High Microamps

Glenn Harrison_2

If you pull the burner you should replace the gaskets. This unit is far from maintenance free. In all reality, the burner should be pulled, the ignitor/sensor inspected for any signs of corrosion or decay of the electrode. If the burner has nott been pulled since 2000 when the unit was made, I can guarantee you the electrode needs to be replaced. When you replace the electrode, it comes in a kit that includes new gaskets. Also, you want to check the burner head. Make sure the screening has not burned thru or decayed anywhere. Also you want to shake the burner head, and if you hear any debris in the head you should replace it.

Another thing I like to do is pull back the removable insulation around the burner and check all the water connection eyelets for any signs of leaks. After 10 years, Lennox was never able to perfect their stanless steel welding techniques, so the welds on the tank are prone to leakage. if any of the eyelets start to leak, you will get water in the burner compartment, and this will quickly degrade the electrode and burner head.

As far as you thermister code goes, just make sure all the wire connections are tight. There is a molex plu near the top of the unit for the thermister, as well as the main connection on the board.

Last, as far a your leak goes, I had one unit that the gasket on the flue adapter started to leak. I went to remove one of the nuts and the stud snapped off. Wound up replacing the unit, which brings me to my next and most important point. Lennox is no longer making these units. If you have a leaky tank, They will provide you with an allowance for a power vented water heater, and a new 90% efficient furnace to replace the air handler, or a wall mount boiler with a storage tank and a 90% furnace depending on the application. So the first thing to do is determind the leak and if it can be fixed. If not, your customer is in for a fun time with Lennox to get the equipment replaced.

rob

Excessive microamp signal

Awhile back we discussed high microamp signals and the cause or problem that it may create/indicate. I failed to archive the thread and can not locate it in the search. Recently, a tuneup on a Lennox CompleteHeat HM30-150-3 5800L yielded ua in the 13-15 range. I wondered why, unless this unit in general runs higher than normal because of the powerburner or design. Thanks.

Unknown

Normal for most

systems is 2 to 10 microamps. What kind of problem are you having? Also what is the electronic control on the unit make and model #'s?

Glenn Harrison_2

I would look at the

electrode sensor assembly, and the burner head. These units have always been infamous for eating electode assemblies, and sometimes burning thru the burner screen. Otherwise, since this is a direct ignition burner, and the electrode/sensor assembly gets completely engulfed in the flame, I am not supprised that it would be real high. I have never personally tested it myself, never had a reason to.

Glenn Harrison_2

Tim

The information for that control is in all that stuff I sent you from my library to copy. The board is an OEM integrated control/ignition board made by Heatcraft for the Completeheat units. The ignition system is direct spark with the sensor and electrode as separate rods attached to the same assembly. The burner is a power burner. I unfortunately don't have my books in front of me, as I am home sick and my boss has my truck to run service calls while I am home.

rob

Basic Maintenance..

> electrode sensor assembly, and the burner head.

> These units have always been infamous for eating

> electode assemblies, and sometimes burning thru

> the burner screen. Otherwise, since this is a

> direct ignition burner, and the electrode/sensor

> assembly gets completely engulfed in the flame, I

> am not supprised that it would be real high. I

> have never personally tested it myself, never had

> a reason to.

rob

Basic Maintenance..

I was sent to do a PM on the unit. I read through the literature left a site. Manual said that PB was virtually maintenance free, so I paged my super. He said to inspect and check the ua, temp of water vs. setting, etc.
Found a condensate leak in the black tee/drain tee that is attached to the vessel with four studs and connects to the exhaust pipe. I had hoped it was the SS coupling that is used to connect the PVC exhaust, but after wrapping a wiper just below the cabinet the leak persists. It looks like a hairline crack in the fitting. BTW the original ua signal was 6.90 per tag on unit. CET yeilded no abnormal readings, guess burner should be ok. Also noticed a fault code: Diag1 blink,#2 off- thermistor failure. Reset 115V and fault cleared. Any other insight about this unit is helpful and appreciated. Thanks alot.

Edit: Check was visual, per I/O you can not pull burner without replacing gasket, so burner was not pulled. All visual checks, except for ua read in series with lead removed a board.

Unknown

Thanks Glen, I am sure you

have been a big help to Rob. Hope you are feeling better, nothing serious I hope?

