate whenever the variable
speed pump is above 0% output. Refer to application
A157-2.
 
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mtmtntop

New Member
no, that won't work. i wanted to open a zone valve when the primary pump was activated. it looks like i may have to do this via an aquastat and temp sensor.
 

mtmtntop

New Member
on second thought maybe it will. re reading your post, it has power whenever the pump 1 is operating greater than zero. i hadn't thought of using the p2 lead. thanks alot! i guess i need to read the instructions more creatively next time.
 
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