EK System 2000 hot water suddenly too hot?
Hi.
I've got a system 2000 boiler and indirect hot water system that's about 5 years old. For reference:
- I have the setup serviced annually, but looking at the service guide, I'm not convinced the heat exchanger has been flushed during every service.
- I have hard water.
- I have a scale stopper installed and replace the cartridge annually.
- I replaced the hot water anode last year with a Corro-protec powered anode rod last year after my current one was on its last legs.
- I have verified the temperature setting on the hot water tank is at the lowest setting.
- The ball valve at the hot water circulator is wide open.
- Nothing in or around the system has been touched for the past few months.
Last week I noticed the hot water from all faucets was significantly hotter than normal. I have found posts discussing low hot water output, but not this reversed scenario. Is there any troubleshooting I can do to try and isolate the problem? I do most of all maintenance on my home myself, but will call in a professional if need be.
Side-note: My current HVAC tech is great, but is not very familiar with System 2000s, so I'd like to see if this is something I can handle myself before bringing him in. Unfortunately, my original (EK-familiar) installer is over an hour away from me. They also misdiagnosed my last issue and it was a long, frustrating battle to convince them to look elsewhere for the problem. In the end, my current HVAC tech came in, got on the phone with EK and figured out the correct issue, so I am reticent to call the original installers again for assistance.
My first guess is a restricted heat exchanger? I don't seem to have ball valves on all four corners of it, so if that's the next step then I'll leave it to the pros.
Thanks for the help!
Comments
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is there a thermostatic mix valve on the hot water?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Exactly my question. And, if there is, is it stuck? They can get stuck, though rarely. Is the cold water feed to that valve open?
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
I don't see any mixing valves in the boiler room. I've traced the hot water supply and there are no valves apparent.
See pictures below:
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Hi, I may be off the mark, but how is temperature in the tank sensed? If there is a brass well for the sensor, there is a chance it has been coated over with scale/hardness from the water by the action of the anode. I've seen this mechanism mess with sensor readings.
Yours, Larry
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Most likely the cause would be a restricted plate exchanger you should have about an 80 degree rise between the domestic in and the domestic out on the plate exchanger. You need to test this with the tank calling and the tank circulator running. if the temperature rise is over 100 you have a restricted plate if not then i would look at the aquastat
John Ringel
Senior Technical Support Specialist
Energy Kinetics0 -
@Larry: Attached is picture of the exterior of the Aquastat (I know this won't tell us anything, but took it just the same). When I replaced the anode last year, it was severely degraded and absolutely covered in scale. It was down to a thread at some points.
@John: I've had the hot water heater turned off for the past day by disconnecting the hot water call wire going into the Digital Manger. I reconnected the wire and, using an IR gun, measured the temperatures at several locations. These temperatures were taken after 5+ minutes of the boiler burner cycling on/off and the circulator running the entire time.
- The temperate for domestic in varied from 80-90 degree on the copper the last few inches before going into the heat exchanger.
- The temperature for domestic out varied from 130-140 degrees direction under the heater exchanger at the threads/nut and going down slightly from there. Measuring at the hot water tank copper inlet itself, I got a temperature of up to 150 at a very particular point of the nut securing this pipe on.
I took short videos of the measuring and will see if I can attach them here. The rise seems like, at most 70 degrees - going from 80 degrees (min) domestic in to 150 degrees (max) domestic out.
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Backflush the HX. It's in the manual.
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@HVACNUT I did that just before I took these temperature readings. I connected a hose to the outlet and ran it to my driveway before opening the valve. The flow was strong from the outset and I let it run for about 30 seconds. Is that enough?
I am going to leave the system running and see if that makes any difference.
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I am still measuring a temperature at my kitchen faucet (with instant digital thermometer) of 151 degrees. This is after a backflush of the domestic side of the heat exchanger.
@heatdoc1 What are your thoughts on my 70 degree differential on the domestic side, with 80 degrees being my domestic in?
