warm weather shut down
Controlling a Viessmann Vito 100W for a friend. The building is a four apartment building four zone. She would like to stop heating these apartments when the temperature is above a certain point. The home owner will often find the heat on and the windows open. I can't for the life of me find a wwsd or equivalent anywhere in the set up for this boiler. Am I missing something? I've been through the parameters and still nothing. I did not install this boiler but I did recommend it. It is a huge improvement over the four antiques previously doing the job.
Comments
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I like Viessmann. I have installed many commercially and residencially and have never come across this question before. It may not apply to Viessmann as they are made differently than a "conventional" heat plant.
I'm wondering if you are asking for a shutdown and a layup of the unit.
On that unit, I think you only need to turn the switch off until the heating season arrives again.
A quick call to Viessmann tech support should get you the answer. 1-844-649-5886 or 1-888-484-8643
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I suppose you could install you own wwsd control and wire it to shut down the boiler. Perhaps someone who knows more about Viessmann will comment.
I would think wwsd terminals and sensor would be included with the boiler.
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@Intplm. A switch off will means that the boiler will not operate when selected by the boiler operator. Not an automatic operation. . WWSD Is a feature of outdoor reset that will stop the burner at a given outdoor temperature. If we were to select 65° For example, whenever the outdoor temperature was above 65° the burner could not operate to generate space heat in an apartment. Whenever the temperature dropped below 65°F, like say every evening, the burner would be able to operate. This would be an automatic function, not a manual function.
Warm weather shut down or WWSD is a common feature on outdoor reset control devices. I have no idea why Viessman would not include it on their equipmentEdward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Is there an outdoor sensor installed?
On their 200-W, the room temperature adjustment is WWSD.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
I'd be surprised if there were no WWSD and I feel I'm just missing it or Viessmann is using a different terminology. Of course we don't want to shut the boiler off as it's making DHW with an 80 gallon tank. I can set the time for DHW production so it seems odd that there is no obvious input for WWSD.
It's not uncommon for form our night to drop into the high 30s low 40s into the beginning of June so when that happens heat comes on and often the windows are wide open. Window and door etiquette is had to instill sometimes. There is always the option of disconnecting the TT's with a switch but there has to be/ should be a better way.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
Perhaps a analogue outdoor temperature sensor like this, in series with the thermostat.
https://www.supplyhouse.com/Johnson-Controls-A19AAB-4C-Fluid-Cutout-Temperature-Control-30-110F This would act as a WWSD for each apartment.
This one is less expensive. https://www.supplyhouse.com/Johnson-Controls-A19ABC-24C-Single-Stage-Temperature-Control-w-8-Capillary-SPDTYou can also look into adding an alarm system that has sensors on each window. I have scene where the sensors are connected to the security alarm in the event of an unauthorized entry. That output can be also be sent to a time delay circuit that will open a set of contacts if the windows are left open for more that 20 minutes. This then disables the heat to any apartment that has open windows regardless of outdoor temperature.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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That's an option though somewhat cumbersome I think. I have not yet contacted Viessmann thought I'd check with you guys first. I suppose I could also interrupt the end switch on the zone control as the boiler's PCB is in control of the DHW.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
I would not interrupt it at the zone valve end switch. The thermostat will still call for heat and open the valve. Even if it did not operate the burner, whenever any other zone called or there was a call for DHW, there is the chance of flow to the apartment. By interrupting the thermostat to the zone valve with the outdoor thermostat, you will have a closed zone valve when ever the temperature is above the WWSD temperature you select. There is a 3°F differential on the control so you may need to select 66° or 67° so you always provide heat below 65°F outdoor temperature.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Which 100W do you have? B1HA or B1HE? Or is it a combi?
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
It's a B1HE-150
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
That's a good point I hadn't thought of. I do not want the valves to open though the LLH might keep the heat from migrating into the heating manifold?
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
Sorry for my delay. Yes there is an out door sensor so the boiler does know the temperature.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
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I agree. But I like trying here because of the huge brain collective.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
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If you have an outdoor sensor attached, WWSD is enabled and you can adjust it with the parallel shift setting.
Curious that Viessmann doesn't let you adjust these parameters separately as they micro-manage every other setting that you can and can't imagine. Also, the two - WWSD and parallel shift - have little to do with each other.
