Trouble with an indirect

Unknown

Just curious....did they have you try pushing the sensor down in to a lower position? A far as the L7248 error code goes, that sounds like a rare bad control as you did exactlt what the Error Code 4 advises doing and it now fires fine. What model circulator do you have on this?

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

Scott04

We installed a Burnham MPO with an Amtrol TD 7Z indirect on Wed. Problems stated when, after bleeding the pump, the burner fired for about 30 seconds before loosing flame. Burner continued to run, but no oil! Traced it back to the combination control, was flashing error 4. Tested incoming power...120 volts. Tested power at B1... 20 volts! Replaced the control, and all was good!

Before I left, the indirect had shut down, and I had 120* water at the tap.

Next day, customer says not enough hot water! I found that the indirect was coming up to temp 5 mins. from a COLD start. After heater turned off, I again had 120* on tap. I shut off the cold inlet to the heater, and opened a hot faucet, I drained about 7 gals. of COLD water from the bottom of the heater. I had the return from the heater piped into my return manifold, which a Burnham rep had told me was ok, even though the instructions show it piped to the bottom of the boiler. I repiped the return, same results. I purged multiple times, same thing. I changed the control per Amtrols advice, same thing. I pulled the coil, checking the location of the sensor, as well as checking the dip tube for the cold water inlet. Everything was ok, everything that is except I have the SAME PROBLEM!

Anybody have any ideas?? Amtrol has no idea, and neither does Burnham! (I only contacted Burnham because they used to market the Amtrol WH series.)

If I can't get any ideas, I'll be installing a new heater Mon.

Thanks,

Scott

Unknown

Scott

How do you have the Amtrol wired to the MPO? The electronic high limit that the MPO comes with has no provision for wiring an indirect directly to it so I would assume you have an isolation relay. If that indirect has the Smart Control, the two sets of wires are not connected to a relay with off-on contacts. They work on a reduced voltage principle whereby there is still voltage flowing through but not enough to start a pump or burner. If that is what the indirect is equipped with they are not compatible with electronic boiler controls such as the R7184P and L7248. I would advise getting the dial type control for the Amtrol and wiring it to a multizone relay instead.The 20 volts you saw at B1 was probably what is trickling through the Smart Control. Let me know what you have there and we'll get it figured out quick.

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

Scott04

Glenn,

This Amtrol has the dial. It is hooked to a taco SR506 relay with the x-x hooked to the wires that go to TT on the boiler control.

Thanks,

Scott

Unknown

Tough one to call Scott

I would guess that if you verified 120 degrees at the sink , then the whole indirect is basically around the same temp . Being a cold start system , maybe the boiler is robbong the indirect of it's heat for those first few minutes after startup ? Does this happen in the morning when the boiler wasn't fired overnight ? You said it took only 5 mins to heat the tank , so I guess that might not be it .

Can you add a drain onto the hot of the indirect with a shutoff downstream , and hook a hose on to it to verify the tank is holding all the water at 120 ? Fill as many 5 gal buckets till the water ain't hot . At the least you can eliminate a cross connection as the culprit . It doesn't happen often around here , but it does happen .

I'm not familiar with Amtrol , does it have a dip tube on the cold inlet ?

Tony_23

How about

Running the IDWH at a higher temp and mixing it down ? Gives a more steady temp and acts like a bigger tank.

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Scott04

Glenn,

It's a Taco 007 circulator. The sensor goes into a well, and when I pulled the coil, I made sure the sensor went to the bottom of the well.(It has a comp. fitting on the tube to keep it properly positioned.)

It doesn't suprise me that the smart controlls give problems. When they first came out I had several complaints on them, to the point I told my supplier to get me the old style dial, or I would go elsewhere!

As far as the L7248 control goes, I agree that had nothing to do with the boiler, it's just one of those things that happen! This same job also has two radiators that nothing wil;l come out of the bleeder. I think the bleeders are bad, but there was a new floor put in these rooms, and the contractor wouldn't let me in to check! I'll find out that problem on Mon.! It's been one of those jobs!

BTW this was my first MPO, and I have to say, It's a great boiler! I can't wait for your new steamer to come out.