If the issue is with the Aquastat for the hot water heater, do you have a part number for that? I've checked the PDF (https://energykinetics.com/wp-content/documents/hot-water-tanks/installer-manual-tanks.pdf) and I don't see it listed in the Hot Water Manual (replacement part list, hot water diagnostics section, drawings, etc.). The "Hot Water Systems" section on pages 28-30 mention a mounted tank thermostat and I see on page 31 under "Typical Indirect Water Heater Installation" it mentions a surface mount type Tank Aquastat. I am assuming the EK system also uses a surface mount aquastat? Is the APCOM WH9 (in my picture above) the actual thermostat and only part that would need to be replaced?
Are there any other tests I can perform to isolate things?Thanks everyone for the input and suggestions so far.
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Is that an EK tank or a standard electric water heater?
Is the light on for Hot Water at the Manager?
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Hi, It's a surface mount thermostat, so no brass well to get covered in scale. Another question along this line… is there a piece of insulation over the thermostat when the sheet metal cover is in place? If not, it isn't sensing tank temperature as well. Thermostats like that are notoriously inaccurate, so good insulation helps.
Yours, Larry
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@HVACNUT Yes, it's an EK tank. The light for the DHW thermostat on the Digital Manager turns on and calls for heat. It stays on while the system does its thing (burner and circulator go on, burner goes off, circulator stays on, burner goes on again when needed). After long enough, all lights go off and the system rests for a while. However this seems to happen after the hot water itself gets to too hot a temperature.
The domestic in is reading via IR around 80-85, the out measures 140-150 via IR gun and 151 with an instant digital at my kitchen sink on full hot.
I'm thinking it's worth replacing the Apcom WH9 to rule that out as the problem. It seems very easy to do and is only a $15 part…
Edit: I did not have my hot water faucet running during the IR tests, so I'm assuming that's why the domestic in wasn't dropping. I can repeat that test if necessary. However I still don't normally see 151 degree temps at my faucet…0 -
@Larry Weingarten Yes, not shown in my picture is the thick, white insulation moved out of the way. It is normally covered by the insulation and plate.
I think a swap of this part is an easy place to start. I've already backflushed my heat exchanger. If the thermostat swap doesn't work, then it sounds like further cleaning or replacement of the heat exchanger might be needed and that's when I'll call in a pro…0 -
Good morning, All. Not much left to cover here as everyone seems to have hit the nail on the head. I've attached a sheet that may help with trouble shooting. I would confirm with a clamp on thermometer, if you can, those temperatures. Based on the IF unit your using and the patina of the pipe the readings can vary. You'll also want to check out the boiler side and look for a 35 ° drop there under the same conditions of a tank re-heating. If your temperatures are outside the 70° rise and 35 ° drop, confirm your smart pump 006 is operational. Confirm the check valve is holding. At this time i would replace the plate exchanger.
It appears that the thermostat is turning on and off, but really that's all it's supposed to do. It doesn't control the temperature per say just confirms when the tank is totally hot. I didn't see a mixing valve in the pictures, but installation of one will give you more consistent hot water outlet temperatures.
If you need a service provider in your area you can call our Territory manager Brian Kiernan 570-872-6997 or the factory 908-735-2066.
Robert W.
Energy Kinetics
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There should be a date code on the tail end of the motor housing. 4 numbers at the " 6 o'clock" orientation.
Robert W.
Energy Kinetics
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@robertwagner The date code on the 006 is 12/19. Is that the old or newer version?
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It will have either an external spring check or an Internal one. IFC is the newer version and usually says so on the motor housing.
Robert W.
Energy Kinetics
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Robertw@
In the diagram you attached: the ball valve used for temperature adjustment is on the suction side of the pump. This is not a good idea as it likely to cause cavitation in the pump. I would of though the valve should be on the output side of the pump. Not as useful for isolating the pump!
John
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The domestic water pressure as well as the actual highest temperature achieved at that location will not allow it to cavitate. Its a very low-pressure pump and even dead headed it wouldn't cavitate.
Theres's fellas a lot smarter than me to fact check this but i think in this application with average water pressure you would need to hit somewhere around 250° to cavitate.
Robert W.
Energy Kinetics
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It is a good investment to have a listed thermostatic mixing valve on the tank. At least 4 States require a mixing valve on any DHW source.
