Gas supply line issues for pool heater

[cptkirk]

I've been troubleshooting a problem I've been having with intermittent failure to ignite issues with my Hayward H400FDN (which are detailed in another thread), and in the process have been taking a good look at the installation/service manual and comparing it with how my system was installed. There are a couple of issues with the gas supply:

• Looks like the supply run from the meter to the heater is the neighborhood of 50 effective feet after accounting for the elbows. The specs says the supply should be 1 1/4" for my size heater, but they only installed a 1" supply. The pool heater is the only appliance on this part of the supply.
• The specs also say that the supply size should only be reduced at the gas valve, but the plumbers reduced to 3/4" immediately after the regulator. From there, it goes through a 3/4" flex line that is too long and therefore has a looping twist in it before it goes into the final rigid pipe section with an elbow that goes into the gas valve. All told, it's probably going through at least 6 feet of 3/4" inch supply before it gets to the valve. To top it off, there is no union as recommended, so removing the manifold/valve assembly to inspect the burners probably requires disconnecting at the flex. I'll add some pictures later when the weather gets better.

I'm sure the plumbers did not look at the manual and just did what they thought was sufficient/easiest for them. This was all done as part of house construction, and I did not have the knowledge or experience to know the work was not up to spec. Lesson learned on that. My questions are:

1. If I get a manometer and find that I am still getting pressure within spec at the gas valve outlet, is all this still a problem that needs to be addressed?
2. If the pressure is out of spec and can't be adequately compensated by making an adjustment at the gas valve regulator, does the existing supply need to be ripped out and redone, or or there other options?

Thanks for any input you can provide.

 

[HermanTX]

From there, it goes through a 3/4" flex line that is too long and therefore has a looping twist in it before it goes into the final rigid pipe section with an elbow that goes into the gas valve

You may want to check code for FL. I was informed the code is all plumbing to the heater must be hard piping (no flexible pipe). Also must have a water trap to catch condensation.

 

[BassPlayingDude]

Is that natural gas or propane?

 

[PoolGate]

Pipe size can be lowered if the pressure was increased. When my heater was plumbed they added a high pressure port to the gas meter to supply the pool heater. No issues to date!

 

[cptkirk]

Natural gas. Besides the flex, there is no water/sediment trap. But the work was all inspected I believe, so I assume it met local codes (at least at the time).

 

[cptkirk]

Out of the meter, there are branches that each individually go to two different tankless water heaters, a gas grill/burner, and to the pool heater (so four branches in all). There is nothing to increase the pressure going to the pool heater that I see.

 

[Candurin]

Seems like you should be OK at 50'. I had to run 1-1/4, but my run was over 100'.

 

[cptkirk]

I'm just going by what it says in the installation manual, which says that for my heater size, the supply should be 1 1/4" for anything up to 100 feet. But to go back to my original question, let's assume the installation meets local code. If the pressure is within spec, is this still potentially a problem with heater operation?

 

[cptkirk]

Let me restate my question so my intent is clearer. If the pressure is within spec, is that sufficient for the heater to operate as it should, or is it possible that because the supply lines are smaller than they should be it may not be getting sufficient flow for the burners to operate properly even if the pressure is within spec?

 

[duckcmmndr]

Let me restate my question so my intent is clearer. If the pressure is within spec, is that sufficient for the heater to operate as it should, or is it possible that because the supply lines are smaller than they should be it may not be getting sufficient flow for the burners to operate properly even if the pressure is within spec?

Pipe size will effect flow, not lots of difference between 1" and 1 1/4", but when you step down to 3/4"...big difference. You mention a regulator and the reduction to 3/4" flex pipe, I assume this is at the pad by the heater? I think this may be where your problem is.

 

[cptkirk]

Below is a picture of the supply near the heater. It is 1" coming out of the ground into the regulator. Then immediately after the regulator there is a reducer, then the 3/4" flex, which leads into an elbow then hard pipe into the gas valve.

 

[PoolGate]

That looks seriously amateurish! This is mine below. Very professional, clean job. Your plumber should have cut and threaded a pipe onsite where that flex pipe is. Also I have never seen a professional gas plumber use Teflon tape. Can you smell gas around that area?

 

[cptkirk]

I don't think there are any leaks, but I'll do a soap test when I get a chance. The plumbers were a crew that my contractor regularly uses, but they were stressed and busy and I'm guessing they did whatever was expedient, and I didn't know better to question what they were doing. I'm pretty sure the supply pipe from the meter to just above ground level near the pad was laid first, then the pool guys poured the pad and installed the equipment, then the plumbers came back to finish the connection.

