Is this a gas valve problem?

[Kelly Gordon]

Hi all:

We have a Raypak heater. It's old; I don't remember its exact age off the top of my head. Last year, it worked sporadically. At first, we thought the pressure switch was the issue. But we replaced it, and the heater continue to fire intermittently.

We've been told we need a new gas valve, which is a hefty priced part. But here's the thing: over the weekend, my husband went out, turned on the gas, lit the pilot and turned the interior knob back to on and the burners lit. We hadn't yet turned the switch on the outside of the unit to on, nor had we messed with the thermostat dial. So we let it run for 24 hours, which got our pool to a decent 82, and then turned it off again. Does that sound like a gas value issue to you? Last year, it seemed we couldn't get the burners to fire, even after the pilot was lit. But yesterday, they fired just fine. But the switch to turn the unit on wasn't on? What does that mean?

We are trying to determine if we want to sink $500 into this workhorse, or if our weekend findings point to something other than the gas valve, or if we should just start saving our pennies for a new heater.

Thanks,

Kelly

 

[Pool Clown]

Something is up with that 2 dollar switch at least. Replace that, then re-assess.

500.00 for a gas valve?

I charge around 340.00 for that gas valve... And i'm expensive!

 

[danpik]

Gas valves are rarely the culprit. There were some "better idea" honeywells out there years back that were a problem, but for the most part most are pretty dependable. We need to determine if you have a milivolt system or a 24 volt system. If you have a millivolt system, you will have a powerpile that the pilot light flame heats up. It will look like this....



It will have two wires that connect to the gas valve.

If you have a 24 volt system there will be wires connected to the gas valve as well but, they will go back to a transformer. It will also have a thermocouple in the pilot flame that looks like this...



If you have a millivolt system, you will need to go thru the safety circuit and make sure there is no corrosion on the wire connections. The voltage generated in this type of system is so minor that any resistance due to corrosion will cause the system to intermittently light or not light at all. Sometimes all it takes is to unhook and reconnect the wires onto the terminals to establish a good connection.

 

[Kelly Gordon]

I went out and looked, and I can't tell which type of heater we have. It's a Raypak RP 2100, if that helps. I know ours has a thermopile, because it was replaced a few years ago. Would the serial number help me make the final call?

The cost seems a bit extreme, does't it, Pool Clown? It's a pool store that quoted us between $350-$450 for the value, another $100 for installation. I've thought about calling our local heating repair company to see if they would charge less. But they've been reluctant to work on a pool heater, in the past.

I'm not a tech, so if I was going to replace the switch, I would need some step-by-step instructions. My husband has run a series of safety circuit tests, but that was a while ago. If we should do that again too, please send instructions (or a link). It's a little above my pay grade, but I'm skeptical about the pool store's diagnosis, so I don't see many options.

 

[danpik]

Here is a diagram (basic) of the inner workings of a millivolt pool heater.



If you jumper across terminals D and F, and the unit lights then the problem is somewhere in the safety circuit. (NOTE: THIS IS A TEST PROCEDURE ONLY. DO NOT RUN THE HEATER THIS WAY AS THERE IS ABSOLUTELY NO CONTROL OF THE UNIT THIS WAY) If the heater does not light this way, the problem may be a bad thermopyle. you can check this by lighting the pilot light and connecting a volt meter to the D and E terminals and reading the voltage. Ideally, the voltage should be 750 Millivolts. However I have seen reading as low as 400 Millivolts still operate a gas valve

 

[Pool Clown]

Hi all:

But the switch to turn the unit on wasn't on? What does that mean?

Kelly, You need to either replace, or by-pass that switch (temporarily). The heater should not be firing with that switch on the side in the off position. If the switch has failed, and making contact/ not making contact (intermittent?), that may be your only problem.

 

[ps0303]

Something is up with that 2 dollar switch at least. Replace that, then re-assess.

500.00 for a gas valve?

I charge around 340.00 for that gas valve... And i'm expensive!

Well if they installed the line with no available union to get the valve off and you have to cut the pipe and then install new pipe and a union, $500 all day long in my area.

 

[Kelly Gordon]

Checking the system for voltage and safety circuit breakdowns is beyond our pay grade. I might pay our local heating company $90 to come over and give the heater the once over. At least then we'll get a second opinion. I'm starting to seriously doubt the pool store's diagnosis of a new gas valve. Because ...

This weekend, once again, we were able to turn the gas on, light the pilot, turn the gas valve to on and have the burners fire. Again, the switch and thermostat were in the off or low positions at the time. If we turn the gas valve back to pilot, we are able to turn the burners off but keep the pilot lit - which means I could turn the heater on again without having to go through the trouble of lighting the pilot every time. Is that safe? His reasoning is: it's the same thing we do with our gas fireplaces inside during the winter.

 

[danpik]

I am goin to go out on a limb here and assume you have a millivolt system. I am also going to suspect someone else messed with this heater before you got it and bypassed the On/Off switch. If you are not comfortable with checking things, then yes, have a heating company come out and look at it. The basics are the same as a gas fired home heater. A lit pilot light is safe. That is how these are supposed to work...pilot stays lit all the time( weather conditions will sometimes dictate otherwise). I am going to guess it is either a corroded connection causing a weak voltage signal or a weak thermopyle.

 

[Kelly Gordon]

Thanks Dan. The on-off switch has worked in the past. The heater had a lot of problems last summer; I can't say for sure this was one of them, but when a number of things are going wrong at the same time, it's hard to say if the on-off switch worked correctly last year or not.

If this does NOT sound like a gas valve issue to the wise users of this board, I will probably cancel the gas valve replacement our pool company has scheduled, and have the heating company come out and look at heater instead. They don't really like messing with pool heaters, but I think I can sweet talk them because a Raypak is so universal.

 

[ps0303]

From everything you have said, it does not sound like a gas valve issue. Sounds like something maybe has been bypassed in that the unit fires up without turning the switch to the on position.