Intermatic Dual Timer and Spa Heater

[david_]

I recently removed my booster pump as I use a robot. Now the 2nd intermatic timer swtich has nothing on it. I also recently had a Jandy JXI400P installed.

Would it make sense to wire the heater to the 2nd switch (right now it's on the main/pump timer) so I can control them separately?

When I go to VSP in the coming months, I'll probably get rid of the timer box and just have 2 toggle switches instead. Thanks!



Thanks!

 

[ajw22]

Would it make sense to wire the heater to the 2nd switch (right now it's on the main/pump timer) so I can control them separately?

The problem with having your heater on a separate timer is if the two timers get out of synch your heater can be powered on when your pump is not running. While the heater has a pressure switch that should prevent the heater from running when the pump is off there can be pressure in the system and the heater can run. That will damage the heater and pipes.

You can wire the Intermatic timers around problem. For that you need to:

• Power the heater timer clock power from the pump LINE side
• Connect the heater timer LINE to the pump timer LOAD

That lets the heater timer clock run even when it has no LINE power. And even if the heater timer clicks on the heater will only get power if the pump power is on.

 

[david_]

The problem with having your heater on a separate timer is if the two timers get out of synch your heater can be powered on when your pump is not running. While the heater has a pressure switch that should prevent the heater from running when the pump is off there can be pressure in the system and the heater can run. That will damage the heater and pipes.

You can wire the Intermatic timers around problem. For that you need to:

• Power the heater timer clock power from the pump LINE side
• Connect the heater timer LINE to the pump timer LOAD

That lets the heater timer clock run even when it has no LINE power. And even if the heater timer clicks on the heater will only get power if the pump power is on.

Perfect. Clocks both already have line power all the time (as long as breaker and emergency switch are on). And 2nd timer already only powers when 1st on is (booster setup). I'll just move the heater power over to the 2nd timer:

 

[1poolman1]

I recently removed my booster pump as I use a robot. Now the 2nd intermatic timer swtich has nothing on it. I also recently had a Jandy JXI400P installed.

Would it make sense to wire the heater to the 2nd switch (right now it's on the main/pump timer) so I can control them separately?

When I go to VSP in the coming months, I'll probably get rid of the timer box and just have 2 toggle switches instead. Thanks!

View attachment 467562

Thanks!

Wire the heater directly and use the on/off control on the heater. No need to make it complicated unless there are specific times you absolutely do not want the heater to run. It won't come on with the pump not running and with a VSP it will need the RPM to be high enough to close the pressure switch. They are very reliable.

 

[JamesW]

You should install a flow switch with the heater.

The pressure switch can be activated even when the valves are closed.

 

[JamesW]

You can install a fireman's switch (red dot) to turn the heater off a few minutes before the pump turns off to allow a cooldown.

You should not shut off power to the heater while it is running.

https://www.intermatic.com/Product/156T4042A

 

[JamesW]

You should have a check valve at the heater outlet and not a three way valve.

The way you have it now can trap pressure in the heater and if the heater runs, it can explode when the water boils.

 

[david_]

Thanks - great info.

I could get a fireman switch, but per the manual that can actually turn on the heater too(?), which is bad for my situation as I would never run it daily with my pump: "NOTE: When a fireman’s switch is being utilized and “hi-lo-com” is selected, the heater will fire automatically when the contacts close even if the user interface on the heater is off."
Edit: I wouldn't use hi-lo-com, I would use Remote TSTAT mode. Still, I don't think I'll be controlling this via timer. Given we're using this for occasional hot tub, I imagine I'll be shutting it all down myself. My steps would be:

1. Turn off heater via heater interface
2. Turn off pump 15 mins later.
3. (Optional) Turn off power to heater.
4. (Optional) Bypass heater and open drain.

Regarding the 3-way valves - I see the potential issue. The problem is it's not the only place the return can be completely blocked. I think a safer alternative is to install a pressure relief valve as outlined on page 24 on the heater body. I just need to see if 50 PSI would cause any issues for the rest of my system (I would think not given my filter gauge never goes about 30 in spa mode).

Noted on powering off unit if it's running - manual states it needs time to run the blower after heat is turned off.

 

[JamesW]

You would not set it to hi-lo-com.

You would just use the remote thermostat mode to shut off the heater.

You would still set the heater to the correct set point so that the heater will work based on its own thermostat.

If you turn the heater off, the remote will not override the heater setting.

I highly recommend a flow switch because any misconfiguration can severely damage the heater even with a pressure relief valve.

