Heater failed after turning on 1 week in service

[Jeff.williams]

Guys - new pool install with Hayward H500 natural gas heater. Bypass installed for start up, flow meter for correct flow rates per manual. Large spa - 12x12 approximately. Keep getting LO and lockout when heater gets water up to about 75-80 degrees. Warrant company comes out and checks and replaces almost all sensors... Test runs the unit again, same thing. Now they are saying the unit’s heat exchanger is bad due to a 50 rise in temperature and a high limit lockout. The heat exchanger is not moving the heat away and over temping. Hayward is assuming heat exchanger damage now due to the temperature rise of just over 50 degrees... They are now telling us that is due to poor water chemistry. The pool was started around Thanksgiving and the heater was bypassed until just around Christmas when it was used to heat the spa and at about 90 we had a LO for high temperature right off the bat... Hayward now refuses to warranty the unit sighting poor chemistry. The water tested - see attached - not too far out of “normal”. No one has taken the heat exchanger out. They are assuming this due to the rise in temperature. See photo of coils attached too. Any ideas??

Thanks
Jeff

 

[JamesW]

Do you have a picture of the whole system?

It's probably a plumbing misconfiguration causing insufficient flow to the heater.

 

[Jeff.williams]

baffled

 

[Jeff.williams]

Do you have a picture of the whole system?

It's probably a plumbing misconfiguration causing insufficient flow to the heater.

James,

I do not have one handy, but I do have a flow meter on the system and am getting around 90 gallons per minute with the pump at 100 percent and it still kicks out with the LO alarm at about 76 degrees. Again, Hayward is claiming damage to the hear exchanger...

 

[JamesW]

I suspect that the plumbing is incorrect and that the flowmeter is in the wrong place.

I don't think that the chemistry has anything to do with the problem unless the heat exchanger is completely scaled due to prior bad chemistry.

When was the plaster completed and what has been the chemistry since startup?

 

[Jeff.williams]

I suspect that the plumbing is incorrect and that the flowmeter is in the wrong place.

I don't think that the chemistry has anything to do with the problem unless the heat exchanger is completely scaled due to prior bad chemistry.

When was the plaster completed and what has been the chemistry since startup?

Pebble Sheen was completed right before Thanksgiving. Filled in 3 days. Chemistry is right inline as of today and has been from what I understand from the guys that helped me build this thing. I have built many pools in the last 12 years but had taken a break for a while and decided to do this project at my home. The gentleman that helped me has been building pools here for over 30 years. I just handled the "nerd" stuff while he did the construction side. See photo from tonight attached. Flow meter is installed where the heater manual indicates it should be installed. Have a bypass built to go around heater and that is what I did during start up. Did not let water into heater for several days at start up...

 

[JamesW]

That looks correct. Are you sure that the valves were set correctly during operation?

Do the heat exchanger tubes look scaled?

Maybe it's an issue with the internal bypass.

BYPASS SERVICE CARTRIDGE:
The following procedure details how to remove and replace the internal pressure bypass valve in the
header. This procedure applies only to plastic (non-ASME) headers. On bronze (ASME) headers, the bypass
service cartridge is not field-replacable. Please contact Hayward technical support for more information.
1. Turn pump, main gas valve, and heater power off.
2. Drain heat exchanger according to instructions in Section III of this manual.
3. Remove 6 screws and remove the upper plastic heater side panel, to allow access to the header.
4. Remove the cartridge retaining nut from end of header (see Figure 24).
5. Slide out the bypass cartridge from the end of the header (see Figure 24).
6. Check the function of the bypass valve to ensure the valve flaps rotate smoothly on the shaft, and the
spring fully closes the valve.
7. Apply silicone o-ring grease (Hayward Jack’s 327 Multilube p/n SP032712, or equivalent) on o-ring
seals on the bypass cartridge before inserting into the header.
8. Insert bypass cartridge into header with the arrow on the end of the cartridge pointing up.
9. Re-install cartridge retaining nut. Nut should be tightened hand-tight only. DO NOT OVER-TIGHTEN.
10. Re-install the upper plastic heater side panel

 

[Jeff.williams]

That looks correct. Are you sure that the valves were set correctly during operation?

Do the heat exchanger tubes look scaled?

That is what they are claiming... 50 degree rise in temp. that they do not like. Do you have an opinion on these heaters and who makes the better one? I am really blown away... I have never had anything like this happen before and the bad thing is, it is my personal pool and was going to be a model for our company. If we screwed up, I need to own that but if it is just bad equipment and this is the way Hayward is going to handle it and it is not something we did, I am not so sure that I want to use their equipment any longer... see photo. They are saying this 50 degree rise in temp is due to scaling... It does make a little sense sense the unit's exchanger is not able to unload the heat to the water and make the transfer of energy work but wow... Maybe the Titanium unit from Pentair is the way to go. It is very pricey though!

all sensors and bypass was replaced. Main control board, all flame sensors, cut out switch, etc. all replaced... they were throwing parts at this thing like crazy...

 

[JamesW]

Were the valves set correctly every time that the heater fired?

Part of the problem is that heaters don't have a flow switch. They have a pressure switch which can be activated with no flow, which is a bad design.

I don't see any scale in the exchanger tubes.

Do you see scale in the tubes when looking directly inside with a light?

 

[Jeff.williams]

Were the valves set correctly every time that the heater fired?

I don't see any scale in the exchanger tubes.

Do you see scale in the tubes when looking directly inside with a light?

Yes, the valves were set. They were open. I do not see any scaling myself but they (Hayward) are saying that the rise in temp is due to scaling.

 

[JamesW]

Were all the valves open?

If there is scaling, you should be able to see it.

 

[Jeff.williams]

Were all the valves open?

Yes, they were ALL open.

 

[Jeff.williams]

I am considering this unit:
ETI 400 High Efficiency Gas Heater

 

[JamesW]

It's an expensive heater.

 

[JamesW]

Yes, they were ALL open.

If all of the valves were open, that's the problem. Two valves bypass the heater.

 

[Jeff.williams]

It's an expensive heater.

True, you could buy a lot of gas for that price! But the titanium heat exchanger is what I like about it... My spa is about 5000 gallons and that is why I went with the Hayward 500,000 btu heater... But I am not impressed. They are telling me that it will be 1300.00 to fix it...

 

[Jeff.williams]

If all of the valves were open, that's the problem. Two valves bypass the heater.

If all of the valves were open, that's the problem. Two valves bypass the heater.

NO, the bypass valve was closed and the other two were open. It was correctly configured for water to go the heater and out of the heater while the bypass valve was closed.

 

[Jeff.williams]

If all of the valves were open, that's the problem. Two valves bypass the heater.

NO, the bypass valve was closed and the other two were open. It was correctly configured for water to go the heater and out of the heater while the bypass valve was closed.

 

[JamesW]

There are two bypass valves.

Both are closed in the picture.

Is the configuration in the picture the same as when the heater fired?

 

[Jeff.williams]

There are two bypass valves.

Both are closed in the picture.

Is the configuration in the picture the same as when the heater fired?

I think that you are looking at this picture incorrectly. Water flows into the back and out the front. All valves from the filter to the heater are open and from the heat to the spa return are open. The only one that is closed is the valve that allows water to bypass the heater. The handles are confusing, I know that now that I look at the pic. They are Hayward valves and while the handles are perpendicular to the flow direction, they are OPEN...