Thanks,

Scott

Scott04

Ron,

Right after the indirect is satisfied, I turned off the cold inlet, opened a hot water faucet to break the vacuum, and drained 7 gallons of cold water off of the bottom of the indirect. At that point, the water coming out the bottom was only luke warm. There is a dip tube on the inlet, which I have checked and found to be intact.

When I get cold water out of the faucet, it is cold coming out of the Amtrol as well. I only get about 10 gallons of hot water from the 40 gallon tank.

Tony,

If the tank was working properly, and I wasn't getting enough HW, your idea would be great. In this case though, the tank is not heating the full 40 gallons. This is a problem that I have to FIX, not mask by increasing the temp and mixing it!

Thanks for the replies,

Scott

Tony_23

10 gallons !

Guess I missed that part. That IS unacceptable.

I would try bypassing the stat and see if the whole tank heats up. If it does, new stat and maybe well. If it does and you still get only 10 gallons, make a dip tube out of copper. I've seen plastic ones get a hairline crack.

Of course, since it's new, Amtrol should make it right.

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Scott04

Tony,

The well is built in and goes down about 1 1/2'. I have tried a new thermostat with the same results. The cold water dip tube is also built in and is metal. I did check it and it seems ok. I don't think it's the tube since I can draw 7 gallons of cold water from the bottom of the tank right after the unit shuts down.

Thanks for the input,

Scott

Donny

stratification?

could that be what's happening in the indirect? would you consider a d.h.w.r. system if none is present. just a shot in the dark!

Tony_23

How about...

Reversing the flow thru the heating coil ? Not familiar with the internals of the top-down heaters, but maybe the well is surrounded by, or too close to the coil ? Could've been mislabeled.

Might be worth the 1/2 hour.

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Scott04

Donny,

It does seem as though stratification may be an issue here. The plumbing in this house is a mess, and a recirculating system would be a hard sell to this customer.

Tony,
Sorry, forgot to post that I had already tried that as well! The label on the heater is one way and the installation manual says the opposite!

The sensor runs next to the pipes going to the coil, and ends up about 2" above the coil.

Thanks again,

Scott

Tony_23

Well...

That sounds like a poor design to me.

SC the Amtrol and use the money for a good one

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hr

Are you saying

this is the new version with the coil inserted from the top ? And the thermostat well is 2" above the coil?

While you should not have to modify the factory design, perhaps try mounting an aquastat nead the bottom 1/3 of the tank for control???

I'm very surprised tha tank could warm up from a cold start in just 5 minutes. That doesn't sound right unless you have an awful lot of boiler hp to drive it.

A very small recirc pmp could also be used to mix the tank, but again this should not be necessary. Fairly easy to install that Grundfor comfort system as a retro fit DHW recirc system.

Contact ME, I think he installed a top/ down Amtrol in his home?

hot rod

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clammy

bad sensor

If the sensor is mounted ony 2 inches from the bottom of the tank and it's set for 120 i woulds believe that being at the bottom of the tank the top would be at a higher temp? I would recommend checking the outlet water temp with a good thermometer (digital) to verifie the water actual temp .I would also guess that the tank sensor is not sensing the temp correctly.Personally i stop using amtrol tanks about 4 or 5 years ago and would not use there product for a indirect nor would i use there smart control had promblems with there stuff years ago and clammy says no use no more end of story .By the way what size pipes did you run to the amtrol 1 or 3/4 and you where using a pump not a zone valve ?and what is your incoming water temp just curious on another note even though you stsated that a mixing valve and higher tank temp would only mask the promblem wheree i am located all indirects must be installed witha mixing valve it's code .try a new tank sensor and control for it and if the promblem still existes i would just replace it witha another unit .Peace and good luck clammy

Scott04

Hot Rod,

Yes, this is the newer version with the coil hanging down from the top.

I'm not sure how I could mount an aquastat lower in the tank!

I think the reason it warms up from cold start in five minutes is that it is only heating about 10 gallons of water, not the forty gallons that the tank holds!

This is the 5th or 6th top down that I have installed, and the first to give me any problems! I have installed 50+ of the standard model, with the only problem being the smart control. I used about five smart controlls and went back to the old dial!