 

[JamesW]

 

[david_]

I highly recommend a flow switch because any misconfiguration can severely damage the heater even with a pressure relief valve.

Works for me. Seems easier too. I can't find ones specifically for heaters, but would this work?

Aftermarket Flow Switch for Pentair® IntelliChlor® Salt Systems

Water needs to flow through a salt system properly in order for chlorine to enter your pool and keep it healthy and clean. When your Intellichlor® salt system starts to read No Flow when there is clearly water flow, or if it is sensing water flow when your pump is off, its probably time to...

poolguysupply.com

 

[JamesW]

The SWG flow switches are calibrated for about 15 GPM and your heater needs 40 GPM.

It's better than nothing because it will at least ensure that there is some flow.

The biggest risk is zero flow especially if the lines are blocked.

You mount the T and the sensor in the plumbing going into or out of the heater and put the flow switch wiring in series with the pressure switch or instead of the flow switch.

https://www.amazon.com/dp/B097CYD8J4/

This is for heaters, but it is more expensive.

Raypak Flow Switch Kit - 007142F - INYOPools.com

Flow Switch Kit - 007142F

www.inyopools.com

Heaters Parts | Heaters | Parts & Accessories | Commercial - Hayward Pool Products

Hayward commercial pool products are supported by a full range of replacement parts and accessories for heaters. Universal H-Series gas heaters combine industry-leading hydraulics,and energy efficiency and reliability, with low-NOx emissions.

www.hayward-pool.com

UHXFSW1930 - H-Series H150-H500 Flow Switch Kit - Hayward

This is a Hayward Flow Switch Kit for the H-Series Low NOx pool heaters, models H150 to H500.

www.poolweb.com

UHXFSW1930 - H-Series H150-H500 Flow Switch Kit - Hayward

This is a Hayward Flow Switch Kit for the H-Series Low NOx pool heaters, models H150 to H500.

www.poolweb.com

I got lucky...now I need help adding a flow switch

Evening, TFP World! We have an autocover that stays closed except when the pool is in use or needs to be left open to breath. Today, it was a beautiful day, so I left it open most of the day. I did not appreciate how much Crud was coming off the trees, and allowed both skimmer baskets to get...

www.troublefreepool.com

Okay.....so I finally had the time yesterday to hook up my new Flow switch from Harwil, and it's working perfectly. Very simple - just cut a section of 2" out before the heater union (there are no requirements for straight pipe before or after the switch), installed a 2" slip x 1" NPT tee, thread the flow switch in, wire it up, and off you go. I calibrated it with a continuity tester and my FlowVis for 45GPM so it closes as the same time as the factory pressure switch. So far, it's working like a champ. I'll report back here in the event something changes.

 

[JamesW]

The Raypak and Hayward heater flow switches are made by different companies.

I think that the Raypak is the one below.

https://www.supplyhouse.com/Taco-IFS01BF-1-Brass-Flow-Switch-w-Flexible-Paddles-Single-Switch

A flow switch that is commonly used for that application is our Q-8N series flow switch.
The part number I would recommend based on plumbing size and flow rate is Q-8N/2/2/A/VITON.
This flow switch is an adjustable flow switch with an ON set point at minimum is 44 gpm and can be adjusted up to 65 gpm in a 2” pipe.
Attached is a data sheet.

The current price for the flow switch is $148.76 each.
We do have a minimum order value of $150, so either 2 units would need to be ordered or we can round up to $150.

You are welcome to purchase direct from Harwil. For purchases we accept Visa, Mastercard, and American Express.
The shipper we use is UPS, if you have an account with UPS we can use that to ship with or just add the cost to the order total.

The email to send orders to is: [email protected]

I have a residential inground pool with a Pentair MasterTemp 4000BTU heater that I installed last year. These heaters have a pressure switch to sense flow, and for a number of reasons, I’d like to replace that with an inline flow switch. The heater manual shows 45GPM for minimum flow to operate. My plan is to place a threaded in the 2” PVC line to hold the flow switch and run the leads to the control board of the heater.

Based on that application, could you suggest and provide pricing for the flow switch that would be best for that application? Thanks!

 

[JamesW]

In my opinion, it’s foolish for heater manufacturers not to include a flow switch with their heaters.

It would be simple.

Just include a T and a flow switch in the box with the heater and a supplemental instruction to wire the switch in series with the pressure switch or instead of the pressure switch.

You would not need to modify the heater at all.