Energy Kinetics System 2000 Accel CS vs Resolute or Resolute RT

ceodice

Looking for opinions from anyone that has either of these units using natural gas, Also they claim nearly endless hot water. Has anyone run out of hot water?

RonnieJ

Hi ceodice, I have a System 2000, oil-fired, with an indirect 40 gallon tank. We are a family of five - the older "kids" take upwards of 30 minute showers (groan). When new, it would supply endless hot water. My system is roughly 26 years old - it still has the original H2O heat exchanger. We did have reduced performance about two years back - I replaced the storage tank (24 years old!) and acid flushed the heat exchanger - this essentially restored the performance. I probably need to replace the exchanger to get back to truly endless hot water.

The boiler has a brazed plate heat exchanger with a dedicated circulator on the domestic side. You can set the hydrostat (thermostat?) on the HW tank to a higher temperature to extend the delivery time if you are taking very hot showers. There is a ball-valve on the supply to the exchanger - this allows you to slightly slow the flow through the exchanger, so you are getting the maximum heat transfer from the process, if needed. I did this recently - but never had to prior.

Counter-intuitively, this allows the tank temperature to be maintained at a hotter level at the top where the supply is drawn off. This does not affect the supply volume - the water is circulated through the exchanger, and returned to the top of the storage tank. The dip tube is designed differently than a traditional HWH - heated water is released near the top of the tank, about a foot below the outlet. This means the hottest water is available for use - hence the near-infinity water supply.

I'm a homeowner - not a professional. I really like this system - it's been efficient and reliable. I don't believe the fuel type would have any effect - the burner is going to deliver the BTUs it's rated for.

Ron

SuperTech

@RonnieJ it sounds like you need to have a scale stopper installed for your plate heat exchanger. It's an Aqua Pure AP431. Energy Kinetics recommends this in installations where hard water is present, which is everywhere in my area. The scale stopper really takes care of the problem and keeps the hot water endless. I've never had anyone with an Energy Kinetics boiler complain of running out of hot water. Fantastic boilers in my opinion.

Roger

Thank you for your question @ceodice and for the insightful and positive comments from @RonnieJ and @SuperTech!

For hot water sizing, we recommend a plate heat exchanger with a storage tank that is sized for 2/3 of the largest use. For example a 120 gallon drain down tub would have an 80 gallon tank recommended. The ratings in gallons per hour are shown on the specs/brochure for each product. This information is typically adequate for nearly all residential applications. For commercial hot water applications or if multiple simultaneous showers with high flow shower heads are anticipated, please contact us or your heating professional for further information to ensure the hot water system is designed to meet your specific needs.

Regarding natural gas or propane applications, the Resolute RT uses a Carlin EZ Gas burner, which is a workhorse with notable qualities of easy service and a history of long term reliable and efficient performance. The Accel CS uses an industry standard negative pressure gas valve and an EBM fan, which are produced in the millions and have been very common in modulating condensing boilers for decades.

Best,
Roger

RonnieJ

Thanks @SuperTech - I just checked the local water quality report - and sure enough, it's moderately hard to hard. I'll check out your suggestion!

SuperTech

Also don't forget to back flush the plate heat exchanger as well. I always do that as a part of regular maintenance.

GTPaPi

Hi all, especially the pros and @Roger.  I stumbled upon this thread as I was searching for solutions to my hot water problem. I had a Resolute RT installed with the 40 gallon indirect tank last August and the installer has been troubleshooting the hot water running out too soon and not keeping up. He's been working  with EK customer service and this latest suggestion doesn't make much sense to me.  I thought I'd post it here to see if anyone has other suggestions. 
I have 4 heating zones and hot water so the 5 zone energy manager is what is hooked up now. They told us to upgrade that to the manager with 16 zones I think, just so we can get another zone to help with the hot water by controlling a zone valve on the return side of the boiler.  I guess it will close the return to the boiler from the heating zones to keep the boiler on to heat the hot water?  Does that sound right?  I am by no means a professional but have some understanding of what's happening in the system and the energy manager which is why this seems weird to me. 

Anyhow, what's happening is after 2 showers, the hot water runs out and it gets cold and it seems like the burner can't keep up.  We have felt that the hot water pipe going into the tank out of the exchanger is not that hot, we adjusted the ball valve b4 the circulator a little bit and it helped some but we still had the problem. It's well past the 11 o clock recommended. 

Any ideas welcome. Thanks so much. 

Roger

Thank you, @GTPaPi .
If you have large cast-iron radiation, and more than three zones, we might recommend a 15 zone manager to properly distribute the water through your heating system and control the production of hot water at the same time. I don’t have enough details on your job although that would make sense per your description.

For reference, we don’t recommend a position like 11 o’clock on the domestic ball valve, the setting is based on the temperature while hot water is flowing out of a fixture. The setup instructions are on our website. 
Please PM me with your contact information so I can get further details from our team and possibly from you as well.
Other than that, you should have tons of hot water with a Resolute RT (about 4x as much as gas water heater), so I would check the shower flow rates with a 5 gallon bucket to make sure we’re not missing anything. 

Best,
Roger