Using Heater with Variable Speed Pump

[mattide]

Hi All!

I need help with controlling my heater. I am upgrading my single speed Hayward 1 1/2 HP Super pump to variable speed 1 1/2 HP Pentair 342001 VS Superflo and I need it to work with my Pentair Maxtemp 400 heater and I can't figure it out. Currently I have an Intermatic manual timer that controls the pump and heater, on the same circuit. There is a fireman switch connected from the Intermatic timer so that the heater (if on) will turn off approximately 10 minutes before the hayward pump turns off (I guess it prevents damage and is recommended in the manual). The new Pentair pump has it's own timer built in and I want to use that, since if I use an external timer with the Pentair it will only operate at a single speed whatever it was at when it last turned off and this defeats the purpose of a variable speed pump.

Also, the heater does have a flow sensor, so the heater would turn off when the pump shuts off, however I'm guessing leaving hot water in the heater may cause damage and having 10 minutes of cooler water run through it cools it down. But I searched the forums hear and on Google and I could not find a single instance of damage occuring because the heater was shut down at the same time as the pump.

I guess I could have a separate timer for the heater, and make sure it is only operating while the Pentair pump is on, but this seems kludgy and the timers could get out of sync.

Questions:

1. Is it really that important to turn off the heater 10 minutes before the pump?

2. Other than an external control system (they are so expensive and I don't really want one) how can I hook this up so that the heater will turns off about 10 minutes before Pentair variable speed pump turns off?

3. Other than the super expensive Pentair automation controller, is there an inexpensive controller that will allow me to control the variable speed Pentair and also close the fireman switch 10 minutes or so before the pump turns off?

Thanks, Matt

 

[Spa Owner]

Questions:

1. Is it really that important to turn off the heater 10 minutes before the pump?

2. Other than an external control system (they are so expensive and I don't really want one) how can I hook this up so that the heater will turns off about 10 minutes before Pentair variable speed pump turns off?

1: Yes. If the heater is running full at time of shut down a loss of flow can cause the hot water in the heater to flow out to the pipe works connecting the heater and this can cause the pipe works to fail. This is why they are asking to run for 10 minutes with no heat.

2: I doubt there is any provision for this. I think external is likely the only way.

 

[mattide]

1: Yes. If the heater is running full at time of shut down a loss of flow can cause the hot water in the heater to flow out to the pipe works connecting the heater and this can cause the pipe works to fail. This is why they are asking to run for 10 minutes with no heat.

2: I doubt there is any provision for this. I think external is likely the only way.

Bummer, OK. I don't run the heater all that often, just a few hours before we are going to use it in the shoulder season (am in NH). I did find this controller which looks like it will work but it's still over $500 and gets mixed reviews: https://www.amazon.com/Intermatic-PE653RC-Wireless-Variable-Two-Speed/dp/B0042D4RQ4/.

Short of a controller I guess having a secondary timer just for the heater will work, just have to make sure that it turns off the heater before the pump is scheduled to turn off, and since they are independent from each other there is some risk they get out of sync somehow, so it's not foolproof.

 

[Spa Owner]

Short of a controller I guess having a secondary timer just for the heater will work, just have to make sure that it turns off the heater before the pump is scheduled to turn off, and since they are independent from each other there is some risk they get out of sync somehow, so it's not foolproof.

Timer out of sync risk not much if you check or reset it each time you start to use the heater and if there are power outages.
Damage to pipe work risk only a few metres of pipe and maybe a threaded socket (whatever you call them there) cost to repair minimal.
Loosing water and subsequent damage possible risk if the timer fails and the pipe is damaged and not inspected and not realised probably reduced to manageable.

 

[mattide]

I ended up getting the Intermatic PE653RC for about $400 which controls variable speed pumps, heaters, swg's, etc. PE653RC - Intermatic
. Apparently it's a little quirky to program but it is by far the least expensive pool control system out there.