Buderus Logamatic

Zman500

I am getting ready to have a new G115/WS 3 Buderus boiler installed and am considering the Buderus Logamatic control. Any experience with this device, good or bad?

Big Ed_4

No Problems

It's a very reliable control with very few problems......I had one bad one out of the box , another which I could not switch to American and thats it...... But with all of them that I service over the years .I have to say it's a very reliable control ... You can program the control to drop the whole house temperature and kill the hot water production when not at home or at sleep or keep up the hot water production at all times ... You can make your own or follow some of the entered programs ..Or no program at all ... There is a freeze protection for the heating system if the burner shuts off ... You can have the installer install the jumper to turn on the run clock ... It's a way to figure your oil consumption .. Nice if you have a buried tank and you buy COD oil .. A vacation clock which you can set the control to stay on set back and return the house to heat and water production just before your family arrives home ... A room sensor can be added if you what an easy access to the control ..It also helps fine tune the control . You can adjust the heat out put and over ride the set back program if you like ... But other then that the sensor is not needed for normal even zones...



I would Like to see a few added features like a heat boost and a separate hot water adjustment when set on manual .... I just added this hoping the Big German Cheeses may bend to the call of us trench grunts ..

o311sta

Buderus Logamatic

I think it is slick and tops off a buderus nicely, how ever its a bit pricey.  If your looking for outdoor reset and night set back talk to your installer about other options (ie tekmar) for reset and set back thermostat. You could save a few bucks

Paul Fredricks_3

.

We had a customer install one because he wanted the best. But he also wanted to heat to come on instantly when he turned up the thermostat. And he wanted hot water 24-7. He wasn't happy until the thing was set to manual at 190°.



As long as you are willing to set your thermostats at one temp and not touch them, this control will work well.

k_2

RE

I have one and so far it is great



I think your customer might have been happy if he had a room sensor, I am thinking of adding one, close the loop and all



I am just getting into playing with the temp curve, I wonder if raising the floor rather than the ceiling might be better.



Mine came preset with some stupid setback things, I mean only the Germans will have a call for heat for oh, six hours without, hey maybe firing the boiler. The moral is, read the manual, the thing is doing a bunch of stuff that may or may not irritate you.



With a 'dumb' thermostat it does not do anything with waste heat, no biggie in my case GB125BE it eventually warms the boiler room, but you would spin the circulators for a few extra minutes, or allow the hot water to go up a few degrees over setting, but I have found nothing as of yet.



Oh, and is it worth it?



Had one lockout, oil line gelled. Accidentally left it in manual for 3 days before realizing. Per the hour meter[I was tracking it at the time] it ran conservatively 10 percent longer those days than any other of similar weather. Boiler runs average 5.1 hours[or somesuch] a day over the last 70 days. A few days 4 obviously a few more days at 6. The only 7 hour day ever came in this time period, it was like 7,6,6.



And yes,I bought the middle size one, did not have the guts to buy the little one, and it is running a 25 percent duty cycle on the coldest days. No guts no glory.....

Paul Pollets

Costs

The Logomatic 2107  is cost competitive with the tekmar control that can do the same functions. The Buderus control is configured to work with the Buderus boiler. It will allow a DHW indirect tank app, high temp pump and low temp circuit with the addition of the mixing valve card. Very reliable and will certainly reduce operating costs of the boiler by 10-30%. Very worthwhile investment.

Robert O'Brien

No guts?

"And yes,I bought the

middle size one, did not have the guts to buy the little one, and it is

running a 25 percent duty cycle on the coldest days. No guts no

glory....."



Little one? In comparison to what? If you do the math,why would you not believe it?

Zman500

I'm Convinced

OK, I have heard good things about the control and will get it.  My contractor said that he does not use the night set back.  He says it comes pre-programmed with that and he removes it (I guess turns it off?) because he's had customers complain of too cold at night.  I would think that if one coordinated the thermostats with the control set back it would work well.  For example, lower the stat at 10 pm and have the logamatic set back start at 10:30, and then the logamatic kicks it up at 6:30 am and the stat is raised at 7, so the boiler will be hot by the time the stat wants more heat.  Does that make sense?  I guess some customers don't know or want to bother with such a routine, though it could be automatic with a programmable stat. 

Big Ed_4

Hot Water 24-7

You can set the control to maintain hot water 24-7 .. To set it look in the owners booklet . It is not in the service book and it comes pre set to drop production on off set...



I found a few customers that had a hard time accepting the lower radiation temperatures . One tenant in one home complained " All I can get is 70* in here " ...

