Intermatic T101P timer - possible 240 volts application?

[SplashDIY]

Hello everyone,

I am rewiring our system from 120 to 240 volts (new Hayward VS pump and chemistry system going in). As far as I can tell, the T101P mechanical timer cannot be used to switch 240 volt circuits. I was wondering about this - although the timer motor needs to see 120 volts, can terminals 3 and 4 be used to switch a separate line/load? They are not referenced, so are probably redundant (standardized manufacture process for inclusion other models/features)

It looks like I instead need to deploy the T104M timer. (https://www.intermatic.com/Catalog/us/Products/Timer-Controls/Mechanical-Time-Switches/T104M).

Thank you and I hope everyone has had a great week.

 

[ajw22]

Yes, replace the timer guts with a T104M for 240V.

 

[nuttyp]

While many electricians and others find it "irresponsible" to control a 220v device by switching only one leg, it's often done. I don't know if there is a code page that prohibits doing so, but I have seen MANY deployments, for example using the Intermatic RC2343PT pool/spa timer to switch only one leg to the 220V pool pump, also the 220V spa blower. In all those cases, including how they wired mine and several folks near me, the clock is 120V and simply runs from one leg plus a neutral. Even your T101P implies same in ratings, etc. Diagrams of both the T101P and RC2343PT depicting 220V application are attached.

When servicing, nobody should ever assume that a timer in the off position disables all power to the device (in this case a pump). The two-pole breaker does that function. Many disagree, so it's up to you, unless someone chimes in with perhaps a newer code page that disallows it when wiring a new system or re-wiring an old system. However you do it, you'll need the two 120V legs for 240V plus a neutral (for the clock motor).

That said, keep in mind that many VS pumps prefer to always have power, with control and time schedules provided by the pump software. Read your Hayward manual to determine what they prefer, just saying that you may not need the old mechanical timer at all. Among other VS pump "features" (irritations if you ask me) they often go into a priming mode on power cycle. There were times when I really didn't want the pump to enter the repriming cycle - but I don't remember why. Long ago I got tired of the problems (and costs) with VS pumps and now just buy a $250 two speed

Hope that helps!

 

[Jimrahbe]

Long ago I got tired of the problems (and costs) with VS pumps

Ah!! I now understand your screenname...

Thanks,

Jim R.

 

[1poolman1]

Hello everyone,

I am rewiring our system from 120 to 240 volts (new Hayward VS pump and chemistry system going in). As far as I can tell, the T101P mechanical timer cannot be used to switch 240 volt circuits. I was wondering about this - although the timer motor needs to see 120 volts, can terminals 3 and 4 be used to switch a separate line/load? They are not referenced, so are probably redundant (standardized manufacture process for inclusion other models/features)

It looks like I instead need to deploy the T104M timer. (https://www.intermatic.com/Catalog/us/Products/Timer-Controls/Mechanical-Time-Switches/T104M).

Thank you and I hope everyone has had a great week.

There is no switch on terminals 3 and 4. Look on the back.