I've had a few people here say that they have had problems with Amtrol. What were the problems? With the quality of water around here, the plastic tanks seem to be the only thing that holds up!

Thanks for the input,

Scott

hr

Sure sounds

like only the top portion of the tank is being heated. Either the t stat is not sensing correctly, or at the correct bottom location, or it only has a one wrap HX coil

Regardless, if all the piping and pump sizing to the boiler is correct then I would guess Amtrol would replace the tank.

You are sure the circ pump is operating? Actually removed it and checked the impeller and assured it spins when powered?

Also the delta t across the hx coil would indicate the amount of heat exchanged.

Keep looking, it's bound to be a simple problem, after all it's just heated water in a tank. If 6 others perform just fine, I highly doubt it is a design flaw.

hot rod

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Scott04

Hot Rod,

The thermostat is bottomed out, and I've tried a new one as well! The delta T is about 40* accross the HX. And the circulator is turning.

I guess the only thing left is try another tank. I can't imagine what the problem could be. My only worry is what if the new tank does the same thing??? I sure hope not!

Thanks for the advise,

Scott

hr

Isn't that coil removable

if you have tried everything else, yank the coil and look inside. Either the coil isn't heating the entire tank, the stat is turning off too early, or the tube that takes the cold to the bottom isn't??

Of course the hot and cold are in the correct taps?

hot rod

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Joe@buderus_2

L7248

Just a note about the new Honeywell electronic L7248/L7224 series controls. If the aquastat detects any power on B1 or B2 after burner shut down, the ERR4 will show up. After a few ERR4, it might go to ERR8. Once in ERR8, there is only one shot to reset this error code. The next ERR8 message and the aquastat will not reset. We have seen this with a direct vent Riello burner bleeding back slight voltage on the netural during post purge. The aquastat detects this voltage and "thinks" the burner is running away.

Scott04

I've pulled the coil, and everything looks like it should. coil goes down near the bottom of the tank, dip tube is intact, and the sensor well is straight and maintains the same distance from the coil pipes for the length of it. I've tried everything I could think of and have found nothing wrong, other than NO HOT WATER!

A very frustrating experience! If I don't find anything tommorrow, I'll swap out the heater and see what happens!

Thanks,

Scott

Scott04

Good to know!

On the control I had, the problem was the aquastat was only sending 20 volts to B1. For some reason the burner wouldn't run on that!

I'll be so glad when this job is done. The installation itself went well, but between the faulty control, the indirect not heating, and the radiators not bleeding, it rapidly turned into the job from hell.

Scott

Jerry_15

I've run into this kind of aggravation on long dry wells coming from the top with a sensor. (not sure of the sensor well on this model, don't use amtrol) A quick test is to pour a little water down and watch the gauge for a quicker response time. If it works, top it off with some mineral oil. KY jelly works good too if it happens to be sideways, and is easy to clean up; but then you probably already knew that. Heat transfer can be a pain. Good luck.

Scott04

Clammy,

The sensor is 2" above the coil, not 2" from the bottom. I have tested the water at a sink and it was 120* on a digital thermometer. I have replaced the aquastat, yet the problem persists.

I'll be changing out the tank mon.

I'm not sure of the incoming temp. but if you'd like I'll check it.

I know that the mixing valve is a good idea, but it's not a solution to this problem!

Scott

Scott04

If it was a heat transfer problem to the sensor, wouldn't that cause the water temp. to be too hot? When the unit shuts down the circulator, the temp at the sink is 120* (when set to 120*) if I raise the aquastat, the temp at the sink goes up as well, but the amount of hot water is still limited to about 10 gal. and I can still draw 7 gal. of cold water off the bottom of the tank!

