H400ED1 heater issue

[Warren3000]

I have an older Hayward H400ED1 heater it just recently started acting up. When I switch it on you can hear the electric igniter for a few seconds and then the flame fires up. About 3-5 seconds later the flame cuts off. There is a "system normal" and "heating" light the system normal light stays on the whole time while this happens and the heating light comes on and off with the flame. One thing I noticed is before when the heater worked properly when I would turn it on you can hear the igniter and once the flame kicked on the igniter would kick off, but now when the flame kicks on I can still hear the igniter for the few seconds while the flame is on then once the igniter cuts off the flame shuts off as well. Its almost like the heater thinks the flame wasn't ignited after several seconds (when it actually is) so it cuts it off.
Is there some kind of sensor that tells the heater once the flame is on that I can clean or replace. What do you guys recommend?

 

[ps0303]

The ignitor is also the flame sensor. You can try cleaning the ignitor with steel wool and see if that helps any. If not, sounds like you might need a new ignitor.

 

[Warren3000]

The ignitor is also the flame sensor. You can try cleaning the ignitor with steel wool and see if that helps any. If not, sounds like you might need a new ignitor.

Thanks, I took out the heater element today to get to the igniter and in the process the wire fell right out of the igniter it was pretty corroded. I just ordered a new one (part # haxign1931) hopefully that will fix it. I was just wondering how does the igniter also act as a flame sensor I only see one wire going to the igniter for the spark how does the heater get feedback from the igniter that a flame is present?

 

[danpik]

If you look up Flame Rectification on Google, there is a fairly technical explanation of how it works. In a nut shell...Once the power for the spark shuts off, the control board holds the gas valve open for about 3-5 seconds without using the flame sensor circuit. This is to establish a good gas flow/flame pattern. Durring that 3-5 second time frame, the flame rectification circuit from the board turns on and sends a small voltage (millivolts) to the igniter/sensor. As long as the flame is burning, the carbon present in the flame acts as a path to ground for the voltage from the board. If the board senses voltage flow (current) then it knows there is fire present and keeps the valve open. If the flame is not present there will be no current flow and the board will shut down the gas valve after the 3-5 seconds

 

[ps0303]

Yes, what he said....^^^^^

 

[Warren3000]

Success, I replaced the ignitor assembly and it works again. I noticed the new assembly has an updated design, The metal frame of the ignitor has a half-circle section that kind of wraps around one of the heat tubes for more stability or something. The original one didn't have that. Anyway thanks for your help

Oh, I forgot to mention there was another issue. Once the heater is on It works fine for about 5-10 minutes then cuts off (both the system normal and heating lights turn off when this happens) for about 30 seconds and kicks back on (heating and system normal lights come back on). It seems to happen more often as the spa warms up, at first when the waters cold itll last 10 minutes before it cuts off then when it is almost fully heated it happens around every 5 minutes. I jumped the temperature sensor on the outlet and that didn't change anything so It cant be that, Any ideas?

Do the older ed1's have trouble codes? Im guessing they must hence the system normal light. If so how do I get the codes?

This is the sensor I jumped



does anyone know what these two sensors are for and I cant seem to find replacements for them if they are the culprit.

 

[ps0303]

No codes on this oldie. This unit should have two sensors like the one with the boot on it. Check the other side of the unit.

As for the other two in the bottom picture, those go to your thermostat knobs. In order to replace them, you have to replace the thermostat control unit behind your temp knobs. I sort of doubt that is the cause of the unit doing what it's doing now. What appears to be happening is the unit is thinking it's getting too hot and shutting down and then cools off and lights back up. I would also wonder if the bypass inside the unit is is=n good shape. If it's broken though, I would suspect the unit would do a loud banging sound like rocks rolling around inside as it tries to heat up.

