The house is about 2900 sqft. The 6 yr old Burnham boiler is 134MBH output (DOE). It is about 30% oversized for the 105MBH heat loss calc but 5% undersized for the connected indirect water heater. No questions there. The house was built in 1930 and was apparently originally gravity fed. There are 2” mains leading to smaller feeders to a total of 23 cast iron radiators. The total calculated EDR is 1050. The boiler is located in the basement of the two story above grade house. The first floor ceiling is at 9ft – probably safe to assume 15ft vertical worst case from the basement for 2nd floor piping, 4 feet vertical to the 1st floor and as stated 2” and 1-1/2” steel mains in the basement. The length of 2” basement main is about 30 feet. All these dimensions are for supply – same sized returns are however adjacent. Near boiler piping is 1-1/4” copper. The boiler has bypass with a Taco 007’s for the indirect, boiler and a kitchen radiant zone. There is outdoor reset with a Tekmar 260 controller and a relay box connecting the kitchen radiant and main house thermostats to their pumps. The Tekmar is set to 180 max and 140 minimum.

Finally my issue!! I discovered the main house zone is circulated with a Taco 0011. I now realize this explains the velocity noise. Also the boiler never gets to the target temperature since the flow and pump pressure is so high and fast. The Tekmar frequently show targets at 160+ and higher but hangs for a LONG time at about 120+ when the main zone kicks in. You can hear the pump kick in when on the 2nd floor. It takes forever for an in house temperature rise then cold radiators – no real steady comfort.
Question: Which pump is correct - should I change to a Taco 007 or a 0010 pump? Given the likely low head, the choice seems to come down to high flow vs medium flow.

I have read posts that argue for both. Some homeowners have complained of inadequate heating when they went with the 007 – I assume because of the system water volume. At lower head pressure the 0010 flow seems similar to the 0011, probably too high.

Thanks in advance for the help and advice!!!!!

 

Why not get a variable speed circulator?

 

Lynn, please describe what type of bypass is installed, and how it is adjusted.

You're certain that it's 'velocity noise' and not air circulating in the system?

There are other possible reasons for this. In point, the question about your bypass, above.

And you know, I'm sure, that this is very bad for the boiler, flue pipe, and chimney.

Can you take and post some pictures of your system please? We may see something that isn't piped properly.

Have you lived in the home before and after the new boiler was installed?

 

Aside from my other questions, I do believe that this is the wrong pump, but we'll get to that after a while.

 

So having a system on continuously is bad? I thought short cycling was bad for the boiler having to shut on and off continuously?

Thanks.

 

Hi Gene, no it's not a problem for the system to run a long time...

It's a problem for the system to run a long time AT LOW TEMPERATURE.

You end up with the flue gases condensing inside the boiler, flue pipe, and chimney.

Flue gas condensate, whether from oil fire OR gas, is ACIDIC and will slowly EAT anything it comes into contact with.

The above is assuming a CONVENTIONAL boiler, NOT the ones that are designed to condense...

 

I have successfully set up constant circulation and added an indoor thermostat to my Tekmar 260. The issue now is that the system overshoots temperature.

I have attached a diagram of my current system setup.

I would LOVE to get some expert comments. Do I need the system pump P1? Each zone has its own pump. Pump P1 runs whenever there is a demand. Is the boiler temperature sensor correctly located? Is my bypass piping enough to protect the boiler or is a system mixing valve still recommended? Any ideas on boiler/indoor temperature maintenance?

 

Hi Lynnwill, You never came back and answered the questions I asked in your previous thread.

http://www.doityourself.com/forum/bo...dium-flow.html

In fact... I think I'll merge your old thread with this one.

 

system.pdfSorry for not returning but I did make some system changes. I changed the main zone system Taco 0011 to a 007. The velocity noise disappeared! I added an indoor thermostat sensor to the Tekmar 260. My intent is to establish constant circulation by setting the normal thermostat higher than the Tekmar setting. In theory this would establish full time demand but the Tekmar would regulate water temperature to maintain its lower design indoor temperature. This works but with the boiler minimum set to 140 the temperature overshoots. I don't think I can set it much lower. As described earlier I have a very high mass converted gravity system and a cast iron boiler.

