Boiler Mate indirect water heater


Old 05-10-10, 11:20 AM
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I also had the same problem so after reading the posts here I called Tech service (401-535-1216) and spoke with Ray. He was very helpful and is sending a new part to me free of charge. Thanks to everyone that shared their info was very helpful!
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Old 05-23-10, 04:34 AM
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Fixing the darn buzzer.

I had all the same things: It started buzzing. After two months it died. I have studied the two threads here and found little about how to actually repair the buzz prone Smart Control. I studied mine, figured out what is going on, and effected a beautiful solution to the problem that costs nothing.

The ironic thing is that once the hot water heater unit is installed, the powering of the Smart Control is fixed for all time. It is either 120 Volts AC, or 24 Volts AC. Because of special circuits, the Smart Control will operate on either 120 or 24 Volt power. This accommodation is automatic. The entire problem is caused by the special dual voltage automatic circuits, even though they are not needed once the heater is installed with one voltage or the other.

The sole benefit of the special dual voltage design is for the maker and seller of the hot water heater, not for the end user. Because the heater will operate either way, it is not necessary to stock more types of heaters in the warehouse. Here is how those special circuits work:

The main part of the Smart Control has a power supply designed to operate off of 24 Volts AC. It consists of a full wave bridge rectifier, followed by a 220 uF 50 Volt filter capacitor. The input to this power supply is connected to the swingers of a double pole, double throw relay. The normally closed contacts of this relay are connected to the power input terminals (black and white wires) for the Smart Control main circuit board. Thus, if 24 VAC is fed to the board, it will flow through the normally closed contacts directly to the power supply (the relay is not energized.)

There is a small 120V/24V step-down transformer with the primary winding connected to the power input terminals (black and white wires) and the secondary winding connected to the normally open contacts of the relay. In the case that the board is fed with 120 VAC, this relay operates to switch the power feed to the power supply off of the power input terminals (black and white wires) and on to the 24V secondary winding of the transformer.

The relay coil is fed by the board power input terminals (black and white wires) via a rectifier diode and a small 4.7 uF filter capacitor. The resulting DC output voltage (across the 4.7 uF capacitor) is not enough to pull in the relay with 24 VAC, but is more then enough to robustly pull in the relay with 120 VAC. When the relay pulls in, the 24 VAC transformer secondary output takes over the powering of the power supply.

The failure mode is that the 4.7 uF capacitor develops an internal open circuit condition which removes its ability to filter the voltage pulses into a steady DC to operate the relay coil. When this happens, the relay starts buzzing at 60 times per second, back and forth. Eventually, this causes a mechanical failure. The movement of the relay armature back and forth "wears out" the moving parts. The relay does not "burn up."

This silly circuit can be removed. Remember, once the water heater is installed, the operating voltage for the Smart Control is fixed at either 120 VAC or 24 VAC. There will never be any need for this circuit. In my case, the control was powered by 120 VAC.

All that is needed is to remove the relay, and the 4.7 uF capacitor, and then install two jumpers on the relay solder pads.

Removing the relay is very difficult because all of the eight solder connections must be unsoldered at the same time. The right way to do this is with a solder sucker. This is a tool that uses a spring loaded piston to generate a high vacuum that sucks the solder away from the connection, one connection at a time. After each suck, you re-**** the tool and proceed to the next connection. You can purchase a solder sucker at a store that sells electronics tools.

The relay should be removed, because if it has broken parts internally due to long buzzing, it could have a short that could cause problems. The capacitor is not needed and it might also cause a problem.

To locate the relay and capacitor, look over in the corner of the board where the power input terminals (black and white wires) are located. The lone (not the other two that are laid out side by side like the coffins for a man and wife) relay is the one you want to remove, along with the 4.7 uF capacitor which is right next to the relay. It is a little cylinder about 9/16 inch high and 3/16 inch diameter.

Once the relay and capacitor are removed, install two jumpers on the solder pads on the circuit board (where the relay used to be) as follows:

Look at the pad pattern so that the group of six pads is at the top, and the group of two pads are at the bottom. Your viewpoint is from the component side of the board. The new jumpers are inserted from the component side, and soldered on the "circuit side" of the board. Start at the bottom left pad. This is pad 1. Go up to the next pad (the lowest in the group of three. This is pad 2. Go up to the next pad (center of the group of three. This is pad 3. Go up to the top left pad. This is pad 4. Go across to the top right pad. This is pad 5. Go down to the next pad. this is pad 6. Go down to the next pad. This is pad 7. Now drop to the bottom right pad. This is pad 8.