Just a note about moisture and leaks around microamp sensors. It has been my experience that any excessive amounts of moisture cause major problems with sensors and their ability to sustain a good flame signal. I have not however seen any case that it caused high microamps, usually very low. I find that typically with Heatcraft boards a high microamp reading indicates an electrical feed over into the sensing circuit from the board and I usually replace the boards. Heatcraft boards are hard to come by, not sure if Lennox maintains a stock of replacements for them.

Glenn Harrison_2

I'll be alright Tim

Just a lovely winter cold, on top of being asthmatic, has knocked me on my butt for a couple of days.

The reason I bring up the electrode and moisture is i have seen multiple times on these units where a little water leaks into the burner chamber at the point where the electrode enters the chamber. The water then causes rapid coorosion of the electrode, at which point the spark can jump to the burner head and/ot the sensor instead of the ground rod. If this is happening I could see the flame signal being high possibly due to back feed from the spark circuit.

Lennox should have a stock of these boards, as it is a special board made just for the Complete Heat units. It incorporates inducer, ignition, water temperature control, diagnostics, and communications between the HM30 heating unit and the AM30 hydro air unit. I will admit that I wouldn't be suprised if Lennox makes parts for these units scarce since they have stopped making these units.

rob

Thank-you....

Tim and Glenn for sharing your knowledge. It is nice to know that we all can still learn and help one another here at the Wall. Thanks, Dan.

Glenn Harrison_2

Tis' my pleasure Rob.

We can always learn and share ideas and help each other on The Wall, even if some arguements or rants pop up along the way.

If I can provide further assistance with the Complete Heat unit, just let me know. I have had my fair share of experience (mostly BAD) with them.

Dennis

Oh, the Complete Heat!

I am a Lennox dealer, oh how I loved that Complete Heat. I loving installed many, following every nuiance of the installation manual.
I was repaid for my loving kindness with a whole slew of very irate high end customers.
I am a survior, this is my story.
All but one (the first unit) I installed has been replaced.
Some with free furnaces supplied by Lennox and some with the Polaris heater tagged as an HM61 Complete Heat. Even the Polaris units had problems (leaks).
Just about everything that could fail on these babies did.
I had a customer (on vacation of course) have the plastic drain cock on the bottom of the tank cracked off at the threads, his basement floor has never been cleaner, but the $1900 water bill was a bit too much to take. His venter went bad, the igniter went bad, the 006 bronze pump at the top of the tank looses it's impeller once every 6 months.
I think Lennox may have fixed this problem as the last replacement unit had a black plastic impeller maybe high temp.?
What is the real killer with these units is the customers loosing their hot water and heat, that cold shower really ticks em off.

The last hold out which as I mentioned is the first one I installed, is coming up on the last year of it's warranty and I can bet you it will fail in warranty and he will get a condensing furnace and high efficeincy heater for free from Lennox.

Now to your problem, if you are lucky the tank is leaking at the welds under the duct board insulation on top of the tank. There are several tank penetrations that are welded very close together this is where most of the leaks happen.
The water will run over to the low spot where the blower ignitor mess come together, and short the ignition at that point.
I have seen the spark arch right through the ignition wire over to the blower housing or to the sensor wire. I fold some rainbow gasket material over and stick on all sides of the ignition wire as a temporary solution so they can get a hot shower.
Changing the ignitor is probably the hardest thing you will ever do. The combustion blower is bolted over the ignitor assembly, who in the hell engineered this thing?.
If you are real lucky and don't break the new one while reinstalling the combustion blower assembly, you will be home free. These units where designed to be worked on by technicians with three miniture hands, remember to turn your job radio up real loud so the customer will not here you cursing.
The only thing I can ever remember working on that was worse than this thing was the York natural gas fired engine heating cooling system, I think it was called the Triathlon, either way I kicked that unit to the curb. Dumb idea York.

Glenn Harrison_2

Ah Dennis,

I worked for a Former Lennox Dealer myself, which is how I got involved with these myself. I read your post and felt your pain. I have been down all the scenarios you listed. I loved how I installed all the upgrades in older units, only to have the eyelets fail a few years later, probably from the tork applied removing and replacing the dip tubes. The best ones are when the weld fails in the Burner chamber and the burner goes under water, making the unit inoperable, and then of course it will take a few days to get a unit shipped in from Des Moines to Chicago. Those customers had a few choice words for Lennox, most of which are NOT repeatable in a public forum.

My condolences for having to work on the Triathlons. I never had the displeasure, but have heard a few stories that made me glad I didn't.

Thank goodness Lennox finally removed their heads from their posteriors, and stopped the madness with the Complete Heats. May they all rust in pieces!