Question about Intermatic WH40 - Water Heater Time Switch - NEMA 1 Indoor Steel Case - DPS

3 Answers

HI, HOW TO CONNECT 2 40 AMP CONTACTORS WITH A WH40 TIMER, 2 THERMOSTATS AND 2 ELECTRIC ELEMENTS 9KW EACH.THOSE COMPONENTS ARE USED IN A 18 KW TANKLESS HOT WATER FOR SWIMMING POOL. REASON FOR THIS IS TO DELAY POWER TO HEATER AFTER THE POOL PUMP START AND TURN OFF POWER TO HEATER BEFORE POOL PUMP STOP

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  • dpetroni2006 Apr 01, 2011

    Hi, Silverdragon, tank you for you solution. There is a little problem. Pool pump has its own timer. There are 4 hot wire for 240v. WH 40 is a dpst with 4 contacts. For example: power from breaker goes where? There are 2 240v 40amp contactors between Power Supply and Timer.So how to send power to thermostats when timer is ON? I really appreciate if you try to guide me in writing instead of a diagram.

  • dpetroni2006 Apr 01, 2011

    Hi,I build a tankless hot water for pool.I need to delay power to it,mean heater ON after pool pump start.Pool pump has its own timer.I have the following parts: 2 9kw elements,2 contactors 240v 40amp.2 upper thermostats,1 WH 40 timer.Do I need more parts? There are 4 hot wire,HOW THOSE WIRE SHOULD BE CONNECTED? I prefer a writing guide on how to.Mean:how the wire from breaker should be connected to contactors,from contactors to timer, from timer to thermostat, from thermostat to elements. Tank You

  • dpetroni2006 Apr 01, 2011

    Hi HANS, pool pump HAS ITS OWN TIMER. The contactors 240v 40 amp. 2 double pole 40 amp. breakers, 4 #8avg hot wire, 1 WH 40 timer, 2 upper thermostats. THE POOL PUMP IS NOT IN A PICTURE. Power is 240v. Contactors are double pole also.

  • dpetroni2006 Apr 01, 2011

    Hans, I do have a tankless electric heater, made by ECOSMART - ECO18POOL. NOT happy with it.Specifications are: 240v 18 kw 75 amp. Is 2.5 amp per circuit too little for safety? Where the contactors should be placed before or after timer. So after all I do need 2 timers.Right? Tank you

  • dpetroni2006 Apr 04, 2011

    Hi Hans, tank you for your desire to answer to my question. Is there a explanation to: INSTALL A 40amp CONTACTOR AND CUT ONE LEG OF 240v TO EACH ELEMENT. WHAT THAT IS MEAN?

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The WH 40 is a double throw switch, meaning that it will switch two contacts simultaneously. If you are switching the pool pumps with this WH 40 they will all switch at the same time without the desired delay. (You do not mention how the pumps are switched).
To connect the timer for the elements, a live and a neutral are needed to run the clock.
A live is connected to the two switched 'in' terminals and two wires must then be run to each of the coils on each of the two relays.. A separate live must go to each pole of each relay, the switched live then goes through the thermostats and to the elements.
A neutral must also go straight to the neutral side of each relay coil and to each element, unless you are using double pole relays, in which case you can switch both the neutral and the live wires going to the relays (this is the preferred circuit). Then each switched live will go to a thermostat and the switched neutral will go the other terminal of the heater element. The elements you are using are very heavy and your relays will have to be able to handle around 120 amps at 110 volts or about 60 amps at 220 volts. At 220 volts your 40 amp contactors will only handle 8.8 kw with no safety margin.
If you want a safety feature to time the pumps and elements separately, you will either need two timers or perhaps a pressure switch or flow switch to isolate the heaters when the pump pressure or flow falls.
Come back to me if this layout does not agree with what you have in mind or I have not made any point clear enough.

Posted on Apr 01, 2011

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  • Hans Pearson
    Hans Pearson Apr 01, 2011

    At 240 volts you are operating right at the limit of the contactors - no safety margin at all. Are the instructions clear, forgetting the last two paragraphs because the wiring would still be the same. The timer switches the relay, the relay switches on the power to the thermostat and the thermostat switches the elements according to the preset temperatures. Come back to me if you need any more information. Hans.

  • Hans Pearson
    Hans Pearson Apr 01, 2011

    One switch will operate the two contactors, they draw an amp or two ant most. Personally I feel you need to work on a 50% safety margin to be on the safe side, considering that you will probably have a surge on start-up and arcing at shutdown. Also, power surges will increase the amperage being drawn during the surge. The timer should operate the contactors - actually relays - the timers are only rated at 40 amps. per contact.