Thanks,

Scott

Weezbo

is there any chance your tank has air Bound within

or that the recirc on demand system has no check valve ,or the anti scald valve has something stuck in it letting in way much cold water right past the mixer right straight back into the hot side of the supply line?

it may not be electrical.


i have not installed the top down twin coil maybe there is a flow devise of some sort ...maybe something along the lines of a monoflow insert ....or some physical thing locking the coil at random...forcing water past the cold side of the anti scald devise....

if you have a zone rather than a pump....maybe the boiler side is falling on its face ....not changing the flow signifigantly and what is happening is the water is really only doing some rather heavy ghost flowing through the indirects supply pipe

Scott04

Clammy,
I don't believe that the coil could be air bound. There is no recirc. system that I know of. The only thing would be if they have one of the Grundfos units at a sink somewheres. I plan on shuting off the HW at the unit and seeing if it makes a difference. I may also install a purge valve in the supply as well and try purging it with full pressure from a faucet.

The only other thought I have is that one of the windings in the coil is plugged and it's affecting the thermal flow of the water in the tank.

I'll know more by noon, and will post back with what I find.

Scott

ScottMP

Scott

I have been following this thread. I think you answered your own question, it can't be a winding or clogged coil or bad circ., as you would have different problems. Slow tranfer would give you heat but slow recovery.

I am on the side of a bad sensor but not sure how. have you ohm'd it out to check it ?

What about shutting of the grundfos re-circ before changing the tank ? Is it possible that it is installed in reverse ?

I am not an Amtrol user either but it may be a design problem and your the "first one to ever have this problem ".

Lets us know what you find.

Scott

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Bob Bona_4

just a dumb ? Scott

what is the domestic water pressure? If you're 75 lbs or over, you are blowing through that amtrol too fast..

Scott04

Ok,

I still don't know the cause, but we changed out the unit this morning and everything is working properly!

Now all I have to do is get Amtrol to honor the warranty. Shouldn't be much of a problem, but I'm sure I'll get nothing for the labor. Doesn't hurt to try though!

As to the radiators not bleeding, I was correct that the coin vents were bad. I changed them this morning and all is well.

WOW now they have heat and hot water! I have never had this many problems on one job before! (And I hope I never do again!)

Thanks for all the help,

Scott

Paul Fredricks_3

I hope you or Amtrol figures out what happened and lets us know. Glad all is back on track.

Joseph Kerr

Good to hear

Scott,
Glad to hear it work out, I was definitely scratching my head after our conversation on Thursday. I'm very curious on what the defect was in the tank itself to make it perform that way. Sometimes the easy jobs sure have a way of becoming not so easy!!!

JB_2

amtrol

scott- glad things worked out, after all your work. did you happen to measure the length of the sensor probe to make sure it was fully insurted in the well? had a problem like that years ago, copper well tube was faulty, not going in all the way, tank would heat fast,but only half way. good luck. jb

Unknown

Scott

It is always nice when we get to hear the final verdict in cases like this, even if you weren't able to find out why! It's great to hear that you are back up and running though. Thanks for following up Scott. We all appreciate it.

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

Scott04

If I get a cause from Amtrol, I'll let you all know what happened. Chances are I'll get a replacement unit and never hear another word though!

When I got the unit back to the shop, I pulled the coil and checked a few things, just out of curiosity. I hooked a hot water supply hose to the inlet of the coil to verify that both wraps of the coil got hot...they did. I hooked a hose to the domestic inlet and held my hand over the outlets on the dip tube to verify the tube didn't leak...it didn't. The coil is suspended about 2" from the bottom of the tank. The sensor is up about 1' from the bottom. I can see nothing wrong, yet it didn't work!

The replacement tank I put in was the one I had stolen the control from to try in this unit, so I can't even say it was possible that I had two defective controls.

I'll probably never find out the cause, and I hope it never happens again!

The worst part about it was that to save room in the basement, and make the boiler more servicable, we had tucked the Amtrol in the corner behind the boiler on the premise that we very seldom have any problems with them. It was accesible, but NOT ideal!

Scott

Scott04

Bob,
The water pressure runs between 30 - 50 lbs. Around here we have all wells.

Scott

Weezbo

that is good to hear *~/:)

spun in a new one and shes up and running.... maybe it was a sensor maybe it was a capillary tube the amtrols with the dial are like so not hold three buttons for a count of 8 while rotating in an easterly direction and hopping on one foot until the light reads eprom 121 turn the dial, it clicks it goes people really really like no hassle dials

Scott04

I see you've had experience with the "dumb control" as well! LOL

Scott