SPA heater, what would happen?

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Hello,

I had contacted the local gas company (gas provider), two qualified gas plumbers and local officials who authorize gas installations in my area. It took me long time in order to get the required inspections and quotations.

In summary,
  • The local gas company will perform the modifications at the meter side, including the supply of the meter and regulators
  • The qualified gas plumber will perform the modifications at the heater side, including the installation of the regulator, valves, sediment (trap), etc... The regulator at the heater must be placed outside the service room as required by the officials
  • The pipe length is around:
    • High pressure: 68.5m (225ft)
    • Low pressure: 6.3m (20ft)
I created the following summary diagram (view attached) based on the discussions and quotations.

Based in previous experience (where the gas line was installed incorrectly), @JoyfulNoise, @JamesW, please, may you take a look to this diagram and let me know if there are something incorrect from your point of view.

Additionally, any thoughts or suggestions regarding which pressures must be set in each valve?

Thanks again!

----
References:

Untitled1.jpg
 
Hello,

Finally, the gas line was upgraded to high pressure. The new meter and regulator near of the heater were installed and all work inspected. The picture below shows a summary.

1734631245170.png

I performed the dynamic pressure test with a digital manometer, resulting in 12.41" wc static and 6.68" wc once started.

1734631939863.png

I start the heater pump (at 2000 RPM), later the heater using the device panel (not fireman's switch, instead using a jumper). After a while trying to start, the Service led turn on. During the process, I smell gas.

Hello @JoyfulNoise @JamesW any suggestion in what I must be focusing now? It seem the pressure drop is high and not sure if I will need to focus on the gas line or something else in the heater.



Thanks!
 
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The heater sediment trap is not piped correctly following Pentair's Installation Manual.

The correct sediment trap design is for the gas to make a 90 degree turn to go into the heater while the sediment can drop down into the sediment trap as shown in the Pentair diagram below.

Your sediment trap is before the 90 degree bend. The sediment will follow the gas flow, not drop into the stub it passes over, and continue into the gas valve eventually causing it to fail.

1734633527083.png

Gas_Heater_Sediment_Trap.png
 
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Hulaomr said:
After a while trying to start, the Service led turn on. During the process, I smell gas.
Click to expand...
Service System or Service Heater LED?

Service System LED usually means that the Pressure Switch is open. It's either low pressure/flow or a bad pressure switch.

If you get a "Service Heater" LED, you will have an error LED on the control board or the Fenwal of the 5 button heaters. Check the diagnostic LEDs or the Fenwal box LED for blinks.

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com www.troublefreepool.com
 
Hi @ajw22, thanks for pointing out this issue and describe the situation. I will definitely need to update this part.

I remember once the plumber finished the work, he will leave the heater un-connected from the valve because he thought I will use a gas hose (as others appliance at the house). At that moment, he finished the connection with the parts he had available and missed the point of the sediment trap.

1734634058471.png
 
ajw22 said:
Service System or Service Heater LED?

Service System LED usually means that the Pressure Switch is open. It's either low pressure/flow or a bad pressure switch.

If you get a "Service Heater" LED, you will have an error LED on the control board or the Fenwal of the 5 button heaters. Check the diagnostic LEDs or the Fenwal box LED for blinks.

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com www.troublefreepool.com
Click to expand...
The LED is Service Heater (left in the panel). The rest of the others LEDs (diagnostic) in the panel board are keep off.

In other hand, just before the Service Heater led turn on, the Fenwal LED blink three times.

The Igniter is new and tested (with a AC supply) turning red. Recently, I also tested the resistance resulting in ~80ohm.

 
What voltage is the heater connected to?

Which voltage plug - black or red - is installed in the heater?
 
Does the heater briefly ignite, producing a puff of heat before shutting down?
 

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Pressure drop is usually designed for 0.5" w.c, which indicates the pressure drop is excessive.

Your pressure drop is 5.53" w.c, which is about 11 times the design pressure drop.

However, the pressures for static and dynamic are within range and indicate that the gas is flowing.

If you have gas and a hot ignitor, you should have ignition.

Check the ignitor to see if it is getting 120 volts and using about 4 amps.

1734640524104.png

1734640447586.png
 
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Hulaomr said:
I'm not sure how could I notice that.

Please, may you suggested me what to look and where to perform the test right away.
Click to expand...
You will hear a whoosh of the heater igniting, and if you have your hand over the exhaust, you will feel a puff of heat.
 
ajw22 said:
You will hear a whoosh of the heater igniting, and if you have your hand over the exhaust, you will feel a puff of heat.
Click to expand...

Thanks for the info.

No, I feel the air with the same temperature all time during the process (from pushing "Pool on" until the "Service Heater led" turn on)
 
Is the ignitor getting 120 volts?

If no/low voltage, then the Fenwal is not providing the necessary voltage.

If the ignitor is getting 120 volts and no current/amps, then the ignitor is bad.
 
Hulaomr said:
The Fenwal must turn on the igniter a couple of seconds at least, right?
Click to expand...
1734642896808.png

SEQUENCE OF OPERATION
An electronic temperature sensing thermistor in the manifold adapter inlet controls the heater operation.

When the inlet water temperature drops below the temperature set on the operating control, the burner controller supplies power to the combustion air blower through a series of safety interlocks.

The interlocks consist of:

• the pressure switch (PS), which senses that the pump is running,

• the high limit switch (HLS), which opens if the heat exchanger outlet temperature goes above 135° F (57° C), and

• the air flow switch (AFS), which senses the pressure drop across the air metering orifice,

• the automatic gas shut-off (AGS) switch, which opens if the heat exchanger outlet temperature goes above 140° F
(60° C).

• the stack flue sensor (SFS), which shuts down the heater if the flue gas temperature reaches 480° F (249° C).

The air flow switch (AFS) senses the pressure drop across the air metering orifice.

As soon as there is sufficient air flow, the AFS closes, closing the circuit to the hot surface igniter (HSI), which ignites the fuel mixture.

On a call for heat, the blower and HSI are energized.

In about 20 seconds, the gas valve opens and ignition occurs.

The HSI then switches to a sensing mode and monitors the flame.

The heater is equipped with a digital operating control that enables the user to pre-set the desired pool and spa water temperatures.

The control enables the user to select between pool and spa heating, and features a digital display that indicates the water temperature and heater set point.
 
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