aquastats keep dying-newer buderus

Ray Landry_3

Interesting that buderus and honeywell step up and this guy doesn't respond. You know it's not a control problem, it's an install problem

Mike James

Buderus Aquastats keep dying--is this why?

hello!

I have a buderus hot water boiler thats about 1-1/2 yrs old. It keeps eating expensive aquastats.

I'm arguing that the installers need to solve this problem because buderus isn't backing the warranty anymore, so its out of my pocket. We're on our fourth Honeywell L8148E aquastat.

I have two questions:
1) the installers say this model of aquastat is a lemon (I HAVE seen some comments agreeing with this on the web).

They want to replace it with a L8148J model. That would disable the stack damper (no builtin plug for it). Not really a big deal to me (I know it doesnt make much effic. difference, especially since it's standing pilot). If it IS true the "E" is a lemon then maybe that's a solution. But in a sense I'm not getting what I paid for, and also the "J" could limit future zone expansion (just one zone right now).

2)
The installers (yes, they were licensed) did a totally sloppy job (I've seen evidence of this over and over) and I unfortunately don't trust them anymore. One of the reasons I doubt their solution.

One of things they've never bothered to do is use the green ground connection screw on the aquastat case. They say it doesn't matter.

I've been thinking about this and if it could be the source of the problem. IS that possible? What do you folks do to ground aquastats, if it's even necessary?

In a way, I would think the entire boiler is grounded through its connection to the cold (feed) water pipe. So the aquastat is sort of grounded by its bonding to the boiler chassis.

It's a 24V thermostat, by the way, with 120VAC power coming to the aquastat from a switchbox. The wiring from the switchbox is two seperate conductors, which run through a conduit *but stop without being bonded to the boiler or aquastat case*. Basically, the insulated wires come out the conduit and then just lead into the knockout of the aquastat.

I hope what I'm driving at makes sense. I don't know what Honeywell requires for aquastat grounding (I could only find generic info on their website) and Buderus has been of no help (since the 1 yr warranty is up).

So, I've got to figure this out before it happens again. I'm scared of losing heat in cold weather, and the installers have proven unreliable in emergencies.

It did pass city inspection, but that was a pretty cursory deal. The electrical inspector didnt even pull the cover off the boiler to look inside. I think all he cared about was a shutoff.

Any help is sincerely appreciated...

mike

Al Letellier_9

dying aquastat

What does Honeywell say about all of this? I don't know where you are, but I get nothing but great service and problem solving (not that I've had a lot of them) from our local Honeywell people. I'm sure Bill will jump in on this one. What is the installation like? Is it in a confined space and ultra warm? Grounding the case is required by electrical code and if connected with greenfield or metal tubing, it needs to be less than 6 feet from a bond, but otherwise grounding shouldn't be an issue with this control. How is it dying? What is happening? Are you sure it's the control?

Noel

one question

Is there a 24 volt low water cut off wired onto that boiler?

Noel

Mike James

water cutoff=no

no, there isn't. Its hot water by the way (I thought cut-offs were usually on steam?)

Norm Harvey

Can you post some pictures?

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Mike James

Hello Al, thanks for the reply.

In answer to your questions:

Well, as a consumer not a pro, I got kind of passed around honeywell and got nowhere.

The installation is not a confined space (just a basement).

I'm not sure how to describe how they are dying.
Essentially it's a no-fire situation. There's power to the the aquastat but the burner valve won't open. I typically do hear relay chatter before the aquastats die.

The thing is, its such a simple install. The pump is wired to run constantly, so it doesnt start or stop that, and it opens the damper, but setting that to manual (permanent open) makes no difference. Even with that permanently swicthed to manual two aquastats have pooped out.

I'd say it's clearly the aquastat because replacing has fixed the problem every time, and there isn't much else to the system. No EI, no zones, no pump, no nothing.

My thinking was that some sort of power quality issue was killing them. At 200$ a piece this has to stop somehow...

Unknown

You're right

Although at least 12 states require them on water boilers, too.

Some of the 24 volt water type LWCOs eat transformers. Disconnect them, and the problem ceases.

Given a choice, always use the line voltage LWCO.

Noel

Al Corelli_2

Have you checked...

The incoming voltage?
The output voltage from the transformer?
The polarity of the incoming circuit?

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Mike James

voltage checks=OK

YA, all that was checked along time ago--besides, I would think if there was a problem in that regards they wouldn't last the 3-4 months that they do before dying.

Anyhow-
Incoming AC and polarity fine, transformer normal. There's never any indication of problems until one day the aquastat is just dead. Thats why Im trying to determine if grounding is relevent.

Absolutely normal utility AC power fluctuations there's no reason to think that power quality is an issue in general.

Something else is killing them...

Michael Welch

AC Power

Do not always assume that the incoming AC power is consistant. We had a job once that we were having problems with the controler. We borrowed a power monitor from a local town power company that we do work for and hooked it to the panel and found that there were times with extreme voltage drop off down as low as 90 volts and spikes as high as 130 volts in a 5 day period.

Pat_11

L8148E

I wouldn't say they are a lemon, but I've seen my fair share of problems with the vent damper molex connector on the board. Jiggle it and it works and then it doesn't. Only fix replace control. Good luck.

BillW@honeywell

\"Failing\" Aquastats

Please email me the following information.
A. Where are you located?
B. Name & Phone number of the installer/distributor involved
C. Tell me if any of these controls have been saved so I can have them sent to be tested.
D. Model # of the Boiler.

Thank you in advance.

Joe@buderus_2

Buderus of no help

Did the contractor call us or was it the homeowner? Not saying that we would not want to talk with a homeowner, but trouble shooting an aqaustat with a homeowner is not a usual course of action for us. If the relay "chatters" it's usually caused by the 24 volts "shorting". Check the flame roll switch, block vent switch, gas valve ground, vent damper wiring and if anything is wired into the low voltage (power vent, fresh air fan, etc...) Incoming voltage should also be monitored like mentioned in previous post. If Honeywell can provide any input please let us know.

Ray Landry_3

Interesting that buderus and honeywell step up and this guy doesn't respond. You know it's not a control problem, it's an install problem

JimH

i agree with hvac

this sounds more like an installation set-up problem than a defective control issue. my suggestion would be to call in an independant service company and explain the situation. let them understand that they need to send out their most experienced tech. because it has been an ongoing problem that is getting very expensive. if they find that the problem is installation related, contact the installer and have him give you a check for re-imbursement of the cost of the controls and the service related costs. if they refuse, you may have to take legal actions. hopefully, it doesn't have to get to that point.