  • Hans Pearson
    Hans Pearson Apr 02, 2011

    I have spoken to an electrical engineer and he thinks that your 40 amp contactors will handle the 9 kw elements barring any unforeseen eventualities. Come back to me if you would like to discuss an alternative to the time switch for the elements. Hans.

  • Hans Pearson
    Hans Pearson Apr 03, 2011

    I discussed your problem with another electrical friend and he feels that the 40 amps will work, but will be on the borderline. He also brought up was a protection system that will cut out your heaters in the event of a pump failure. Either a pressure switch or a flow switch in the line that will sense a lack of water movement and will trip out the heater contactors as I mentioned in my post above.

  • Hans Pearson
    Hans Pearson Apr 04, 2011

    What that means is that you can operate the two elements from one contactor seeing that they are DPST. Each contact can handle 40 amps so you take one live lead to one terminal and one to the other and the two outlet terminals will go to one element each. Two consolations are that when switching an element on or off it will switch with very little surge in current and with time the resistance in the elements will increase, reducing the current to a more acceptable level for the contactors. Hope that makes sense. As for answering your questions, I am enjoying working this system out with you. We must just not forget the no-flow protection for the elements. Looking forward to hearing from you again.

  • Hans Pearson
    Hans Pearson Apr 06, 2011

    Have not heard from you for a while, how are you doing on the project. Hans.

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The use of the WH40 timer is NOT appropriate for sequencing the pump and heater as you have described. If these timings are really critical you ALSO need to consider sequencing in the event of power failure. You would not be able to extend the pump running without power and when power is restored you have to have a timer that will reset to the desired sequence.
I will suggest a simpler method to consider. Use a flow switch to activate the heater. In fact a simpler pressure switch on the high side of the pump could turn on the relays to activate the heaters. This would be much simpler that trying to sequence based on run time AND also offer the safety feature should the pump fail or become weak. Just connect the pressure switch to gate power to the thermostats which in turn go to the relay coils which control the power to the heaters.

Posted on Apr 04, 2011

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HI, HOW TO CONNECT 2 - silverdragon_9.gif
OK this is a pretty rough circuit.
basically, we come in on the phase to the main circuit , here we have a Fuse or Circuit breaker, through the fuse or CB, then to the, main switch, on to the Timers contacts, Normally Open, (You may NOT wish to use a set of contacts here, if so simply eliminate them)then onto the contacts of the Thermostat, Normally Closed, then to the "Hot" side of the Element, the other "Cold" side of the Element connects to neutral, and thus completes the circuit. The other set of contacts from the Timer, (You may choose to use only ONE set of contacts, as related prior?) this then, goes to the "Hot" side of the Pump Motor, with of course the Cold side going to neutral or return.
Make sure you correctly connect the Supply Power to the Timer and Thermostat's Power IN, this is to be connected at the COLD side of the Main ON/OFF Switch for the Phase wire IN.

Posted on Apr 01, 2011

  • electronic & computer repair&  servicre







    OK here is a 2nd try A little different.. You may not need two of every thing as say one contactor could do it all, and simply wire the contactor in the Timer circuit, omitted in above, so when timer times out, the contacts close and power goes through to the Element/Thermostat part....

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1 Answer

Hi how to connect one 20amps contactor and a delay timer


Which delay timer do you have? 9 pin, 11 pin, etc?
What voltage are you using?
What is amp rating on timer?

Copy following links for general and specific wiring diagrams:
http://waterheatertimer.org/How-to-wire-pin-timers.html
http://waterheatertimer.org/images/10-pin-wiring2-1000.jpg
http://waterheatertimer.org/images/ON-delay-timer-diagram-900.jpg

Add a comment.
Gene
hh

Aug 20, 2013 | Intermatic WH40 - Water Heater Time Switch...

1 Answer

How many kilowatts should a hot water tank pull or use when heating up?


some heaters have two 4500 heating elements thats 9000 watts or 9kw,s which would need 240 volts at 30 amps.breaker.

Feb 21, 2012 | Water Heaters

1 Answer

The black wire on the inside panel sparks


You posted 2 questions.
Add a comment to clarify problem
One question says black wire is sparking is inside water heater, and this question says black wire is sparking inside the panel and is posted under WH40 water heater timer.

If wire is sparking, then it is not attached firmly, or wire is not attached correctly, or there may be too many amps drawn across the terminal.
WH40 has 40 amp terminals and will handle all residential water heaters.

Open following links for instruction how to avoid sparking, and avoid fires inside timer:
http://waterheatertimer.org/How-to-troubleshoot-Intermatic-timer.html#fire
Open following link to see how to apply wire nut:
http://waterheatertimer.org/How-to-twist-electric-wire.html

Oct 08, 2011 | Intermatic WH40 - Water Heater Time Switch...