As you can see in the diagram ina previous post I appear to have a simple bypass with no mixing valve.

I bought the house with a 330MBH, 1960's vintage boiler (insane). It was changed. The actual heat loss has been reduced even from that in 2006 due to new windows, insulation, etc.. Based only on manufacture ratings for the DWH the boiler is still OK.

 

I'm unable to relate what I see in the diagram (PDF file) to what I see in the pictures.

Stand back with that camera and take some wide angle shots too.

 

Doesn't sound that successful to me if it's overshooting the temp.

I doubt if you will be able to run constant circ with that boiler. You can't run the boiler temperature low enough for that. You would need a whole lot of piping changes to achieve that.

 

No problem. I will try to translate.

The first photo is pump P1. It is attached directly from the boiler supply output and runs with all boiler demands

In the piping drawing: At left is the radiant zone mixing valve and its pump. The mixing valve is black with red letter lettering. At left of this is the fresh water supply with an expansion tank. The radiant mixing valve has inputs from supply and return. 2nd from left is the main house pumped zone. Barely visible at the bottom right of the photo is the DHW pump. At the bottom right is a TEE connection between the supply and return -no valve.

I hope this helps

 

Would the piping changes likely be as expensive as a replacement with a true a condensing boiler?

 

Yeah I get all that, but I don't think what you've drawn is accurate to what is there...

Please take more pictures and try to show all the piping so I can get a handle on what you've got.

Shouldn't be I wouldn't think, but finding a competent professional to design and make the changes you need will be a challenge.

 

BTW - The pipe on the far right of the piping photo should be ignored. It is just a 3/4" fresh water supply for the water heater. It looks large since it is closer to the camera.

 

Because what I see is significantly different than what you have drawn, and I believe that what you believe is a 'bypass' is not a bypass at all, but rather a pair of closely spaced tees for a primary/secondary setup.

I need to see how those pipes are connected above, and below.

Your textual descriptions won't work because of your misconception...

 

I make no claims at professional photography of high level knowledge! I agree with your statement that finding a local professional will be tough. Few seem to actually have the detailed understanding you exhibit. I am attaching two new photos.

Any recommendations are welcome. There is a TEE between supply and return as you seem to describe - no control.

I appreciate the time you are taking with this!!!!

 

I need to see up TOP TOO! Where those pipes go... how they connect to the rest of the piping that leads to the radiators.

Your pics are fine!

What's that dark stain looks like water under/around the boiler?

Do you think the installers could have put your expansion tank in a more inaccessible spot? jeeze...

 

Here are two attempts to capture the top area. If you can make sense of this you should receive some kind of award!!!!

The stains are really nothing. Earlier pressure valve blow off due to a mistake I made with overfill, water pressure valve etc - nothing really and it is resolved.

You are so right about the expansion tank. It is an example of the issues described your statement regarding work by a true professional who understands design. Since the 2006 install they had to actually replace the tank - unnecessary hard work. At least they did place valves on either side of the circulators. It made replacing them easy.

 

I see what I need to see, thanks, that's great...

Here's what I DON'T see: None of the pictures show any kind of air scoop or vent. This will lead to having to constantly be bleeding the radiators.

What you have there is not what you've drawn, I can be sure of that now that I've seen the whole setup.

Your radiators are on a PRIMARY loop, and the boiler is the SECONDARY loop.

Your indirect heater and the radiant zone are piped off this secondary loop.

There are some piping issues, we can discuss down the road. The indirect pump for example should have been before the P1 pump. There's no reason to have to run both pumps on an indirect call.

Not sure about the radiant subsystem... probably not technically correct either...



Yes, you do.


I don't think so, if I'm interpreting your drawing correctly.


