System 2000 EK1 DHW question

wlee

Last week I replaced by old Peerless OIl Boiler and indirect tank with a System 2000 EK1 with the storage tank for DHW. I have a question about the DHW temperature, as it seems it's much hotter at times than it should be. I am also in touch with the installer who is looking into it.

The DHW storage tank setting is at "A", the lowest setting, which according to the installer should be about 120 or so degrees. Here's what I observed so far...in the morning, after the system has been at rest all night, the DHW temperature is about 120-ish degrees, so no issue there. After a shower, I can see the circulator light lit on the energy manager, and the DHW zone is open. The burner is off. The EM says its "Purging to HW", and it continues to do so for some time until it turns off and closes the DHW zone. If I check the hot water temp again at this point, it's much hotter than before, over 136 degrees this morning. What I'm concerned about is if multiple people are lining up to take showers...the first one will be OK, but if another follows only a few minutes after the first, their HW temp could be as much as 15 degrees hotter. If I understand how the EK works, during the summer, with no zone calling for heat, any excess heat will be purged to the DHW storage tank. Apparently this results in raising the DHW temp regardless of the thermostat setting. Is it supposed to work that way?

szwedj

Thank you for your post, @wlee . We recommend that the tank should be heated to 140°F for sanitary purposes and for good hot water temperature quality. Without a hot water draw, it takes several days for the tank temperature to drop enough to signal the thermostat to replenish the hot water. Because replenished hot water flows into the top of the tank and cold makeup water flows into the bottom of the tank where the thermostat is located, the system is extremely responsive, so it seems odd that you would have 120°F water overnight. We do recommend a mixing valve where required by codes or if there is a concern about hot water temperatures. Please have your technician call us at 908 735-2066 so we can review your concerns.

Joe Szwed
Energy Kinetics

Jamie Hall

Not surprisingly, all of @szwedj comments above need to be heeded. I'll emphasize one, though.

If there isn't a mixing valve to control the temperature to the users, there needs to be one. Maybe code doesn't require it in your area, but it's for your safety and your family's. I'm not usually a fanatic about such things, but that's one of the few exceptions.

wlee

Closing the loop on this thread…the installer was out last week and installed a mixing valve. They also raised the temperature setting in the tank per the recommendations. It was a bit tight but they managed to put it in a place where I could get to it. All no charge. Apparently the valve is not required by code in our town so it wasn't part of the original bid/install. Anyway, they made it right, and so far all is working well, with consistent DHW temps throughout the day. Thanks @Jamie Hall and @szwedj for your suggestions.

Greening

Great - can you take a photo of the whole system? Thank you.

wlee

@Greening I posted photos of both the old boiler and the new EK1 at the bottom of this thread:

https://forum.heatinghelp.com/discussion/196945/help-with-new-hvac-and-oil-boiler