Hello All,

I've been having an ongoing problem with my Tekmar House Control 371. Well over a year ago my oil company, whom I have a service contract with, replaced a shorted low water cutoff switch and wired it incorrectly. The boiler ran continuously immediately afterward and about an hour later, after they'd left, the safety valve blew forcefully spraying antifreeze everywhere. The problems caused by that are a whole other story, but after the fire department left the oil company techs came by to try and fix the problem. They hadn't realized that they wired the low water cutoff incorrectly so tried to find a problem elsewhere. Not thoroughly understanding our Buderus/Tekmar radiant plus radiator system, even though they've worked on it several times, they called Tekmar to help get a diagnosis. Tekmar's rep told them that contacts in the House Control 371 must be fused, forcing the boiler to continuously run. Since the units are no longer made, I was told that the 371 had to be sent to be rebuilt,at my large expense.

We were without heat or hot water for the 12 weeks it took for them to rebuild it. The oil company installed the new unit and the same problem occurred with the boiler running continuously. The tech did some investigating and found that the low water cut off switch had been wired incorrectly, causing the problem. Not realizing that it was his own coworkers that had done that, or that the low water cutoff switch had even been replaced by them (this was a different tech then had been sent previously), he told me "someone connected your low water cutoff switch wrong". Of course, we suspected that all along. It was just too much of a coincidence. So they hooked it up properly, we set the 371 to UnOccupied, and left for a couple weeks.

When we returned we found that the 371 had reset itself to Occupied and was heating the house fully. We never had this problem before it was rebuilt. It worked fine, always. I notified the oil company's service manager, who'd apparently been in the dark about this until now, and he visited personally with his finest tech. They set about replacing or tuning up anything they could think of. They replaced the antifreeze, the outside temp. sensor, gaskets, etc. but we still had the problem. They contacted the regional Tekmar rep from Lowell, Mass. who sent their finest man out (to Union, ME where the house is) this past June. He didn't seem all that knowledgeable to me but said he was going to be right on top of this so that it was fixed before the cold weather set in, and proposed that all the house RTUs be replaced. He explained that a bad RTU signal could cause the 371 to switch from UnOccupied to Occupied. Makes no sense to me, but the oil company went ahead and did that. That didn't work.

He dragged his feet for the next 2 months sending only brief cryptic responses to the oil co. service manager (whom I kept contacting) but not committing to anything else. I proposed we have the Maine AG arbitrate, or the BBB, or small claims court, and he then offered to install an external timer (or maybe switch, I don't recall - both were mentioned and I wasn't quite following him at the time). Instead of the timer, a simple switch was wired between terminals 13 and 14 on the 371 (I've learned a bit about it since) which either sets it to Occupied or UnOccupied. It bypasses and renders useless the internal timer (which I don't think he'd ever actually tested or identified as the cause of the problem) that allowed me to set a specific time frame each day for the UnOccupied period (with or without Optimum Start). Now it's either always in Occupied mode or always in UnOccupied mode.

That switch was just installed last week so we haven't been able to determine how effective it will be at curing the problem. It seemed to work for the brief time we were there, though. This is our second home, soon to be primary, and are away again right now.

The installer of this system has been in a serious car accident and, sadly, suffered a brain injury and is unable to help at all.

The symptom may have been eliminated, but the problem still exists. It will reset from UnOccupied to Occupied by itself at random times, eg. I've seen it reset in as little as 3 hours or as long as a month afterward. Occasionally when returning after a month away it may not have reset at all but is still in Unoccupied mode as it should be. Can anyone offer any ideas?

Thank you very much,

Cliff

This message has been edited. Last edited by: NewEnglandCliff,

Hi Cliff,

on the 371, when you hit the 'start' button to put it in unoccupied mode, the default is for it to run unoccupied for as long as the dial next to the start button is set for, and then flip back... every day... starting at the time you first hit the button. This is for daily setbacks, so if you, for instance, wanted a nighttime setback, you'd have to wait until your desired setback time, and then initiate an "unoccupied" event with a desired duration on the dial, say 8 hours. then every day at that time, for 8 hours, the system would run in setback.

This is what passed for setback programming prior to digital controls!

The dial must be set to "24 hr" to avoid flipping back to "occupied" mode again. If that is the case, you should not see the "timer active" light illuminate, and you have to hit the button to get out of unoccupied mode again.

If it was set to "24hr" and it STILL flipped back to occupied mode, then you have a problem, and an external switch may fix that. we have, in the past, wired phone switches to the external contact for unoccupied demands, so you could call the house and flip it from occ to unocc remotely, for instance. You could also use timers or anything you like to do the job remotely.

but if I had to wager, my first guess would be that when your 371 was fixed, it shipped back with a time on the dial other than 24hr, and no one has noticed.

that is a blind guess though, of course. I hope it helps!

