Joined on December 29, 2008
Last Post on July 8, 2014
@ January 7, 2014 9:49 PM in Hot water baseboard heatingThere should be TWO SUPPLY AND RETURN TEMPS NOT ONE....The boiler is piped primary secondary, in essence two separate systems. The boiler or primary side delta-t is constantly changing, ie, modulation.. They system of primary side will have a different delta-t. It is 99.9% mathematically impossible for both sides to have the exact same supply and return water temp. Here is the reason why.
The boiler/primary side has a fixed speed pump that the boiler mfg sized to move a specific flow rate each and every time it fires, You cannot no matter how hard you try change that. In this case its moving 7.3gpm in an Alpine 80.
Your system/secondary has its own flow rate dependent on what zone or zones are calling and that is always changing. The other factor is the system side pump. It again is a fixed speed pump and is always going to operate on its operating curve. In a multiple zone system one, two or maybe all zones are going to be over pumped.
In order for you to have a 20 degree delta out of that Alpine you would have to to be in high fire constantly, move the entire 7.3gpm out of the primary/boiler side into the secondary side, the secondary side would only need exactly 7.3gpm at all times and you had perfect matching boiler and system delta-t's. The odds of all this happening in harmony at all times is scientifically and mathematically impossible.
The question is when all heating zones are open and calling. The system side supply and return temps should be taken at the system side of the supply and return closely spaced tee's
1. What is the boiler supply temp
2. What is the boiler return temp
3. What is the secondary/system supply temp
4. What is the secondary/system return temp
From the pics the indirect looks to be piped on the secondary side. You then shut off the heating zones, open the indirect zones and take another set of readings. I have to say that I'm surprised but again we are only hearing your side of the story.
@ January 7, 2014 9:47 AM in Hot water baseboard heatingHas done any system side supply/return water temp measurements at all? That would be ridiculous in my opinion if they haven't. Boiler is working, making energy, making hot water. So the issue has to be on the system side not the boiler side. Without these readings how would anyone know what's going on? They wouldn't. I'm very surprised nobody that has been to this job hasn't taken delta-t/temperature readings on the heating and DHW system side. Delta-t is the difference between the supply and return temps. Since your piped primary secondary, the boiler/primary side would have a different delta-t the the system/secondary side. How would anyone know what the btu/hr delivery is without these readings.
gpm = btu/hr / (delta-t x 500)
@ January 7, 2014 9:18 AM in Hot water baseboard heatingAnd I've read every post. Nobody has done a heat loss calculation, nobody has measured system supply temp while comparing the btu/hr ouput of the board and/or DHW at those temps. Everyone keeps going to the boiler control to read temp. Has anyone done any system side supply/return readings as well as DHW supply return readings. Are you over pumping? What are the delta-t's. Nobody has started with the basics, everyone keeps running to the boiler. What's the delta-t on the boiler/primary side? This sounds like a hydronic problem not a boiler problem..
@ January 4, 2014 9:17 AM in Vitodens 100-W temp setting questionThe outdoor sensor and set a curve.
@ January 4, 2014 7:46 AM in Vitodens 100-W temp setting questionMeans no reset, means no turning down. Boiler is just riding the curve at that dial setting.
@ December 28, 2013 8:17 AM in Looking for resourcesAbout high efficiency systems then the boiler, The Boiler is just a heating plant that makes energy. As others have said all that information is available on the boiler mfgs web site.
I'd say, that the design side is even more important then the plant itself but to be a good designer you need to understand hydronics. I'd suggest you start with these great tools from our friends at Caleffi. These great resources should be on every professionals bookshelf.
Another suggestion is for you to join the Taco Flo Pro Team and John Barba's Neighborhood at www.taco-hvac.com
@ December 19, 2013 7:21 AM in Boiler blues in NYCHe was not under contract to perform any services. The service you received and advice at this point was free. You also had the ability to call as many contractors as you wished if you were not happy with the delay.
Now take your ball and go home, mommy has some oatmeal on the table for ya.
@ December 18, 2013 1:21 PM in Boiler blues in NYCWith your attitude and eagerness to utilize facebook and other social media sites when you don't get your "I want it now" way, your going to find a professional to fix your installers mess? Not with a ten foot pole. Just by posting here, the contractor network will be on the lookout for your phone call.
PS...That service you did get, WAS FOR FREE!