As BowTieEd said, there is a 3° temperature differential on the sensor, so adjust it below where you want it to turn off.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab1 -
Some models now call "shift" "level" I don't recommend messing with this setting too much, I often see contractors crank this value up in an attempt to flatten the curve, but this will cause the boiler to fire during warm days. Many contractors will also crank up the curve "slope" in an attempt at fewer callbacks as a result of cold rooms. If you think the boiler is overtemping the space, adjusting the slope down slightly may help. Note that if your level, or shift, is above zero, that adjusting this value down will also reduce the supply temperature, so if you have a level value above zero and you adjust it back to zero (68f outdoor temp) you may want to hold off on making any adjustment to the curve.
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Ok this all makes my Logomatic seem like a T87 LOL. I'd rather not make any shifts that will effect supply temp as the spaces are hated with parameter convectors and I have no idea if anyone did any calculations when they were installed. Likely not.
So Alan and G are you saying that to your knowledge this shift is the WWSD?
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
Check and see where the shift is currently set to and adjust as necessary. A few degrees may not be noticed.
Yes, I checked with V. tech. support this morning. At first, he said that both the shift and slope will affect WWSD, but I questioned the slope and he corrected himself to just the shift.
What is a "parameter convector"?
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
Oh sorry.. perimeter. base board, SlantFin or something. I'll go back this week and have a look at where the curve is now. I'll also have to read up on what all that means. The building is about 200 years old and poorly insulated on most outside walls but the windows are newish. Most spaces are reasonably comfortable at or near design days it's just these shoulder seasons where it is cool at night and sometimes hot during the day. In Massachusetts I think you're allowed to turn the heat off on 5/31 but I think having a temperature setting make the decision as to when to fire the burner makes more sense.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
You can set the shift, or level to a point that you want the unit to shut off, and then adjust the slope to get the supply temp you are looking for, for example lets say I lower my shift below the zero value but I still want my boiler to fire hot when not on WWSD, I would just adjust the slope UP to compensate, the boiler will not fire above its adjustable setting for space heating of 180. If you are using a setpoint temperature only, (no outdoor sensor) then the unit won't know what the outdoor temp is anyway so your best bet would be a 3rd party sensor that would break the TT at a given outdoor temperature.
I'm not sure your exact situation but perhaps a conversation with the tenants would get you farther along, maybe a couple of them are using the oven and open the window in mild weather as it overtemps the space, might not even be the boilers fault. If the windows are open in the coldest months then you can almost certainly dial the slope down a bit.
to check your setting from the home screen.
hit the 3 lines button (menu)
select "settings"
select "heating curve"
record the values shown on this screen for slope and shift (or level if it says that)
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Thank you for that it's helpful. I'm just helping out a friend here. She has now idea how this works and the installers is not helpful either. It's a pretty good install and a very good boiler it just seems maybe the commissioning was done correctly.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
I have to admit that I find this level of complexity and automation almost incomprehensible. More to the point, completely unnecessary to accomplish the desired functions of the equipment. Oh well…
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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It's really just selecting a couple of values from a table of recommended settings, the entire setup is explained quite simply in a single page included separate from the manual for ease of use, and every setting is displayed in plain english. it is no more difficult than setting an aquastat
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I don't have the manual with me but I'll sit down with it this week in the persons cellar and play around. With the feed back I've gotten so far I should be able to get my head around it. I'll keep you all posted.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
To further confuse the issue, I only suggested the analogue outdoor thermostat as a last resort id there is no WWSD function in the boiler software. I thing the boiler can be set to produce the function you want. Sometimes translating other language I/O manuals to English you will find the most simple concept is often overlooked, hidden or misinterpreted. Just because the manual does not have the letters WWSD in there, does not mean it ain't there
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Quick start guide
manual
don't sweat it too much, first thing to check is that the outdoor sensor is hooked up, if no sensor then you have no WWSD. After that check the settings I guided you to in a previous comment, the level will alter the WWSD, zero is targeting an indoor temp of 68f based on the slope, you do not want the level to be above zero. If you lower the level (WWSD temperature would be lower), consider raising the slope to compensate. If your friend wants to dial in for efficiency they can lower the slope to reduce the supply temperatures during the heating season. first and foremost they want the boiler to shut itself down during warm weather though, so make sure they have the sensor hooked up, determine how the thing is controlled, and then check the slop and level/shift
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@Grallert Something is not making sense here. You say:
"The building is a four apartment building four zone. She would like to stop heating these apartments when the temperature is above a certain point. The home owner will often find the heat on and the windows open."
To me, that says each unit has its own thermostat and that each unit is overheating so much that they have their windows open. Stupid question: Why not lower the individual thermostats?
