Triac/Thyristor delay off timer.

[Tom]

I'm looking for a circuit for switching off a Central heating pump after a
delay up to (max) 2 mins adjustable (after boiler has ceased firing) using
SCR , Triac or similar, 240 V @ 2Amps approx max.
regards
Tom

 

[NSM]

| I'm looking for a circuit for switching off a Central heating pump after a
| delay up to (max) 2 mins adjustable (after boiler has ceased firing) using
| SCR , Triac or similar, 240 V @ 2Amps approx max.

You should be able to find an industrial timer to do this.

N

 

[Andrew Gabriel]

I'm looking for a circuit for switching off a Central heating pump after a
delay up to (max) 2 mins adjustable (after boiler has ceased firing) using
SCR , Triac or similar, 240 V @ 2Amps approx max.

You can buy run-on timers for bath/shower room fans.
You might have to uprate the triac as such fans are
normally only around 20W. Standard domestic central
heating pumps are normally only up to around 120W
on max setting which is a lot less than your 2A.

 

[Tom]

I'm looking for a circuit for switching off a Central heating pump after
a

You can buy run-on timers for bath/shower room fans.
You might have to uprate the triac as such fans are
normally only around 20W. Standard domestic central
heating pumps are normally only up to around 120W
on max setting which is a lot less than your 2A.
Andrew Gabriel

Thanks Andrew, I like to have a high factor of safety in my little circuits,
for a one off for my own use the extra cost is immaterial.
However, Set square has come up with a nice solution on uk.d-i-y using a
pipe stat.
I think it may work, any observations?
Best Regards
Tom

 

[James Sweet]

after

120W? More like 1200W for a 1/2HP blower commonly used for circulation with
the heat pump. The condensing unit itself draws significantly more than
that.

 

[Andrew Gabriel]

120W? More like 1200W for a 1/2HP blower commonly used for circulation with
the heat pump. The condensing unit itself draws significantly more than
that.

You're talking about something quite different.