@ December 16, 2013 2:10 PM in 6 Heaters - need one programmmable controlI'm very surprised. Where are you located?
@ December 16, 2013 1:43 PM in 6 Heaters - need one programmmable controlIf you ask them who the local rep is they will give you their number. I'm sure the local rep will give you a qualified contractor in your market.
@ December 15, 2013 8:22 AM in What is the most effective way to handle a MODCONAll the buffer is really doing is allowing the full boiler flow rate a place to go no matter the modulation rate. The pump is fixed speed. If you had a variable speed pump being controlled by the boilers control logic to match the modulation rate based on the systems demand that issue goes away and there would not be a need for the buffer tank.
@ December 15, 2013 8:00 AM in What is the most effective way to handle a MODCONHere in the great USA. Fixed speed boiler pumps. They are the main cause of short cycling most of the time, the reason for elevated stack temps and high boiler return water temps when zoning.
Get variable speed boiler pumps controlled by the boilers logic to match its flow with the modulation rate of the boiler and they go away. The attached chart is provided by one mfg as the modulation rate in comparison to efficiency in its boiler. I don't know anyone else that publishes this.
@ December 14, 2013 3:51 PM in Triangle tube not reaching setpointPosts he has participated in its a PT110.
@ December 14, 2013 3:29 PM in Triangle tube not reaching setpointIts time to speed up that boiler pump. What the heat loss of each radiant zone and the baseboard zones?
Going back to your original post. Boiler supply 140 Return 108 - 32 Degree Delta-t
(Speed 1 Flow Rate is 6.5 or so x 32 x 500 = 104,000 btu/hr. Boiler Heating Capacity is 99,000 btu/hr. The 6.5 may be a little off, estimating off a graph.. I'd say the boiler is in high fire..
@ December 14, 2013 11:14 AM in Triangle tube not reaching setpointBaseboard is on the last zone, slab is taking all the flow rate (ie, btu/hr) and the board zone is starving. Like I said 360 btu/hr per ft at that .5gpm flow rate - How many feet of board on that zone and is 360 x footage = btu/hr enough to get you to setpoint at design temp based on that zones heat loss?
Pull your triangle install manual page 82. On speed 2 the pump curve crosses the HX curve at at just about 9gpm.
@ December 14, 2013 8:44 AM in Triangle tube not reaching setpointYou stated that you were piped pri/sec. With the slabs only running you state that the boiler supply and system supply are the same temp. That would mean your slabs alone are taking just about the entire capable flow rate provided by the boiler pump. The reason I know is that your boiler return water temp is elevated by 5 degrees above your system return based on the temps you posted when just the slabs are calling.
You then posted the numbers when both the baseboard zone and slabs are calling. Your again posted that the boiler supply and system supply are the same temp. The boiler pump is a fixed speed pump. The boiler pump cannot just create more flow. If the system needs more flow you would be mixing return water temp with boiler temp at the pri/sec tees and that water temp would not be the same as the boiler supply temp and you are posting that it is.
I ran the math, that slab is taking 6gpm. The boiler pump on speed 1 only provides a 6.5gpm flow rate. So your only moving .5gpm to the baseboard? IF that is the case the bb output at 150 degree water is only about 360 btu/hr per ft.
(B Flow Rate) - (S Flow Rate)*B Temp + (S Return Flow Rate)*SysRtnTemp/B Flow Rate = Boiler Return Temp
(6.5 - 6) *105 + (6 * 73)/6.5 = 89
Are the radiant slabs the first zones and the baseboard the last?
@ December 13, 2013 5:51 PM in Friday the 13th Boiler FailureIs the better choice. Down to like 12 input.. Viessmann has a program for displays. Rather nice one.
@ December 13, 2013 5:48 PM in Triangle tube not reaching setpointOn the answer to my water temp questions. They are very important.
@ December 13, 2013 3:35 PM in Low-Loss Header: am I understanding this correctly?Just have this boiler installed? Suggest you speak with your installing contractor. To answer your question. The boiler pump speed 2 and don't know what your gpm and head requirements are for the system side so can't tell you what speed to put the system pump at.
@ December 13, 2013 3:31 PM in Friday the 13th Boiler FailureA new 200? Turn down is way lower..
@ December 13, 2013 11:34 AM in 6 Heaters - need one programmmable controlSimple out of the box stuff and can do it all from your office computer