Pentair Master Temp 400

Please post current pics of the way your valves are now set. I went through your plumbing with you in another thread. You have complex plumbing and one valve misset can create your problem.

Your heater only works with the black pump. You need to have the valves set to pull water only from the spa and return only to the spa using the black pump to get good heat to it.

Lets go back and review the position of each of your valves as we discussed here Spa Losing Water when Pump is off overnight

Album — Postimage.org here is how the valves are set


What gets me is that at one time - the way the valves are set now - it actually worked. It stopped working after successfully heating the spa
 
Let's refer back to the valve numbering of this pic.

2KDKY.jpg

It does not look like you changed the valve positions to heat your spa only. The valves are set to heat both your pool and spa. That spreads the effectiveness of your heater over a large amount of water.

If you want to heat only the spa you turn valve 2 180 degrees from where it is now. That opens spa suction and blocks pool suction and draws all water from the spa. You must also move valve 5 the handle 90 degrees up to block the TO POOL pipe and send all water to the spa. Return the two valves to their prior position to restore flow to the pool.

The duck bill side of the valve opposite the handle is the part that blocks a pipe. Make sure you never block the water flow pipe into the valve when you are moving the valves. I recommend you turn off the pump anytime you move valves.
 
I marked in blue the way the valves need to be moved to heat the spa only.

2KDKY.jpg
 
Let's refer back to the valve numbering of this pic.

View attachment 86458

It does not look like you changed the valve positions to heat your spa only. The valves are set to heat both your pool and spa. That spreads the effectiveness of your heater over a large amount of water.

If you want to heat only the spa you turn valve 2 180 degrees from where it is now. That opens spa suction and blocks pool suction and draws all water from the spa. You must also move valve 5 the handle 90 degrees up to block the TO POOL pipe and send all water to the spa. Return the two valves to their prior position to restore flow to the pool.

The duck bill side of the valve opposite the handle is the part that blocks a pipe. Make sure you never block the water flow pipe into the valve when you are moving the valves. I recommend you turn off the pump anytime you move valves.

going to try this now - my question is...why would it work for 3-4 hours with this valve setup and then all of a sudden stop working?
 
i got an invalid link on your attachment

Fixed it above.

- - - Updated - - -

going to try this now - my question is...why would it work for 3-4 hours with this valve setup and then all of a sudden stop working?

Not being there with you I can't answer that. I just know what I see now with your valves.

Please turn off your pump before you move any valves.
 
Are the valves set so that you are getting water only from the spa and returning only to the spa?

Does the heater continue to run with no errors?

Is the heater running continuously but the temperature of the water is not going up even after 15 minutes?

Do you have a water temperature thermometer in the spa?

Does the heater temperature readout match the actual temperature of the water?

Are you trying to run the spa jet pump at the same time?

The way that the spa jet pump is plumbed is not good. If it runs at the same time as the filtration pump, it will block most of the flow coming from the heater.

That could cause the heater to run with improper flow.

You really can't use the jet pump like it is when you're trying to use the filter pump.

With the heater running (with the valves in place as in the original picture) the water temp is 84* which is warmer than it is in the pool (its not that warm up here)

That's why I'm thinking it's not a valve issue, but a heater issue - it seems as if it's not heating the water up to a correct temp
 
It looks like you have the spa suction closed and the return going to pool and spa. See this video for the operation of a jandy valve. Note the off letters on the handle.

How a Jandy 3-Way Valve Works - YouTube

which makes sense - because when I moved that spa suction handle, all the water out of the spa drained.

made the adjustments and my pump doesn't want to stay on - seems like a pressure problem now. I'm at a loss here.
 

Enjoying this content?

Support TFP with a donation.

Give Support
the spa is not low on water

is the return valve #5? if so, yes that was set to spa only (off position was on "to pool" side of pipe)

The setup worked great last Saturday with how it was pictured originally - the water just stopped coming out hot after a few hours of use.

I don't know much about this but I think the valves were set in the right position because when i was heating with the valves as they were the spa was getting hot water and the pool wasn't getting any (which is how i think it should be)

- - - Updated - - -

It looks like you have the spa suction closed and the return going to pool and spa. See this video for the operation of a jandy valve. Note the off letters on the handle.

How a Jandy 3-Way Valve Works - YouTube


how hot should the exhaust temp be? It's like it just stopped burning as hot - the water that comes out comes out warm...just not hot (like it did when i started it on saturday)
 
which makes sense - because when I moved that spa suction handle, all the water out of the spa drained.

made the adjustments and my pump doesn't want to stay on - seems like a pressure problem now. I'm at a loss here.

I think you have a problem with valve 5 or the check valve in your spa return circuit.

The blue arrows show the way your spa suction flow is. That is working and is draining your spa.

If the water is not returning to the spa then it must be returning to the pool. That is controlled by valve 5. You need to open valve 5 and see if the diverter is broken or not closing completely. And you should examine the check valve and see that the flapper and spring are operating properly.

The yellow arrows show the way your spa return water should flow back to the spa.

2KDKY.jpg
 
You have a temperature probe in the return water line. Someplace that should be displaying and showing you that the temperature rises when the heater is on. I indicated in blue the temp probe in your plumbing.

2KDKYa.jpg

- - - Updated - - -

Post pics of the way your valves are when the spa is draining.
 
You have a temperature probe in the return water line. Someplace that should be displaying and showing you that the temperature rises when the heater is on. I indicated in blue the temp probe in your plumbing.

View attachment 86463

- - - Updated - - -

Post pics of the way your valves are when the spa is draining.

James is right- that's not a sensor - it's a hose with water going through - no electrical connection and no sensor in it either.

- - - Updated - - -

How how should the heater exhaust get? is it possible it's just not burning that hot?
 
290 to 350 is the acceptable range for the stack flue temperature.

The hd model can run up to 75 degrees hotter. So, the 400 hd maximum temperature should be 425.

The shutdown temperature is 480 to 500 Fahrenheit.

If the heater is running continuously with no errors, I think that it's probably ok.

I suspect that the issue is a valve configuration.
 
290 to 350 is the acceptable range for the stack flue temperature.

The hd model can run up to 75 degrees hotter. So, the 400 hd maximum temperature should be 425.

The shutdown temperature is 480 to 500 Fahrenheit.

If the heater is running continuously with no errors, I think that it's probably ok.

I suspect that the issue is a valve configuration.

I have a 400, not a 400hd. so maybe it is a valve issue.

I'll try and adjust some more.

thanks
henry

- - - Updated - - -

290 to 350 is the acceptable range for the stack flue temperature.

The hd model can run up to 75 degrees hotter. So, the 400 hd maximum temperature should be 425.

The shutdown temperature is 480 to 500 Fahrenheit.

If the heater is running continuously with no errors, I think that it's probably ok.

I suspect that the issue is a valve configuration.

although when its running (and hot) the "heater" light is not on. Not sure why - was thinking maybe the led could be out?
 
Be careful, if you run with no flow, you can damage the heater.

When running and heating, the heating light should be on.

Maybe post a video on YouTube and link so that we can see what's happening.
 
Also, when I was heating the pool on Saturday - the jets in the pool were OFF but yet the spa was being heated and the spa was overflowing into the pool as it normally does.

Is there a way to heat just the spa and make sure water doesn't overflow into the pool?
 

Enjoying this content?

Support TFP with a donation.

Give Support
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.