Furthermore, if there is overheating, the boiler settings are wrong. (I resisted putting the last phrase in all caps.) Slope is wrong - check it! Shift maybe is wrong - check it!
And get that installer back. We all make assumptions when setting system responsiveness and we learn when we do things wrong. Make - allow - him get the feedback he needs.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab
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I'm not sure why the windows would be open but I can imagine a scenario where this would happen. I'm not certain there is over heating. My impression is that sometimes the windows are opened and then remain open for some reason. Maybe the tenant heads off to work, forgets doesn't care etc. "And get that installer back." "We all make assumptions when setting system responsiveness and we learn when we do things wrong. Make - allow - him get the feedback he needs." I can't tell you how many times I've been called to someones house to straighten out an issue from a previous installer. There are 900 people in my town, I get a few calls, can"t get away from it.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker2 -
I’d still like to know what controls the zone valves.Thermostats? If so, are they in a locked enclosure?
I’d also like to know what the heating curve and shift values are and what they get changed to.
Can you get back to us with that information? We’re here to help and there’s gratification in completing the step-by-step process to finding a solution.8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab2 -
The zone valves are controled by therostats not sure what kind I havent been in the appartments since they were installed by the HO. I think they're programable with a locking feature maxed out at 68? not sure.
These are run to a zone control. A make I'm not familiar with. I haven't been back so I'm not sure the shift or the curve. I will certainly get back with all of the details.
It's a big week for use here at school so I'm spread pretty thin for the next few days. I will be back with details.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker1 -
OK so I did get back there this weekend for a quick visit. I did not get into the curves but I did find out there no over/under heating problems per say. The HO says that while in the cellar on a 70 day she noticed the supply piping on some the zones was hot. So as she pays for heat in these apartments she was concerned. I get that.
What did occur to me while there is I can disconnect the zone control. I don't think there will be any harm in this. The valves are Caleffi Z151000 and the zone control is a Caleffi ZVR106. There are 5 heating zones and a pump on the system side of a LLH. The boiler maintains the DHW.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
Does the boiler have tankless coils that require maintaining a 160° or better water temperature?
OR
Does the DHW come from an indirect tank (or tanks)?
There is a savings to be had by having a cold start boiler with an indirect, in leu of a tankless coil boiler setup.
As far as the zone valves opening are concerned, I think that since there is heat in the boiler for DHW on a regular basis, I would opt for the outdoor temperature bulb thermostats in series with the room thermostats is a great idea. Keep the zone valves closed when ever the OD temp is above 65°
Another consideration is Ghost Flow. even if no thermostats are calling for heat, if there is hot water in a pipe, the nature of thermocycling or gravity flow can actually make hot water rise in the same pipe as cold water from the radiators in the room fall to the basement. This ghost flow can make the pipes in the basement hot and be annoying to the tenant. It is explained in this booklet https://s3.amazonaws.com/s3.supplyhouse.com/product_files/108119-Reference%20Guide.pdfon page 11 right column. and on to page 12
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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The boiler is a modcon, does not maintain a temp. The indirect is it's low limit. The indirect is a viessmann 80gal.
So it is essentially a cold start boiler. The boiler is hydraulically separated from the system. The end switch on the zone control calls the boiler when there is a heating demand and a sensor calls the boiler when there is a domestic water demand. The domestic priority if off. So disconnecting the zone control will not have any affect on the domestic side of things.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
I don't know where all that came from. BowTieEd was posing a possible answer for why the owner felt hot pipes when thermostats were off, i.e. phantom flow.
He also suggested wiring the thermostats in series with a switched outdoor thermostat which would prevent zone valves and pumps from turning on when the outdoor temperature was above setpoint. Yes, good idea, but you would need one for every thermostat; cumbersome.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
I'm sorry if that came out wrong sounding. I don't mean to be short. I can't see why the supply pipes would be warm or hot unless the boiler pump was calling for heat. With valves closed and a LLH in the way not to mention the system pump seems unlikely. That's all I mean. I do like the idea of switching thermostats with an out door thermostat. Wouldn't it be easier to switch the whole zone control as it's only controlling the heating zones?
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0 -
Can you take a few pictures of the install?
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Yes I'm sorry I neglected to to that. I did take pictures of the controls and numbers. If I can get backthis week or weekend I'll stand back and get an over all view. It's a pretty decent install in a poor location. The system piping could be neater I think. I'll get some pictures,
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker1 -
Ok well I got the pictures asked for. I asked the HO to take them. The zone control is on the back of the boiler mounting wall. It's powered through the service switch. The only connection to the boiler is the end switch.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker0
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