 

[PoolGate]

I also don't see a sediment trap. It is code is some places not sure about FL. It is that tee right below the red shutoff valve in my picture.

Found this:

Violation : Sediment trap is missing or configured incorrectly
Code Sections : 2010 FBC-R SECTION G2419 (408) DRIPS AND SLOPED PIPING
2010 FBC-FG SECTION 408 (IFGC) DRIPS AND SLOPED PIPING
Comments : Contractor shall install a proper sediment trap at the gas pool heater (or wherever the sediment trap is missing or improperly configured)
Location of sediment trap:
Sediment trap is required to be installed downstream of the appliance shut off valve and as close to the appliance inlet as possible.
Sediment traps are required at all gas appliances:
Exceptions:
 illuminating appliances
 ranges
 clothes dryers
 outdoor grills
One way to remember the above is that if the flame can be seen (illuminating appliances, i.e., gas lights) or if the appliance is attended by the person operating the appliance (ranges, clothes dryers, outdoor grills), the person operating the appliance should be able to tell if the gas has stopped working – then a sediment trap is not required.
 All other appliances require a sediment trap – basically any appliance which operates automatically.
The above may be an easy way to help remember which appliances require a sediment trap and which do not.
Gas pool heaters require sediment traps; however, I frequently find that these do not have sediments trap installed.
When sediment traps are installed, improper configuration of the trap is common. The most frequent improperly configured sediment trap is where the gas supply connects to a tee fitting installed with the tee tap facing down, the gas supply is connected to one end of the horizontal tee, the appliance is connected to the other end of the horizontal tee, and a short nipple is installed into the down facing tee tap, the nipple is then capped. The gas, along with any sediment, flows through the tee, across the down-facing tap, and into the appliance … a sediment trap of this configuration (shown below) does little, if any, good.

 

[1poolman1]

Be aware that pressure is not the only thing that needs to be within specs. You have a heater that requires 400k btu of gas input. A 3/4" flex will only allow slightly more than half (from an online description of your flex: (Designed and Engineered for Safe, Optimal Flow Rate; Up to 290K BTU Flow Capacity), of the required "quantity" of gas that the heater needs to operate properly.

The instructions for that Hayward heater have this warning:
Attention : Do not use flexible appliance connectors
on any gas connections unless the connector is
CSA approved for outdoor installation, is marked with
BTUH capacity (which must be equal to or greater
than the heater rated input) and the type of gas (natural
or LP).

Italics are mine. Most locales do not allow that type of supply on a pool heater.

 

[Candurin]

Some states/municipalities do not allow CSST pipe outside. Some allow it only if protected (I.e. in a conduit).

I would go have a piece of 3/4" galvanized (not black!) pipe cut to the exact length you need at Home Depot and put that in ASAP. That's just lazy plumbers not cutting your pipe to the correct length. I cut my own pipe for our install. It takes 5 minutes to cut a pipe to length and thread it by hand.

 

[Candurin]

That looks seriously amateurish! This is mine below. Very professional, clean job. Your plumber should have cut and threaded a pipe onsite where that flex pipe is. Also I have never seen a professional gas plumber use Teflon tape. Can you smell gas around that area?

View attachment 329827

You don't have a sediment pipe/drip leg either, unfortunately. You should have a 3-6" of pipe below the tee, just under your shutoff valve. You only seem to have a tiny nubbin' of a nipple with a cap on it, which isn't long enough to actually prevent carry-through to the remainder of the line.

 

[Candurin]

Here’s our gas pipe (reduced from 1-1/4” arc-jacketed flex to 3/4” galvanized just prior to coming out of the wall.



Let’s see who can see what I did wrong (yet, somehow passed inspection)? I guess my mistake wasn’t critical, although I was fully prepared to address it on the spot.

 

[cptkirk]

You can't use flex/csst outside! I would go have a piece of 3/4" galvanized (not black!) pipe cut to the exact length you need at Home Depot and put that in ASAP.

It's not quite that simple, the pipes don't line up exactly, which is probably why they put in the flex rather than taking the time to cut and thread pipes to the exact dimensions required to line everything up with hard pipe. I do agree it was a poorly done job and if I had known better I would have had them fix it at the time.

 

[cptkirk]

You have a heater that requires 400k btu of gas input. A 3/4" flex will only allow slightly more than half (from an online description of your flex: (Designed and Engineered for Safe, Optimal Flow Rate; Up to 290K BTU Flow Capacity), of the required "quantity" of gas that the heater needs to operate properly.

This was really the heart of my question. I had already read the passage from the manual you quoted, but the tag on the flex had deteriorated to the point that I couldn't read any of the rating information.