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Heat Timer EPU Issue: Shutting off during heating timer cycle too early

I have a Heat Timer EPU that shuts off the red light way too early in the heating cycle, right around 5 minutes no matter what the heating setting is set to. And the strange thing is that I have two of these controls that are doing the exact same thing at different buildings.

The problem is as such, whenever the yellow light comes on indicating that the condensate has returned and the heating cycle has started, the timing wheel spins to around 5 and then stops the boiler. However, what's strange is that if I manually start the heating cycle timing by spinning the wheel, even if by a little bit to say 1 minute, the red light will stay on until the specified time dictated by the heating adjustment letter.

I know these are old controls that aren't really supported anymore, but I wanted to see if anyone had any knowledge of where to start troubleshooting. I'm familiar with how to use a multimeter, but there's no schematics so it's hard to think of where to start troubleshooting or what part is acting up in this case. I already tested it by calibrating the outdoor sensor, changing the outdoor sensor and the condensate sensor, so I don't think it's any of those causing the problem. What could it be that this happens around the same time for two of the same boards at different locations?

Would appreciate any ideas or inputs. Thanks.


    EBEBRATT-Ed Member Posts: 13,456
    Sounds like you have done what you should. Strange they would both act up at the same time. If you have to replace them look at the Tekmar less $$$$$and work well
  • ScottSecor
    ScottSecor Member Posts: 681
    This may be a longshot and an unlikely fix since both panels are acting up at the same tome...
    I suggest pulling the panels so you can inspect the back of the panel. You are going to see the clock motor, switching relays, resistors, capacitors and many other electrical connections. We have repaired a few of these units by simply re-soldering connections that have failed over the years. What I'm getting at is look for a loose connection, might be a simple fix. Since your boards are in different buildings I suspect one of them was acting up before the second one, you just happen to notice it after the fact as you were paying more attention.

    As @EBEBRATT-Ed suggested, it is probably time to replace the controls. We switched to specifying and installing Tekmar from Heat Timer about fifteen or twenty years ago and have been pleased with the results.

    I have personally visited five larger apartment houses during the 2019 heating season that someone sold the owner a new remote control panel for their steam heating system. This new system would allow the owner to control the boiler/burner from his office or his cell phone. The system included an outdoor sensor and an indoor sensor installed in the lobby, there were no pipe sensors. We picked up the accounts in late November and were called in two or three times to each building before Christmas. All of the calls were no heat or a system leaks. On every visit, to every site the "remote" controls were in bypass mode (regardless of outdoor temperature, return temperature or steam pressure). On our last visit, before "firing" the customer for lack of maintenance, slow paying, only calling us (to bad neighborhoods) after hours on weekends, I decided to look into the remote control system. It looked like it was made in someone’s basement and it was actually designed for hot water and hot air systems. It appeared the company was already out of business and the customer support phone number was no longer in service. I believe the owner was paying a hefty monthly bill for this "heating system monitoring service." My point is, if you decide to replace your control boards, go with a reputable brand, not the fly-by-night companies that promise the world and don't deliver. Finally, I doubt a new control will last fifty years (they don't make them like they used to.
  • Steve_210
    Steve_210 Member Posts: 628
    We did used to have these rebuild, but stopped because they never lasted very long too many callbacks. for the most part now we replace with techmar 279
    Sometimes a EPUD
    Let me know where you’re located I may have a couple rebuilt laying around if you want to spend time on this.
  • Danny_G
    Danny_G Member Posts: 3
    @EBEBRATT-Ed and @Steve_210

    Exactly what I was thinking already, replacing the Heat Timers with the Tekmar 279. Cheaper and at the rate that these Heat Timers are going faulty, going to safe some more hassle in the future. Thanks for the offer Steve, I'm in NYC so there's a few rebuild options here, but as you said, too many of these going faulty to consider rebuilding again.


    Thanks for the input and you're probably right that it's coincidental that I just noticed both at the same time. I will double check the solder connections and if I don't find anything, time to change controls come next heating season. But adding on to your anecdote, I completely agree. In NYC, there are multiple companies offering these remote, higher tech, subscription based service for these heating controls. In my experience, it's just more failure points from all of the added sensors or in the control box itself, not as intuitive to navigate for the layman or the super, and unnecessary added costs. When there's not enough heat, as you stated, the first go to is putting those systems on bypass since adjustment is difficult.
    EBEBRATT-Ed Member Posts: 13,456
    @Danny_G Everyone seems to have good luck with Tekmar
  • Steve_210
    Steve_210 Member Posts: 628
    I am Also in NYC message me when you can
    I love the techmar 279 only thing is I would keep a sensor or two onsite return sensors seem to go bad after 12 to 18 months in my experience.
    Not a major deal it’s a universal 10k inexpensive sensor
  • Steve_210
    Steve_210 Member Posts: 628
    Sorry maybe it’s more like two years plus I don’t wanna be too critical I like the control As I say it’s an easy fix.