Pad 1 coil
Pad 2 NC contact set 1
Pad 3 Swinger contact set 1
Pad 4 NO contact set 1
Pad 5 NO contact set 2
Pad 6 Swinger contact set 2
Pad 7 NC contact set set 2
Pad 8 coil

120 VAC jumpers:
Jumper 1 from pad 3 to pad 4
Jumper 2 from pad 5 to pad 6

24 VAC jumpers:
Jumper 1 from pad 2 to pad 3
Jumper 2 from pad 6 to pad 7

When I finished this modification, I reinstalled my Smart Controller and it worked flawlessly! My hot water was back, and I had not spent one cent!

Good luck!
Old 06-03-10, 02:22 PM
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Amtrol Indirect Water Heater Problems

I have install a lot of indirect water heaters for customers. As far as I am concerened the best on the market is made by Buderus, I hardly ever have problems with them. As far as replacing an indirect with a regular electric tank it is cheaper but you will never get the quantity of hot water out of one that you do with an indirect if it correctly installed. I have also had bad luck with Weil McLain indirects they tend to leak inside the thermostat well. Also somoene said somethhing about no oil fired instantaneous water heaters being avaliable..and indirect heater is NOT instantaneous, they just recover very quicky. Instantaneous heater do not store any hot water as they make it as you use it and there again you will be limited on how many gallons per minute you is decieving to say they give you unlimited hot water. They will as long as you stay within the GPM draw rating, the entering water temp aslo has an effect on thier capacity.
Old 10-25-10, 05:39 AM
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Amtrol Canada vs. Amtrol US - The Smart Controller Saga

First, thanks to everyone on this thread. You saved me $200 (plus installation) by correctly diagnosing the problem with my WH7L and Amtrol Smart Controller. Now, for some words of warning.

If you call Amtrol Canada you will likely get a very grouchy individual who was 1) rude to my wife and 2) very little help. I called back and got the number to tech support in the US (1-800-736-1149 x444) where I spoke with John. After reviewing the symptoms of the unit (buzzing noise and LED display that faded on and off) and the age of the unit (installed in 2005) he told me he'd send a unit to us today. The downside, of course, is that it is coming by pack mule from the US to Canada, so I shouldn't expect it any time soon. As others have reported, John was an absolute delight to deal with and should be nominated for customer service of the year, IMO.

Quick question: What dangers do I have running my oil fired furnace for hot water and heating while waiting for the part to arrive? It seems to me that manual warns of over-heating and damage to the hot water tank.

Again, thanks to all for sharing your detailed problem descriptions and resolutions.
Old 10-25-10, 06:00 AM
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No problem

There should not be a problem with your boiler while the indirect is out of service. It is more likely that you would have no hot water until you get the new control. Either way, your boilers limit controller will protect the boiler.

Old 11-07-10, 11:32 AM
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I took the advice of ghavfam and replaced the 4.7 ufd 50V capacitor and all is well! I am not convinced it is a long term fix, however. There is a power resistor right next to the capacitor that looks like it gets very hot and probably causes the capacitor to fail. I will try to get a replacement controller, hopefully they have redesigned the board.
Old 12-12-10, 08:35 AM
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Thumbs up Little Mikie saves the day!

It's Saturday afternoon and I started hearing the buzzing. I took the Smart Control out of the 6 year old WH-7L. I found the relay that was making the noise and touched it carefully to confirm that is where the vibration was occurring. While touching it, the buzzing faded and then stopped. I was thinking "That was easy" until I noted that the front display panel was now dark. With little warning the unit had failed on me. First thing I did was go to this website. I was pleased (yet disappointed) to find so many other entries regarding this problem. I read through all the postings but was discouraged to find that my only real solution was to try and find a replacement unit.

Being a Saturday, I searched within 100 mile radius of my home for a plumbing supply parts store that was still open and found none. I dreaded the thought of telling my wife she wouldn't have hot water until early in the week. I found near the end of the postings (as of this date anyway) the one by Little Mikie on 5/23/10.

What did I have to lose? I could not get another unit, Amtrol was closed for the weekend, and I was out of hot water. I followed the directions and removed the relay and the capacitor from the circuit board. I installed the 2 jumpers according to the instructions (mine was a 120v). I put everything back into the "box" and holding my breath, threw the circuit breaker to restore power to the unit.

VOILA! IT WORKS! My cost to repair, about $5 for a "solder sucker" from local Radio Shack store. My only challenge was the removal of the Relay. Even after removing as much of the solder from the 8 pins as I could, I could not get the relay to come away from the circuit board. I ended up (very carefully) breaking the relay plastic housing apart with some needle nose pliers until I was able to get down to the circuit board. Then I was able to gently pull the pins, one at a time, from the component side of the board while applying the soldering iron to the circuit side. I simply snipped the leads at the base of the capacitor to remove it.

