Case study to determine root cause of Pentair mastertemp 400 not igniting

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Asherk74

Well-known member
Jun 9, 2021
79
Agoura Hills
Pool Size
17500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
The history:
-Last summer, we bought house and upgraded to new pool heater, Pentair Mastertemp 400
-after installation, we cannot get ignition; Pentair rep comes out, says not enough gas flow
-Gas company comes out, upgrades meter to 400k btu (max), 'listens' to amount of gas flow at heater, says not enough but static pressure is good
-installer says the underground pipe is to small (about 100 foot run), quotes me 4k to run new pipe, I pass and accept no heater for the season
-Now to this season, I rented an underground pipe locator (so cool!) and marked out the gas run and found a nice diggable spot about 25 feet from heater.
-I finally find the gas pipe and it measures 2" !, it is of the yellow polyethelene type, so should be nice and intact.

I just called the gas company to do another check, perhaps upgrade the meter again or up regulator?
Kind of lost at where to go next. I can get a Pentair rep to come back as I am still under warranty?
could there be some blockage in the pipe (how would I test for this/clean it)...
Any input would be appreciated as we spent over 3K on a heater we have never used!!!
 
A 2” buried line at 100ft distance is more than enough. You need to get a qualified gas plumber to come out and do more than “listen” to the flow 🙄. The internal gas valve has test ports on it and the manual has a test procedure for measuring both the static pressure and the dynamic pressure when a call for gas is made by the heater. If the pressures at the valve are good, then the problem is with something else and likely at the Fenwal ignition module. There are also known grounding issues that can occur but the heater will typically ignite and then shut off with those kinds of problems.
 
Post pics of your gas meter, pipes out of the gas meter, and heater showing gas pipes into it.
 
Asherk74 said:
The pentair rep last year used a manometer and found the dynamic pressure drop to be below range..
Click to expand...

Can the gas company come out and make sure their meter and regulator are working. Regulators can fail.

Are there any other gas appliances on that line?
 
JamesW said:
How low did it drop?

What were the readings for static and dynamic?
Click to expand...
I do not recall, I am thinking of buying a cheap manometer to test.
I have a gas company guy scheduled to come on Tuesday.
I just started it up again and here is how the 'cycle goes'

At startup, quick flash of ERR AFS (fleshes twice, then does not reappear); red heating light goes on and I hear a click and then the smell of gas of sorts; after about 10 seconds, heating light begins to flash, smell dissipates and 'tries again in 30 seconds. this goes on for 3 minutes and then it 'gives up' while flashing ERR IGN.
 
What is the supply voltage and what voltage is the heater set to?

Do not switch to the 120 plug unless you are 100% sure that the supply voltage is 120.

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Brand New Pentair MasterTEmp 250 wont fire up

Help. We replaced our previously blow Pentair MasterTemp 250 with the exact same model, thought 5 years newer, same plumbing same position everything and when we set it up exactly as is out of the box, it wont kick on. We have put a manometer to the test port on the outsdie the heater and...
www.troublefreepool.com www.troublefreepool.com
 

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What other gas appliances do you have in the house?

Your gas meter is 400 cfm which is barely adequate to run the heater with no headroom for any other gas appliances running at the same time.
 
A few thoughts. I used to have the Sta-Rite version of this heater (the Pentair version is the same heater, just in a rectangular metal box). It worked well for a couple of seasons, and then started eating ignitors. Has a technician checked the ignitor?

ERR AFS is the air-flow switch...basically means that the air intake or exhaust could be restricted. If the error clears within 60 seconds, the heater will continue. But you might want to check--one issue I had with this heater is that it was extremely susceptible to rodent habitation & they would get into the insulation and everywhere.

ERR IGN is the ignition control module. This can only be cleared by power cycle, and is exactly what I would get when my ignitor was faulty.

As for the gas supply:
When I changed heaters and added a NG grill to the same run, the plumbers had the gas company come and swap my regular meter for a medium-pressure meter that is denoted as such by a red face where the dials are. Then, they added regulators at the house, pool heater, and grill. So it runs medium pressure (which can deliver much more flow through the same pipe) up to essentially the point of use, and gets regulated down.

They should be able to use a manometer to check, and adjust the regulator as necessary.
 
JoyfulNoise said:
Can the gas company come out and make sure their meter and regulator are working. Regulators can fail.

Are there any other gas appliances on that line?
Click to expand...
Gas rep coming Tuesday. I do not think the BBQ is spliced in
JamesW said:
View attachment 412961
The below pipe is 3/4" as shown on the valve.

The outside diameter is not the pipe size.

View attachment 412962
Click to expand...
ah ok, so the main run Inner diameter is probably 1.5” and then close to the heater , hopefully the final elbow drops down to 0.75” ID
 
JamesW said:
Possibly due to low fan speed due to having the wrong voltage as shown in the other thread.

Click to expand...
I do not know as a fact what the input voltage is (can I safely test with multimeter?) if it helps, the same power source is also going to Aquarite SWG and Pentair Intelliflo pump
 
ajw22 said:
What other gas appliances do you have in the house?

Your gas meter is 400 cfm which is barely adequate to run the heater with no headroom for any other gas appliances running at the same time.
Click to expand...
Ya… hot water heater and stove/oven are the only other draws; I’m hoping they will size up my meter Tuesday
 
jedigrover said:
A few thoughts. I used to have the Sta-Rite version of this heater (the Pentair version is the same heater, just in a rectangular metal box). It worked well for a couple of seasons, and then started eating ignitors. Has a technician checked the ignitor?

ERR AFS is the air-flow switch...basically means that the air intake or exhaust could be restricted. If the error clears within 60 seconds, the heater will continue. But you might want to check--one issue I had with this heater is that it was extremely susceptible to rodent habitation & they would get into the insulation and everywhere.

ERR IGN is the ignition control module. This can only be cleared by power cycle, and is exactly what I would get when my ignitor was faulty.

As for the gas supply:
When I changed heaters and added a NG grill to the same run, the plumbers had the gas company come and swap my regular meter for a medium-pressure meter that is denoted as such by a red face where the dials are. Then, they added regulators at the house, pool heater, and grill. So it runs medium pressure (which can deliver much more flow through the same pipe) up to essentially the point of use, and gets regulated down.

They should be able to use a manometer to check, and adjust the regulator as necessary.
Click to expand...
That would be great! Having a stand alone regulator for the pool and house but not sure on their rules
 
Asherk74 said:
I do not know as a fact what the input voltage is (can I safely test with multimeter?) if it helps, the same power source is also going to Aquarite SWG and Pentair Intelliflo pump
Click to expand...
The Intelliflo takes 240 volts.

Where exactly does the heater get its power from?

Is there a separate breaker or switch?

You can test it if you are comfortable doing that.
 
The yellow tubing might be 1.25" or 1.5"

If it's 1.25", it is a little bit undersized, you need to know the exact pipe sizes for all pipe and the length of each pipe.

It also depends on the static pressure coming out of the meter and what the dynamic pressure is while operating.

If necessary, you can change to 2 psi near the house meter and then drop down to 8" wc near the heater with a regulator to avoid a replumb.

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