Pentair Heater will not stay lit

eagle670

New member
May 2, 2017
3
EXCELSIOR SPRINGS
#1
The heater is about 12 years old. When its turned on the fan comes on and after 60 seconds I can hear the gas valve click to open, which is followed immediately by the igniter start clicking to fire, but it does not light. It will cycle like this 3 times at which time I can smell the gas and then turn off. If I clean the filter and then try the heater it will light. The filter cartridges are never very dirty and it makes me wonder if the pressure sensors are failing. I want your opinion as what components should be replaced. Thanks for the help.
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,956
FL
#2
Typically if the filter is dirty, the heater won't try to fire at all. A dirty filter prevents the correct water pressure to trip the pressure switch allowing the heater to fire. I suspect you have something else going on with the heater. I personally have never encountered an intermittent pressure switch which acts like you are saying.

Do you have a single speed pump?
 

eagle670

New member
May 2, 2017
3
EXCELSIOR SPRINGS
#3
Typically if the filter is dirty, the heater won't try to fire at all. A dirty filter prevents the correct water pressure to trip the pressure switch allowing the heater to fire. I suspect you have something else going on with the heater. I personally have never encountered an intermittent pressure switch which acts like you are saying.

Do you have a single speed pump?
Yes it is a single speed pump. Sometimes it will light when I clean the filter and other times it does not. I have also had success with it lighting, by bleeding off air in the system. I have tested the Hi temp sensors and those seem to be fine. Once the heater lights, it operates perfectly. I appreciate the help, I don't want to go through another season fighting this.
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,956
FL
#4
Temp senors would not be the thing to look at.

What type of filter do you have?

Which model Pentair do you have?
 

Pool Clown

In The Industry
Sep 5, 2008
1,821
Silicon Valley, CA
#5
Odd that the fan would come on but not fire if it was a pressure switch problem. All the safety switch(s) must be proven before the fan would start, that would include an (accurate) water temp reading cooler than set point too. My experience with a failing temp sensor has always been a false high temp reading, or an open. Neither of which would allow the fan to start. Maybe a "failing" pressure switch? or a loose connection to the switch? :scratch:

You say that if you clean the filter, that the heater will begin to work? How long will it work for, before you have to clean the filter again? Do you get a significant amount of dirt or debris off the filter when you clean it? And, how old are the filter element(s)?
 

Flying Tivo

Well-known member
Jan 24, 2017
531
Monterrey, NL, Mexico
#6
Either the igniter is not generating a spark strong enough to light the Gas or there is some contamination of the gas that wont let it light(Rare).
I would bet is the igniter, 12 years is quite a few starts, look for the part number and get an estimate.

Felipe
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,956
FL
#8
The mini max NT should be a silicon nitride ignitor. It should glow and not spark.

I still don't get what cleaning the filter has to do with the unit not lighting until you clean it. If you had an ignitor issue, it wouldn't light even if you cleaned the filter or not. The flame sensor only comes into play after the unit lights. It wouldn't be the cause of it not lighting.

But, what does cleaning the filter have to due with the heater lighting? There is still something we can't see from here and that could be the clue.