An ASSE 1070 or dual listed 1017/1070 would limit the DHW to120 and fail cold.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
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I think all of the bases have been covered here. Based on the quick transition to hotter water, I would suspect that either a) something partially blocked the plate heat exchanger (maybe a piece of the degraded anode rod), or b) the check valve is not working and the circulator failed (gravity flow on the domestic side will heat the tank if the check valve is not working). For reference, we've found that IR guns are notoriously inaccurate for these types of diagnostics.
I know that @Robertw previously gave contact information for Brian Kiernan and our office for further support as well. Interested in your findings.
Thank you,
Roger
President
Energy Kinetics, Inc.
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All comments appreciated. I'll will surely be updating this thread as I begin to rule out possibilities and have a final answer.
True thanks to everyone for the help.
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One follow-up...
I do indeed have the IFC version of the circulator (006-BC7-1IFC). I see that I can replace the cartridge for about half the price of a new complete unit. Is this an acceptable way to go when also replacing the heat exchanger or is it best to bite the bullet and replace the entire circulator?
I understand that the circulator might not be the cause of the issue, but i'd rather get new parts in now while things are being worked on since we're approaching six years of operation.
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Update:
I stupidly left the hot water heater signal wire connected last night (I had been removing it after re-heating the tank for the past few days just to be safe), and this morning I found water streaming out of the hot water relief valve on the hot water tank. I don’t think it was going too long, but definitely several hours as there was condensation around the room due to the heat/humidity. Luckily I have a sandy hole in the foundation near the hot water tank, so there was no permanent damage.
I have reached out to my HVAC tech to come out as soon as possible. In the meantime, I have the boiler shut off as well as the water going into the tank. Shutting off the incoming water valve stopped the water output from the relief valve. My replacement thermostat is arriving today…
With this new info, is it easier to pinpoint a more definitive answer as to what has failed in my system? To me, it seems like the system isn't receiving a signal to stop making hot water when the hot water gets to the set temperature (which seems like it would point to the thermostat), however I'm certainly not an expert. Do we still think it's the heat exchanger at this point?0 -
Well seeing as how the unit didn't shut off the thermostat, and or the wire to it is definitely bad. I would have your tech perform all the steps listed in the document I attached. If he has any questions or trouble he can call the factory at 908-735-2066 and tech support will be happy to help him with any trouble shooting.
Robert W.
Energy Kinetics
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Re: infrared thermometers.. If you are using one to read temperatures, spray the pipe with flat black spray paint and it will read correctly. IR doesn't like shiny stuff.
Rick
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Another update:
I have replaced the lower aquastat. I set the unit to its lowest setting, which I believe is 110 degrees. I then powered the system back on. After 20 minutes, hot water was coming out of the tap at 120 degrees (via digital instant read thermometer). I let things sit powered on and the call for hot water remained on. After another 10 minutes I was measuring hot water at my kitchen tap at 140 degrees. I turned the system off at this point, thinking that maybe the tank needed time to heat soak for the aquastat to register the actual water temperature via the tank shell sensor. After waiting another 20 minutes, I turned the system back on and the call for hot water was instantly lit. I opened the tap and the water coming out was still almost 140 degrees.
I am ready to now replace the heat exchanger and circulator cartridge/IFC, however I don't understand why there's still a call for hot water even though:
- the aquastat is brand new
- the aquastat is set at 110 degrees
- the tank hot water is at least 140 and has been sitting for over half an hour
Am I missing something here?
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@magisimo If your wire is bad, this will give you a perpetual call for hot water as well. If your plate heat exchanger or the other items described in the attachment i sent you are bad, it may take longer than the normal 15 to 20 minutes to satisfy the call for hot water. When is the tech you called coming?
At this point i would have him call in to tech support while he is on site.
Robert W.
Energy Kinetics
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@Robertw The system was giving me 120+ degrees of hot water right around the 20 minute mark (after) being off for 36 hours, which seems like it's pretty close to target.
My tech is trying to get on-site tomorrow. I will have him call in. Anyone he should ask for in particular?
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