2 Answers

How can I wire a WH40 timer to a tankless water heater with 2 9kw elements? 240v 75amp 18kw. I do have # 8 AVG wire and 2 double breakers 40amp each. Tank you


You probably could but my question would be "why?" Water heater timers are made to turn power off to waterheaters during the times that we dont need hot water, like in the middle of the night or while you are at work. This keeps the hot water heater from working during those times and wasting energy (gas or electric). Tankless water heaters already have this builtin because they only work when you actuallty turn on the hot water. If the hot water faucet is not turned on, the tankless heater never comes on. It does not use a bit of energy until the hot water is actually turned on. So it will not be using energy during the night or while you are at work. So there really is no reason to do what you are thinking about unless you have another reason that I cant think of. Tankless heaters are great and this is why they save 60% of energy of conventional tank heaters.

Mar 27, 2011 | Intermatic WH40 - Water Heater Time Switch...

1 Answer

My WH40 makes a loud hum, but it works well. It is about 20 years old, and didn't make this noise until fairly recently. Could the motor be requiring replacing?


1) Yes, the noise is from clock motor turning the gears.
When timer is new, parts have a bit of white grease on them.
Turn off power and spray WD 40 or apply some white grease and see if that helps.

2) Yes
WG1573 240Volt clock motor is going bad.
Tip out mechanism using thumb spring located top inside box and check clock motor number.

Buy
WG1573 240Volt clock motor and extra trippers from Granger number 1PNK2
http://www.grainger.com/Grainger/timer-accessories/timers/electrical/ecatalog/N-8hi

http://waterheatertimer.org/How-to-wire-WH40.html

Notice on image below, there is a bit of white grease on lever.
This photo is from new WH40.
geno_3245_290.jpg

Feb 22, 2011 | Intermatic WH40 - Water Heater Time Switch...

1 Answer

Timer will not turn water heater ON at set time, has to be done manually. However, it will turn water heater OFF at set time.


If this is new installation, check wiring. Hot and Load wires might be reversed.
Check that ON OFF trippers are both attached to yellow dial.
http://waterheatertimer.org/How-to-wire-WH40.html

If timer worked fine before, and started missing recently, then tripper pins probably worn out.
Trippers contact mechanical lever, and push lever on-and-off.
Trippers are softer metal and designed to wear out before lever.
If lever is worn out, timer needs to be replaced, but try new trippers first.
Buy trippers at Grainger
http://www.grainger.com/Grainger/INTERMATIC-Timer-Tripper-2E054?Pid=search
http://www.grainger.com/Grainger/timer-accessories/timers/electrical/ecatalog/N-8hi

How WH40 timer works:
Clock motor rotates dial.
ON-OFF trippers on dial contact lever.
ON tripper pushes lever one direction.
OFF tripper pushes lever other direction.
Lever moves electrical contacts together, or pulls contacts apart.
When lever moves on-and-off, manual override lever also snaps back and forth with audible clicking sound.

Using q-tip, add touch of white grease to lever where trippers contact.

geno_3245_110.jpg

Nov 25, 2010 | Intermatic WH40 - Water Heater Time Switch...

1 Answer

New Intermatic WH40 electric water heater timer for solar


make sure your line wire is on the correct connection seems to be connected to the off going contact. then the clockmotor runs only if timer is switched on. to be sur there is a diagram on electricsuppliesonline.com, search/shop by brand, intermatic. good luck

Dec 27, 2009 | Intermatic WH40 - Water Heater Time Switch...

1 Answer

Clock on Intermatic WH40 Timer Switch does not rotate


Timers are a waste of time . I would disconnect it and get rid of it. Water heaters nowadays are so energy efficient and the thermostats take care of when it heats and shuts off. Your timer might save you pennies a year!

Feb 27, 2009 | Intermatic WH40 - Water Heater Time Switch...

1 Answer

No constant hot water...


Only two things come to mind. Either the clock is not set to the correct time (which I'm sure it is) or one of the elements most likely the bottom one is not heating for some reason. I would start by leaving the heater on 24 hrs by removing the trippers and switching it on. See if the problem goes away. If it does then focus on the timer settings, give it more warm up time etc. Make sure the clock is set to the right time and keeps time. If the problem persists on a 24 hrs running schedule then focus on the elements. --Turn the power off at the breaker-- and remove the access cover for each of the elements and or thermostats. Check the thermostat settings on each element for reasonableness. Sometimes the thermostat is covered by insulation material. If you need further assistance please write back with more detail. I can walk you through an element checkout if you have an AC volt / ohmmeter but since its new it should been under warranty.

Jan 19, 2009 | Intermatic WH40 - Water Heater Time Switch...

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