Big Ed_4

Not really

That would not make a difference .. With your reset , the thermostat is now used as a limit .. The max room temperature you would like is set on the control or on the room sensor . To have your comfort temperature on a given time, program the control to start up sooner . How soon depends on your set back and outside temp ... I recommend a setback of 5-8 degrees and program an hour before you want your comfort temp... Keep your main thermostat set to your comfort temp all the time .(Also program second zone thermostats to turn up sooner if you what the change in the Day / Sun period unless that thermostat has heat recovery ).. Remember the hot water production starts first , then heat is sent up... ... Let the control nickel and dime for max savings .... A boost is nice to satisfy some of our American customers but I am sure is a little less efficient , but I would like to have the choice out there ... The best part of a reset is the comfort . No hot cold cycling and a very even heat ...

k_2

RE:Robert

wow, hating this interface today, try to back up and it duplicates posts, that it had eaten anyway



sigh









>>>>>Little one? In comparison to what? If you do the math,why would you not believe it?



Boiler was almost the first item in a large renovation. No way to check infiltration, no previous year heating to compare, 40 year old house with 750 sq ft of glass, so a lot of 'ifs' that happened to [apparently] go our way. Also  were able to do almost everything on our efficiency checklist[still not done]



So between the 76kbtu and the 96kbtu I went 96

I can make excuses and say it is sized for the hot water load.... or that I was fuzzy on an uninsulated concrete foundation......and the infiltration.....but I didn't trust the math

k_2

RE:Robert

k_2

RE:Robert

Big Ed_4

Normal

Thats normal , nobody fully trusts the math and do we really know what's in the walls with a measuring tape,... And yes the hot water is a large load , everyone hates to wait for hot water .. ,With only a 20K difference , your not grossly out of the ball park ...

Zman500

Hope calcs are right

I am getting the small 76k btu boiler. It's smaller than my present one, but the contractor did a heat load calc and came up with 66k requirement, and I did my own and came up with 64k, so the smaller one it is! Hopefully it will be ok.

Zman500

Re

Maybe I don't fully understand but if the thermostat is set the same day and night, then when the setback kicks in, won't the boiler have to run harder or longer because the water circulating is not as hot?

Zman500

Logamatic Question

I just had the system installed with the Logamatic. If I want to raise the temp in the house by 10 degrees or more and it is not too cold outside (like 50 deg), it takes forever. I could switch it to manual and set the boiler temp to 180 until the house heats up, then switch it back to auto. Is this the best way to speed up the warming?

Paul Fredricks_3

In my mind....

Don't set the temp down 10°. Or plan for the slow recovery. By going to manual you are defeating the purpose of the Logomatic.



Just my .02

bill nye_3

logomatic

Zman, The control works very well and it can save you money if you let it. You have to understand how it works and what it is trying to do.

First, it is not one size fits all. It takes a little adjustment and a little tweaking to match the control to your system. No two houses have the exact same heat loss, same amount of radiation , same outdoor temperature, etc.

Your contractor, (any contractor who installs one) should have enough understanding to customize the settings to your particular application. If not, and you are tech savvy and read the manual........... well never mind. You should be able to find some one who is willing to set it up for you.

 The room thermostat is the worst enemy of your logomatic control. It should only be used as a High Limit for the zone. The ideal condition would have near constant circulation of the heating zone. Adding heat at the rate that it is being lost to the outside. This will maintain the room temperature and not really be able to increase it. Especially at your example of 50° outside and not being able to recover quickly.

Night setback is accomplished by setting the boiler water temperature back, the pump continues to run but with cooler water. The setback temp. is fully adjustable and works quite well. Domestic Hot Water production can either be on or off during setback. Think of a non-residential building like an office , no one cares if the hot water heater does not run if no one is there. How much heat is an indirect going to lose over night? You set the recovery for an hour before you get up or before the office opens.

Basically , the colder it is outside the warmer the boiler temperature. I have no thermostat or indoor sensor hooked to my Viessmann Trimatic (very similar to logomatic) and the temperature inside house rarely varies more than 1°F. I rely on the outdoor sensor. It took some fine tuning and a little fall/winter seasonal adjustment.

For every three degrees F you can turn back your high limit you should save 1% of your annual energy cost. At 0° F outside my boiler temp. rarely goes above 160°. I hope I made this as clear as mud. I have installed many 2107 logomatic with good results. I don't do it every day so a good tech who can and is willing to read the directions should be able to hook you up.

The result will be a even ambient temperature in your home with no dips and spikes in the temperature. Very little expansion and contraction noise from the radiation or heat emmiters. And piece of mind knowing that this control only wants to save you money. That is what it does. The price of fuel looks like it is only going to go higher.

