Weil McLain AHE help?

Glenn Harrison_2

I was just looking over the book for the AHE Series 4 on the WM website, and noticed the control in there is the boiler control module, not just an ignition control module. This control does have diagnostic lights on it, so my first question is, what are the lights doing when it locks out? the lights should head you in the right dirrection. I'm also a little puzzled by the fact that you have to reset the emergency switch two or three times to get it to work again. If the control is locked out, you really should only have to reset it once to get it to recycle, and start running.

Ken_8

We have an AHE intermittent flame failure...

that's blowing our mind. We installed this Series 3 AHE around 6 years ago. Worked fine until last summer. The indirect would call and the AHE would "lock-out." Flipping the power on and off a few times would reset the unit and it would work fine for a week, then fail again. On a few cool mornings, the problem also ocurred with the heating zone as well - somewhat ruling out a ZV end-switch failure. The odds of both end switches being intermittently bad at the same time being so remote as to be impossible.

After increasing frequency of lock-outs and finding nothing wrong when there, we wanted to just change the control module and found an upgrade, requiring new ignitor, harness, gas valve and module necessary because of "obsolesence." So, we changed it all. This basically negates the old diagnostic flow chart for the Series 3 and makes the unit a "hybrid" closer to the series 4, but not really.

The unit ran fine until two months ago. We are now back to square one and it craps out two or three times a day; can be refired by flipping the emergency switch on and off two or three times - and it's getting worse!

My guy called W/M and spoke to a desk jockey who simply read the flow chart diagnostic routine we already exhausted.

The resistence of the HSI is perfect, the propane pressure is perfect and the air proving switch, zone valve end-switch(es) and all 24 VAC values are on the money.

Anybody got an idea we haven't already tried?

The real **** is the job is an hour and twenty minutes one way!

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tim smith

flame failures

Next time you go out, which it sounds like will be soon, check your flame signal to the module. You will have to look up in the new kit paperwork for what microamps it needs. My guesss would be that either you have a poor ground, poor pilot flame or combination. The other thing could be is a draft problem, check the flue and the inducer fan wheel. Just a thought. Good luck, Tim

Empire_2

Ground?

I would check for a good mechanical ground. Also make sure the polarity on the line side of the 120 vac is correct. Also, is there a sererate flame rod? If so what is the micro-Amp reading?

Kal Row

this is going to be tough... cause...

when the control senses a failure it locks out requiring you to reset the primary power source - so you loses the cause

i suspect the air pressure switch due to an intermittent flue restriction - or a blower that starts too slow -

i would just run the flue out the nearest window for testing purposes

pull the top and make sure it not full of junk

spray wd-40 into and re-seat every connection

also the 24v transformer could have lost a few winding with an internal short - or if also powering outside items - could be overloaded by a bad ZV and causing the control to get funny - check it out

Ken_8

Thanks Tim & Mike

We also thought "ground" and reset and tightened all existing grounds and added an aditional one as well!

I am unaware of any flame rod on an AHE, just flame rectification through the HSI. We did check the signal output, but perhaps used the wrong value, since we are neither quite a series 4 nor a 3...

Anything else you might think of?

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Ken_8

Thanks Kal,

A few "original" ideas there fer sure... I'll try each one.

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Dan Foley

Ken

The Fenwal HSI systems that used the HSI as the flame sensor were notoriously unreliable. I have never worked on the AHE but I worked on hundreds of Amana HTM's that used the same or similar ignition set up. Rheem and Trane also used a similar HSI/sensor ignition system 10+ years ago but came out with conversion kits to separate the ignition and flame sensor functions due to nuisance lock-outs. Any chance of converting back to the W-R cycle pilot spark ignition system? Good Luck! -DF

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tommyoil

would it happen to have

a tri delta pressure switch?

ed wallace

lockout problem

also check to make sure the blower assembly is air tight if not the end switch/sail switch may not be making

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Ken_8

T,

Not quite sure what a tri-delta switch is.

But if I drink enough beer before heading out, I may find it more easily?

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Nron_13

check flame roll out

> Not quite sure what a tri-delta switch is.

>

> But

> if I drink enough beer before heading out, I may

> find it more easily?

>

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> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 68&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

Nron_13

check flame roll out

check flame roll out switch at the burner and if there is a blocked vent switch at the to they sometimes fail when they get warm and work when there cool , also check wirring for a good circuit 1 poorly made wire is all it takes , and its a rare occurance only seen 1 in 20 years

Alan(CaliforniaRadiant)Forbes

If you've got

24 volts at the ignition control module, that means your safety string (high limit, fan prove, flame rollout and spill) is satisfied. It's got to be somewhere in the flame rectification.

I used to love installing AHE's until one ran away, i.e. operating limit failed, high limit failed and then the relief valve stuck closed; and then the thermostats that control the by-pass on two others failed. And what put it to bed was the tech. supoort guy reading out of the manual.

