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Thread: Updated - Hayward H400 Series heater problems - Help!

  1. #1
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    Updated - Hayward H400 Series heater problems - Help!

    Update to my original post below. I may have misdiagnosed the original issue. AFter checking the blower and fixing the air sensor on the post side of the blower I still have the same issue. It runs for several minutes and then something clicks or appears to try and shut down the heater. The flames almost die out and then it clicks again and the flames pick back up and starts to run normally again. Not sure if the click is the gas valve opening and closing, a sensor, or the heater ignition re-firing. If it was a sensor I would think I should get some kind of diagnostic failure code. I never get a code and the unit never shuts down. The Green heater light stays lite as if its functioning normally. The unit is hooked to an auto cut off device (stingl 500) per the new Virginia Baker act. The only interaction between the 2 devices is a line spliced into the water pressure switch sensor wire. I am assuming this is to only allow the heater to operate if the Vacuum cut off device is in the proper run mode or turned on and running the filter.

    Any ideas or suggestions? Has anyone had this issue?




    I have been troubleshooting an H400 series Hayward heater. Electric (non millivolt) H400 series. Newer version with Digital control panel. I find a lot of information regarding the older models but not the newer version. My H400 was purchased about 4-5 years ago. Its been used 3 seasons.

    I may have 1 or possibly 2 problems. The other day I cleaned the burners out real good. They were clogged and had a lot of build up. I Checked the heat exchanger and it looks ok. I Placed the heater back together and it started perfectly. So quiet I didnt even think it started. It burned perfectly for 5 minutes then the blower would make noise like it was pulling or having trouble venting. Almost like It was trying harder and bogging down. The heater starts making a clicking noise as well. Sounds like its relighting the burner. Fan noise and Flame height start to go up and down, up and down, etc... Until you turn it off or place it in standby.

    So to recap it will ignite normally after being turned off for a while but then after running a while and shutting it off it will only ignite after several tries with a large poof! It eventually ignites but its like a mini explosion.

    The other issue is the fan seems to bog down or not be able to vent after running for a few minutes. The up and down flame issue described above goes along with this. I tested the 2 hose lines that connect to the fan housing and when I apply pressure to the line one of the lines makes a healthy clicking noise as if the diaphram is working and the other does not. They both hook into the same round shaped type of Diaphram device. I believe they simply detect air flow. I believe this part could be bad and if so would it cause this issue?

    If so does anyone have the part # for the Diaphram? Both are sensors to make sure the fan is running but I cant find them on a parts list. I tested both by applying very little pressure to the hose via my mouth. Where can I find the part number or description. I downloaded the manual but it doesnt list this particular part.

    Thanks in advance!

    Steve

  2. #2
    Mod Squad Bama Rambler's Avatar
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    Re: Hayward H400 Series heater problems

    tested the 2 hose lines that connect to the fan housing and when I apply pressure to the line one of the lines makes a healthy clicking noise as if the diaphram is working and the other does not. They both hook into the same round shaped type of Diaphram device. I believe they simply detect air flow.
    That sounds like a differential air flow switch. If it is, applying pressure to one side will activate it but applying pressure to the other won't. It sounds like it's working normally.

    It sounds like your blower is heating up and bogging down. Did you oil the bearings when you had it apart?

    If it's slowing down then it won't have enough flow to keep the flow switch made and it would "click" it in and out like you describe.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
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    Re: Hayward H400 Series heater problems

    Thanks Bama Rambler! I appreciate the time.

    Is that what its called. A differential air switch. The name make sense. I actually have 2 of these with seperate hoses going to 2 different air differential air switches/ sensors. They are located right under the control panel in the upper section. The one that is not clicking is attached to the out vent post blower area on the opening. Where the air vents out. They look like the same exact thing. Each with seperate hoses attached. The blower itself never occured to me because it seemed so unlikely but I will check it over and lube it. I believe it was ok but Ill look it over. What do you lube with? Do you think this air switch could be causing problems? Why its not listed on the parts diagram and should it be clicking like the other one when slight pressure is applied?

    If needed does anyone know this part # or where I could get one?

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    Re: Updated - Hayward H400 Series heater problems - Help!

    Just want to say I am getting quite an education by surfing and using this forum. Although the heater I am troubleshooting just says H400 on it I have figured out from researching the site that I have this model "Hayward H-Series Low NOx Induced Draft H400IDL2".

    I am posting this new post because I have had so many revelations since my first post. I am thinking that my problem is in the gas line or gas valve. Its a natural gas fed system (yankee gas) and The meter was originally to far from the heater. The feed is only a 1inch or 1 1/4 inch line. The distance would have required we have a 2 inch feed/pipe. I found out that last year a regulator was installed right behind the heater to solve this problem. It did run ok for a while with the new regulator. The system I originally described may simply be my heater is not getting enough gas or gas pressure to operate normally.

    I dont have a manometer so I was wondering if there was any other way to check the valve or verify its operating correctly?

    Thanks!

  5. #5
    Senior Member spishex's Avatar
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    Re: Updated - Hayward H400 Series heater problems - Help!

    Sounds like you might have a loose connection. Maybe between the IID and the valve since that wouldn't give an error. But if it's happening that quickly it might not throw an error anyway, so it could also be a safety circuit issue. If you've got a volt meter/continuity tester handy I'd test the safety circuit first (pump on, heater off). Hook it up and start jiggling wires.

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    Re: Updated - Hayward H400 Series heater problems - Help!

    My heater (same model) does the same things. We replaced the water pressure switch, the circuit board and the hoses on the fan. The gas pressure was checked and was fine. Igniter is fine, you can watch it ignite; We are not sure where to go from here either. Like you (and other hayward posters) after something is replaced, it works for a while, then starts acting up again. I'm begining to wonder from all of the posts if the unit isn't defective in some way. All tips for fixing are welcome!

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    Re: Updated - Hayward H400 Series heater problems - Help!

    Hi all -

    Reviving this thread as it sounds like I'm having the same type of problem with my H400.

    Steve - were you able to find a fix for your problem?

    Thanks!

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    Re: Updated - Hayward H400 Series heater problems - Help!

    We thought it had something to do with the fan, because when we replaced the hoses, it would work fine.....for a while. We had a tech out, who said the wiring was wrong on the unit when installed. It was shutting off when the pump turned off (it should have stayed on and had the fan cool it). He rewired it, but after a few minutes of running, the fan seized up and blew up. It had caused so much damage by the time it was rewired, it was too late. Repair vs. replace....$ wise, it was replace. I gave up! We ended up replacing the unit with a pentair 250; it has worked perfectly! It uses less gas, and heats up the pool at least three times more quickly. Very happy, no stress!

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