Hi Rob,

Thank you very much. I should've mentioned that the timer has been set to "24 hr". We understand all you said regarding that. One thing that works differently though, is that when in 24 hr UnOccupied the timer light is actually on. This is true now and it was so before it was rebuilt. Then when we hit the Start button the timer light goes out and the Occupied light lights (and the UnOccupied light goes out). A strange thing that happens when the timer resets to Occupied by itself while in 24 hr UnOccupied is that the timer light remains lit.

It'd be nice if we had a hard phone line since it takes so long for the house to heat up when we arrive and we could turn it on early. We don't though. No internet service either. It's available, but we don't want to an an extra bill yet. A programmable timer would be nice if we ever knew the next time we'd be up, but we usually don't. We do have a radio transceiver with battery backup that sends signals to our security company. Is that something we could use to remotely fire up the boiler?

I see you're in Gardiner - that's close to Union. We drive through there all the time on the way to the house. We're going to need someone when we make the additions we're planning. Someone who actually understands this system like you do. Looking into geothermal, as well, and maybe solar or wind power.

Cliff

if the radio transceiver can RECEIVE signals,and close a contact, it might be usable. but other than that, without phone or internet your options are certainly limited.

I'm pretty sure the external contact has priority over the timer. But if not, you should be able to turn off the timer entirely in your case and just use the external switch for setback.

but you shouldn't *have* to, it should work, of course. it's a little strange that it stopped working AFTER it was fixed.

My oil company is offering to install a tekmar 033 timer in place of the Occ/UnOcc switch they've recently installed. This is a tekmarNet4 timer, but my house control is the older tekmar 371, not part of the tekmarNet4 line. Will this work? The original optional timer for my system was the tekmar 031 which is no longer made. I've read that the replacement is the tekmar 032 timer. Any suggestion?

Thanks,

Cliff

it'll work, you just won't get the teknet 4 communication features (which you don't have anyway).

Great, so this will allow, say, a nightime setback and then I can program it when to kick in again in the morning? I'm not sure how effective this would be with my radiant floor heating, but at least it wouldn't be heating my DHW each night. Are you hooked up with any boiler contractors in the Union area who have top knowledge of Buderus and Tekmar plus radiant (unless you do that)? I'm going to need one for service and when we'll be adding additions to the house, plus the separate proposed barn. The oil company is really trying hard but aren't really familiar with this equipment.

Night set back is a little tricky with radiant. I’ve found that a lot depends on the mass of the floor and the area. In my case, I have a lot of high mass tile floor in the middle of my rancher. My night set back for the tile area starts 2 to 3 hours before going to bed and starts one hour before we get up. We also have nine zones/thermostats so we can program each area set back differently according to its floor type, location and use.

with tekmar, setback works better because it will raise your system water temperature to pay "catch up" faster.
however, one thing I think you won't get with the timer external to the 371 is "optimum start/stop". the 371 has that, I think, which means if you tell it to come out of setback after 8 hours, it will attempt to BE occupied temp at the end of the setback period, instead of waiting until the end of the period to start catching up.

so you might need to play with the schedule to find the one that works for you. that said, I generally only recommend shallow setbacks if setbacks are used with radiant.

feel free to email me to discuss other stuff if you like. I would prefer not to talk business on the board.

OK. The only tekmar timer I know of that has the optimum start is the tekmar timer 031, but they stopped making that. Maybe they had issues with it.

The tekamr 033 timer has been installed and seems to be working. It actually has to be installed in parallel with the Occ/UnOcc switch also externally installed. They are used together and disable the internal timer of the 371.

I think I've discovered the reason we've been having the problems described above, though. The knob for the internal timer on the 371 control, or the dial component it's connected to, appears to have been installed upside down during the rebuild. The template around the knob has 30 minute marks starting at zero (in about the 8 O'clock position)clockwise to 24 (at about the 4 O'clock position). Between 24 and zero on the bottom side of the knob (or between about the 4 O'clock position and the 8 O'clock position on the bottom side) there is nothing and the knob shouldn't be able to point to that position, I believe. It does though The knob will actually rotate from the 2 O'clock position, clockwise to the 10 O'clock position and stop at both of those points, rotating all the way through the bottom end of the dial where there are no markings. It is not able to rotate between the 6 hour mark (at 10 O'clock) and the 18 hour mark (at 2 O'clock). Is that clear?? It seems to be upside down. Is this possible?