Zman500

Thanks

Bill, thanks for your thorough explanation. I am fairly tech savvy and interested in how things work, so am willing to work with this new device to get the most benefit. I understand that near constant circulation is ideal. I would think that would be hard on the pumps, however, to be on almost all the time...but maybe they are very durable. Anyway, I was used to turning down the thermostat about 8 degrees at night, but will discontinue that practice. It is curious that I would save money by having the house warmer at night. If I keep the thermostat constant, than when the boiler goes on night setback, I would think that the circulator would work longer. Seems that some temp decrease should be done at the thermostat at night to have it make sense to lower the boiler temp at night. I would think that if I lowered the thermostat by maybe 4 degrees just prior to the night setback time, and restoring the thermostat back up 4 degrees just after the day mode kicks in, I would be taking advantage of the night setback, so the boiler at night won't heat up as much, but the requirement will also be lower. Does that make sense?

Zman500

Thanks

Bill, thanks for your thorough explanation. I am fairly tech savvy and interested in how things work, so am willing to work with this new device to get the most benefit. I understand that near constant circulation is ideal. I would think that would be hard on the pumps, however, to be on almost all the time...but maybe they are very durable. Anyway, I was used to turning down the thermostat about 8 degrees at night, but will discontinue that practice. It is curious that I would save money by having the house warmer at night. If I keep the thermostat constant, than when the boiler goes on night setback, I would think that the circulator would work longer. Seems that some temp decrease should be done at the thermostat at night to have it make sense to lower the boiler temp at night. I would think that if I lowered the thermostat by maybe 4 degrees just prior to the night setback time, and restoring the thermostat back up 4 degrees just after the day mode kicks in, I would be taking advantage of the night setback, so the boiler at night won't heat up as much, but the requirement will also be lower. Does that make sense?

ScottMP

ZMAN

Either use the room thermostat or the Logomatic Not Both.

BIll is correct, set the room thermostat for the temperatreu you need and leave it. Then use the logomatic to set your set back temperatrues. The logomatic uses a heating curve and adjust the temp of the heating water according to the outdoor temps. When using the night time set back, the Logomatic shifts that curve down. If the room needs 150° water to heat the room the control may send 140° so that it heats the room but never reachs the temp. the thermostat is asking for. Does that make sense ? In that way it is setting the room to a  lower temp, and using constant circulation. If it takes to long to warm the house up in the morning you can take it out of ngiht time set back earlyer. Or you setback is too deep. I agree with 7/8 degree set back but thats up to you.

So if want to wake up at 6:00 and you come out of setback at 5:00 and the house has not reached 68° then come out of setback at 4:30.

You can not have the thermostat and the Logomatic each doing set back, they will fight

D107

Logamatic

HO here with G115/21 and Logamatic in the family house. This highlights the need for a morning boost on the Logamatic, its major drawback IMHO. Night setbacks--which many people prefer for comfort reasons--would be no problem if the boiler water temp would automatically go to 180+ just for morning startup. That boost might not save money, but would give that night temp comfort option. We leave the clock on daylight savings time all year, which means that the morning startup is at 4:30 (first to bring DHW, then house temp) and night setback begins at 9pm instead of 10, so some economy is achieved. (Obviously even with a 10 degree setback, house temp may not go down more than 4-5 degrees many nights overall.)



T-stat night temp is set for 60 (Logamatic set for 63; T-stat day temp set for 70 (Logamatic 72). Buderus has recommended Logomatic setting be set a few degrees higher than the t-stat. Ref Temp 167. Building Response set to 1. There's quite a few tricks and specs you can learn from Buderus techs, that unfortunately are not in the manual.



FWIW, over the years, I've gathered info like this: (This could have interpolation or transcription errors but is basically what I was told and sometimes different techs give varying advice.)

 

"The Offset mostly affects the starting temperature of the curve. If the outdoor

temperature is mild and more water temperature is needed, then the “Offset” is

raised. The “BLDG RESP” is how quickly the control will respond to the outdoor

temperature. We recommend this setting be changed from #2 to #1 since most

people are not used to the slow response of outdoor reset. The “Day” and “Night”

settings are values used to help determine the heating curve. The Day and Night

Settings have more effect on the curve if it is colder outside and less on mild

outdoor temperatures. The “Ref Temp” raises the entire curve through out mild

or cold outdoor temperatures."

GW

yes

Depending on how you slice and dice this topic, you are correct. Trying to explain the nuances of a 2107 to a home owner is a very difficult task. Some systems your silly not to use a bfu room sensor. Other "American-ized" multi zone fin tube baseboard systems are better off keeping it more simple.



So you're right. If you drop the 2107 and the conventional stats at the same time, you have a decent shot at "guessing" the heat loss of the house with the reduced output of the lowered temps/heating output in MOON mode.



Gary

k_2

re

I am thinking of installing a room sensor, since that would give the control a closed loop. thermostat setbacks i think argue with the control

Zman500

Makes sense

What you say makes sense, about leaving the thermostat at a constant temp and the lower boiler temp at night takes care of the lower desired room temp at night. The constant running of the circulators in this scenario and the thermostats never getting "satisfied" all night are what bothers me. Its a real change in thinking and something I have a hard time embracing, but I'm getting there. Thanks.