Case study to determine root cause of Pentair mastertemp 400 not igniting
- Thread starter Asherk74
- Start date
I measured about 235 volts so 240V is the factory default, unless they messed up the install, I’ll take a look under the cover
Ok, if the voltage checks out, then the gas pressure is the next thing to measure.
Do NOT switch the voltage selector plug to "just try it out" as that could cause serious damage.
Maybe post a video of the heater trying to start.
Most likely a flame current issue, which could be lack of good flame or a flame current sensing issue.
Do NOT switch the voltage selector plug to "just try it out" as that could cause serious damage.
Maybe post a video of the heater trying to start.
Most likely a flame current issue, which could be lack of good flame or a flame current sensing issue.
Are you smelling gas?
Are you getting any ignition at all?
If no ignition, then it might be a bad ignitor.
Check to see if the igniter is getting voltage or check to see if the ignitor is drawing about 5 amps.
Are you getting any ignition at all?
If no ignition, then it might be a bad ignitor.
Check to see if the igniter is getting voltage or check to see if the ignitor is drawing about 5 amps.
jedigrover
Gold Supporter
- Sep 13, 2010
- 333
- Pool Size
- 21000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
If I recall correctly, you should be able to measure 50 ohms across the igniter. If it shows open, then the igniter is broken.
Ordered a manometer from Amazon to confirm dynamic pressure loss;
Will check resistance/voltage across igniter, as well as confirm 240 Volta and get back to you all; thanks for all the inputs!!
Will check resistance/voltage across igniter, as well as confirm 240 Volta and get back to you all; thanks for all the inputs!!
As I await the monometer, I noticed something, the pipe from street is 1” OD, I assume high pressure, then at house regulator drops pressure (7” WC or so?), but then more 1” pipe to the 400k meter, which then has 2” pipe.
So, can the 1” stretch from post regulator to meter be ‘clogging’ the 2” line from seeing its full potential volume flow?
So, can the 1” stretch from post regulator to meter be ‘clogging’ the 2” line from seeing its full potential volume flow?
Attachments
Last edited:
- May 23, 2015
- 25,713
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Wow … 7” WC into the house, that’s really low. Residential NG pressure on the low side should go all the way up to 14” max. I suspect the regulator is either undersized or bad. The street pressure is 2 psi. Then the regulator takes it down to low pressure BUT the regulator also needs to be spec’d for both pressure AND FLOW. If the regulator is too restrictive then you won’t get enough gas to the heater.
Also, whoever put the gas pipe for the pool that close to regulator and then did all that piping to go around the vent was not to bright. Maybe ask the gas service tech if it’s possible to clean that installation up. Lots of unnecessary 90’s.
Also, whoever put the gas pipe for the pool that close to regulator and then did all that piping to go around the vent was not to bright. Maybe ask the gas service tech if it’s possible to clean that installation up. Lots of unnecessary 90’s.
They made all those crazy elbows to add a union and shutoff valve, I know. Brutal design…
Do you thing the pipe size out of the regulator matters?
Gas company coming Tuesday, I’m going to ask him to max out pressure/flow
- May 23, 2015
- 25,713
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
No, the pipe diameter is fine. Is just the riser connection from the meter to the underground pipe which is 2”. The majority of the connection is 2” so it’s ok if the risers neck down to 1”.
Also, so I know what to ask the gas guy, I understand the pressure part of the regulator, but how does it effect flow, as in is their an adjustment for that or just a larger regulator?
- May 23, 2015
- 25,713
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Regulators are designed to stabilize/reduce pressure from the inlet to the outlet. This is done with a set of diaphragms and internal springs to produce the correct pressure drop. That being said, the internal orifice sizes are fixed and can only allow a certain flow rate for a given pressure drop. Typically, the “larger” the regulator (as measured by its diaphragm diameter) the higher the flow rate of gas for a fixed pressure drop.
So all you need to do is make sure that the regulator and meter they install gives you the maximum allowable static pressure (according to local residential codes and whatever limitations the gas company has in place) and that it designed for a flow rate that exceeds all of the requirements of your various appliances. A 400kBTU/hr heater needs 400 cubic feet of gas per hour. Your hot water heaters are typically a lot less than that as are range tops. Even so, the meter and regulator should be spec’d to deliver all the gas you could reasonably need.
In this reference, it shows that the amount of gas that the plumbing can supply depends on the plumbing size, length, starting pressure and allowable pressure drop.
The starting pressure can be up to the maximum inlet pressure.
The allowable pressure drop can be determined by the starting pressure minus the drop as long as the result is that the dynamic pressure is still above the minimum inlet pressure.
The chart also shows that the pressure from the meter to the heater can be 2 psi as long as you use a regulator near the heater to drop the pressure to the recommended inlet pressure.
The starting pressure can be up to the maximum inlet pressure.
The allowable pressure drop can be determined by the starting pressure minus the drop as long as the result is that the dynamic pressure is still above the minimum inlet pressure.
The chart also shows that the pressure from the meter to the heater can be 2 psi as long as you use a regulator near the heater to drop the pressure to the recommended inlet pressure.
Does this mean the Max pressure out of the regulator would be 8.5”WC, maybe that a SoCal gas restriction?
Maybe they can swap this for a higher flow regulator
Attachments
8" wc should be sufficient.
Below shows that at a starting static pressure of 8" wc and a drop of 3", the capacity is 1065 CFH.
This means that if the pressure is 8" at the meter, the pressure at the heater would be at least 5" wc during operation.
As long as the static and dynamic are within the range of 4" wc min to 14" wc max, the pressure should be fine.
Also, note that the heater should have a drip leg, which your does not.
Below shows that at a starting static pressure of 8" wc and a drop of 3", the capacity is 1065 CFH.
This means that if the pressure is 8" at the meter, the pressure at the heater would be at least 5" wc during operation.
As long as the static and dynamic are within the range of 4" wc min to 14" wc max, the pressure should be fine.
Also, note that the heater should have a drip leg, which your does not.
Are you sure it’s a natural gas mastertemp? Propane orifices are smaller. It wouldn’t hurt to try and shut down all home appliances and try and fire heater.
So 8.0" can be ok;
how about flow? Im not sure how to read the specs of the regulator picture I posted
Its an S102, 3/16" Orifice, 5.5-8.5" WC range, and 1-86?
btw, thanks a ton for all your help thus far!
1-86 might be the date it was made.
Since the regulator is before the meter, it should be at least able to feed the meter the full meter rated flow.
Let's see what the static and dynamic are.
Did you confirm that the heater has 230 volt supply?
Since the regulator is before the meter, it should be at least able to feed the meter the full meter rated flow.
Let's see what the static and dynamic are.
Did you confirm that the heater has 230 volt supply?