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Unknown

Ken what did you use

for a retrofit I need make and model of module, ignoter, gas valve if you will. I will then be able to give you some assistance. In the meantime it sounds like a possible combustion issue may be going on with the unit. One of the things I first do with HSI Igniters being used as a sensor is to install a seperate sensor and use the ignter only to light the burner. Position the sensor 1/4" to 1/2" above the last burner in the series to light and make sure it is about 1" into the flame. Attach a microamp meter to it and you should read somewhere between 2 to 10 microamps.Normal is about 3 to 5.

Get me the rest of the information and I will get back to you.

Robert O'Connor_7

Ken & the AHE...

Ken, we had 2 go bad on us about a year ago (same problem) as it turned out both transformers came through with reverse polarity. I found it it hard to understand how it worked for 6 years (sounds like a similar batch, age wise that is). Did you get it from Nutley by chance? I'm just thinking along the line of a facory problem, and all of them getting shipped together. Had the power gone out recently? Both of these units experienced power outages at different times as well. Good luck!

Robert O'Connor/NJ

Steve Miller

What Kal said

I wouldn't run the vent out the window temporary, that would change everything as far as the pressure switch. Actually check the pressure switch with a magnehelic while the thing is running and watch the pressure and see if if gets close to where the pressure switch contacts open. I've seen vents run to over the max of the equivalent lenght and work for years and the diaprham of the pressure switch weakens and starts tripping. Here's a link to the manual I just grabbed online. Everything to troubleshoot seems to be in there. Good luck, Steve

http://www.weil-mclain.com/FTP/AHE/AHE_Manualnewpage.pdf

Kal Row

my idea was that if you do change things..

and it starts to work - then at least you know what the problem area is - basic troubleshooting...

Unknown

Ken if you have

a United Technologies Integrated Boiler Control 1013-200 it has a couple of features built in. It must prove flame in 4 seconds for one thing. It will recycle twice before going into lockout. The igniter warm up is 30 seconds and it does have pre and post purge features. After one hour it will retry three time again (soft lockout).

If polarity is reversed the control is polarity sensitive, if it is reversed it will flash the power light when powered and will not cycle the boiler.

Ken_8

A huge thank you to all those who posted

their suggestions!

If what we did a few days ago backfires, one of the suggestions offered will lead us to the solution. Tim, the depth of your knowledge of this stuff incredible. I'll ask my the tech who's doing the work to read all the responses and we'll make sure these points are specifically tested out - should whatever he did last time fail.

Thanks again!

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Unknown

Ken hope it all works out

if not give me a call. Glad to help out.

Kal Row

had yet another fenwal hsi sys with bad ground this week...

someone could make a career out of just these

ps this one was on a laars pool heater

Kal Row

say dr McElwain - do you know what method they use...

for flame sense when there is no separate flame sense rod?

do they measure resistance change in the HSI, or thermocouple effect voltage produced by it, or the ac signal rectification of by the dissimilar metals in the HSI in a flame’s ion stream, or rectification of an ac signal applied to ground and one leg of the HSI? This info would help in troubleshooting – I could use a portable oscilloscope in the sense circuit to see what the control sees – could not find this info on fenwalcontrols.com

Empire_2

Correct me if I am Wrong, But

I believe that it still uses DC flame rectification. Checking the circuit is a pain ,but it can be done. After to hsi is denergised, the rectification circuit kicks in and uses the same wires.

Unknown

Kal most HSI systems

that use the igniter as a sensor use the ground leg with a superimposed signal rectified through the igniter to ground (the entire burner area). I developed a switch which makes it a lot easier to test these. I made the mistake of giving one to a control company rep and a year later they had one on the market for $49.50. You can make your own for less than $15.00 including your labor.

I will e-mail you a copy of the procedure.

Kal Row

thanks a bunch...

kalro@pobox.com

Ken_8

Thank you all!

I just wanted to thank you all - and let you know what's going on. I have emailed the client, who is my son's father-in-law (as well as a good friend) and after a week now, has not had a flame failure since we were last there.

We tested just about everything you guys suggested (missing, unfortunately, a few that we never thought of - that you suggested may be THE problem), but seem out of the woods so far and we basically checked every sta-con, wire nut and contact point in the entire boiler and cleaned anything that looked even remotely tarnished. Because we did not find anything specific wrong, we have no faith that our good fortune was anything but luck - and that the problem will recur. Thanks to all you guys, I now have a plan of attack and support from the wizards of our world, and may call for further clarification of points made in the thread above.

This is an amazing place; and I thank you for making it so. I'm printing the entire thread so my tech can take it along when we get the next call. That would be the call I hope we never get, but know I probably will...

Have a great weekend and thanks once again,

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Unknown

I am not quite ready to quit

on this as I need to know if the Integrated Boiler Control is the United Technology control I mentioned in a thread above. The reason I am curious is that at OilStock a fella had brought one for me to look at. He claimed they have changed three of them and are still having the same problem. The problem is very similar to what you are having happen.

In addition two of my recent students when we covered those controls in class stated they had been changing a lot of them.

I am wondering if we have a possible case of defective controls.

I would talk to WM engineering and see if that is the case, you may not get a straight answer from normal calls to them you need to get to the engineers.

Ken_8

Thanks Timmie,

I'll ask the tech that was there, what brand/model he found. I am 99% certain it is now a Fenwal however.

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