 

[Warren3000]

It looks like the second one will be #17 on this parts illustration Hayward H-Series Heater - (ED1 Style) Replacement Part Schematic It looks like its either on the top or bottom of the header assembly from the heat exchanger i will look for it tomorrow and jump it as well and see if anything changes. Now that you mention the sound i do hear that sound but only when the heater is running and fully warmed up and i cut off the water pump, but i think this is just the water boiling and metal slightly expanding from the water not circulating and getting very hot in the heat exchanger.
Should i unbolt the front header off of the heat exchanger and check if everything is ok or due i risk damaging something else due to the old age of the heater.

 

[ps0303]

If you shut the pump off, the heater shut shut down as well and not be running. If for some reason the hater is still running when the pump shuts down, I would wire the heater to the timer clock just like the pump so it does in fact shut down at the same time.

If you do unbolt the header, be careful because if you break off one of the bolts, you could be screwed.

 

[Warren3000]

Yes, when I shut the pump off the heater shuts off with it and those noises I was talking about only last a few seconds.

I went out and looked over the heater again. There is in fact only one temperature high limit sensor on the front header. I think i was previously confused by the parts diagram because it shows 2 different high limit switches but one is for heaters made after 10/28/00 (part #16 shows high limit switch on the side of the header which is what I have) and part number 17 shows the switch on the top or bottom of the header which I don't have. Could the second high limit switch maybe be located somewhere else?

and next after you did mention the sound of rocks bouncing around I listened closely and there does appear to be a similar sound coming from the front header when the pump is running. But it its not very loud you can barely notice it unless you put your ear right up to it and I thought it was normal the whole time. Here is the sound H400ed1 front header noise - YouTube Could this be the bypass going bad? if so I will have no choice but to take the front header off.

 

[ps0303]

Sounds like something inside is rattling. I would inspect inside the header and see what you might have going on. Just be careful removing the nuts.

 

[Warren3000]

OK, well I have good news and bad news. Good news is I found the problem it was the thermostat the body of the thermostat had punctured and the wax material came out. I verified by putting it in a pot of water on the stove and the thermostat never opened. The bypass valve was still ok but I ordered a new by pass kit anyway (part# haxbpk1931) since it comes with the pressure spring rod thing (mine looked kind of corroded) and a new gasket for the header. Now the bad news, one of the studs broke off while I was unbolting the header (I did not force it much but it broke anyway) it was one of the studs on the lower section. Do you think it will leak? there are still about 10 other bolts that hold it on. if it does leak what can I do?

 

[ps0303]

Yuuup, as I suspected one would probably break. This is the reason when I come upon one of these oldies and the bypass is suspect, I just replace the heater. All I can tell you is to cross your fingers. If it doesn't leak right away its only a matter of time especially when it starts heating up and gets under pressure. You can try putting lots of lube on the oring as well to see if that helps. If it leaks, well not much you can do. You could try some blue RTV but nothing for sure will seal it for ever. I would suggest that you start saving your pennies for a new heater.

 

[Warren3000]

With a bit of luck and ingenuity I was able to get some good results. I drilled out the rest of the broken stud and threaded in a similar size sheet metal screw and it went in nice and tight. Everything seems to be working great so far with no leaks. That noise of rocks bouncing around in the header is gone. There was also a nice side effect to this repair. I have increased water flow from my pump, I believe this is due to the old piston rod and spring in the bypass being rusted solid and bottlenecking the flow.
Here are some pics. Thanks for your help! Now I have one last issue with my pool. The water in the spa slowly drains down when the pump is off (about an inch every six hours) I think it drains into the pool. I cant seem to figure out where and how its doing this.

You can see the different bolt in the middle compared to the other original ones.


New piston rod and spring, (new plastic bypass not pictured)new thermostat and new o-ring.

 

[ps0303]

Looks good.

The spa draining is because you have a check valve in your piping for the spa that is bad and needs to be replaced.

 

[Warren3000]

yea that's what I thought and then I replaced the check valve for the spa pipe and installed new diverter valves as well. still does it. Can there possibly be another check valve in the piping under the ground?

 

[ps0303]

Maybe but I would hope not. What does your piping look like?

 

[Warren3000]

The 3 jandys are new and the check valve below is new