Little Mikie... I hope some day you will have the ability to see this note of thanks for taking the time to so completely and accurately explaining the steps you took. You not only saved me a couple hundred dollars (just before Christmas) but gave my family back the luxury of hot water (and my wife thinks I am pretty talented).
Old 12-12-10, 03:21 PM
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Controler works ok, but think the internal thermtrol needs replacing

So my issues have been this:

WP7P Amtrol 41 gal unit.

Internal tank temp shows 125, which is the set point. Water at the tap is COLD. SO i increased the set point to 140, which fired up the circulator and heated the water <yea> That was yesterday. Today the internal tank temp is 160. Cold again at the tap. The controller set point max is 150, so Im stuck. Thinking of jumping the circulator on a toggle, so my 9 months preggo wife can shower.

I found the temp sensor online for 27.00, Can have it by Tuesday overnight ship. Do I have to drain the tank to replace it, or is it in its own casing.

Does this even sound like the problem, or should I try and get a new control unit. I have the old one so thinking that repair is eminent. Does the replacement come with a new thermistor?

ANy help would be great..

Chris Z
Old 01-18-11, 05:54 PM
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Cool Amtrol Smart Control Fix

Wanted to post a Public Thank You To ISHAVE

I went to radio shack purchased a 24 V wired it to Black and White Wire
And Bingo. I worked . I buzzes a little bit . I think i will directly wire the replacement smart Control utilizing your method thank you thank you thank you
Old 06-27-11, 07:56 AM
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smart controller for BM WH7C

Not sure that "smart" is the right word for this controller. Mine went out again on Saturday night leaving me with a disgruntled wife for the weekend, wasn't going to pay out over $400 before at least calling Amtrol on Monday. Just got done speaking with Ray at tech support and cannot speak highly enough of him. He looked up my controller from the serial number and saw that it was a 2006 model. He offered to send me a new one (the ones since 2008 are supposedly bullet proof) no charge.
He also asked me to have a professional available for the installation.
Thanks Amtrol.
Old 11-11-11, 04:50 PM
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Just fix it

I have an amtrol WH-7L which is about 5 years old. My controller hadbeen buzzing over the last 4 weeks and today it decided not to work. When I exposed and re-energized the circuit card one of the relays began to hum very loud and I noticed that the larger resistor near the transformer was glowing read. When I called Amtrol to get a replacement they told me that I needed to pay $250 for a new one which is BS. This is a fire hazard and they should be replacing it for free. Not to mention the $250 is very overly priced. So the bottom line is amtrol should be replacing this part free of charge because it was poorly designed. I've been messing around with this thing for only a day and I'm trying to come up with my own fix. Personally I think that my issue is with the relay near the transformer. I believe that it has failed and in the process it may have damaged some of the other passive components. The relay is made by a company called dotpro Corp and has PN DP7715-2C-24D-151. I believe that dotpro is out of business but I may have found an alternate part made by a company called OMRON with PN G2RL-24-24DC ($3.20 ea). This should be an equivalent replacement to whats already there.

In addition to this the capacitor that may have been fried is a 4.7uf capacitor that is available from radioshack ($1.5). In case you need it the transformer PN is ST3-24B17 ($4.19) but unfortunately there is a min order of 40 and in some cases 80 pcs. Everything mentions should be available from companies like Mouser, digikey, and newark electronics.

Amtrol should smarten up and replace these controllers for free since they can easily be repaired. Again I'm just getting into this but I happen to be an pissed off electrical engineer who is determined to find a better solution then buying a new one from amtrol.

Removing the relay or transformer will be tricky but can be done with a good soldering iron, some solder wick and flux.
Old 06-17-12, 05:26 PM
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A few days ago I was in the basement checking up on things and noticed the Amtrol control buzzing away. After diving into it I discovered, like many of you, that the thing buzzing was a relay. Hearing the frequency of that buzz made me think 60 Hz. And that's when I starting thinking capacitors, since they generally filter out the voltage swings.

That's when I dug into this web site looking for some info. You guys are the best. Thanks for describing the problems and solutions. After inspecting my board I noticed that one of the ceramic resistors was leaning right up against the capacitor C3. The heat probably killed it. Surprised it lasted 4 years!

The local electronics store only carried 35v versions of this capacitor, so I had to head off the the big electrical supply store near Boston. They had the right capacitor in the right voltage plus a higher temperature rating. After removing the old one and then soldering in the new one the control works like new. Awesome!

BTW - I also bent the leads on both resistors R4 & R15 to keep them from touching anything. Look at the attached photo and sketch.... I hope they load OK. The resistor R4 is the one near the capacitor C3. But resistor R15 was also leaning up against the plastic connector for the wire harness and had melted the edge of it. So, check yours before putting it all back together.

Thanks again everyone.
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