I'm going to scribble on your drawing a bit to reflect what you actually have...

 

This graphic much more closely represents the way your system is piped:



Now that we've got that out of the way...

What was the problem again?

 

The graphic shows where your 260 sensor SHOULD be. Right at the boiler outlet. You want it to measure the boiler temp, not the temp down the road, which will be cooler by the time it gets there... not much, but a little.

Your water heater takeoff and pump are in the wrong place. That should have been BEFORE the P1 pump, and the controls should have been wired such that the P1 pump does not run when the water heater calls. The water heater should have been piped in 1", but 3/4" will obviously work. You might take a little recovery time performance hit... but might not even notice.

What you MIGHT have noticed is that your hot water gets TOO HOT at times. This is because even if the water heater is not calling for heat, there will be SOME flow through the water heater every time the P1 pump runs on a call for space heating.

With the pump for the water heater installed at the correct location, check valves could have been used to prevent this unwanted flow from occurring.

Looking at the drawing, understand the function of the 'closely spaced tees'. What you have is two loops connected together at that point. The flow in one loop does not affect the flow in the other loop. They are 'hydraulically separate'.

 

Thanks again for the help!!!! I guess it make sense that any discussion should start with knowing what the heck exists. As I stated, I am no expert, just a homeowner who knows that the system is not operating properly. It gets warm then cools to uncomfort, then takes another long time to reheat. It is similar to air heating just with MUCH longer comfort cycles. Also my gas bills are unnecessarily high.

To my questions:

I intended to establish an outdoor reset with constant circulation. Constant circulation seems to make sense given the very high mass and water quantity in my converted gravity system. My condensing boiler (Burnham Series 2) of course needs to see 140 degrees to prevent condensation. With a 140 degree minimum setting on my Tekmar 260 the house temperature (and constant circ) overshoots pretty badly. The Tekmar has an indoor temperature sensor installed.

I believe I may need a mixing valve. Without constant circ a large amount of cool water waits to be heated upon a demand call. The boiler temp stays for a very long time in the 120's.

Finally - I am having bad thoughts (financially) and must ask a question for your opinion. My boiler is 9 years old, cast iron, non-condensing. when I consider my high mass/water system, outdoor reset components, mixing valves, repiping, etc. - should I consider a new high efficiency condensing boiler? Will the modifications to my existing system ever get me to the efficiency offer by a new system?

FYI - my heat loss after improvements over the last 9 years has gone from about 122MBH to 94MBH. The existing boiler is 164MBH input/136MBH output.

Either way constant circulation seems like a good idea.

 

Of course you meant to type NON-condensing...

It does, but I don't think you can do it with an imposed BOIL MIN of 140F. The vast majority of the heating season you will need far less than that.

To do this with what you've got is probably going to take some sophisticated piping and control, and most likely a buffer tank.

It's complicated...

 

No question - The Burnham Series 2 is cast iron NON-condensing type.

Your second comment goes to my last question. Assuming I can find a VERY knowledgeable, skilled and interested professional, I will need to repipe, add additional controls, etc - all at a hefty labor and materials cost. Also I have no idea what has physically happened within the boiler for the last 9 years. I am starting to think that the cost should be applied to a new high efficiency condensing boiler. These can come with all the controls included - including a priority setup for my existing indirect water heater. Constant circulation would be no problem. The only convincing needed is that my wife hates the idea of visible "steam plumes" near the house exterior.

I wish I knew I had a source like this one in February 2006 when I was making my first decision on replacement.

 

the piping is all wrong.Pump 1 should be on the return pumping towards the boiler.I don't see any type of air elimination.the radiant should be pulling off the secondary loop. the indirect can come off of either. if the correct components are used and wired correctly through the 260.A tekmar 401 house control would have been a better setup. If I Installed this your expansion tank would have been a floor mounted model.
You don't size the boiler to your domestic load. That's easily done by utilizing a mixing valve on the domestic side and running the correct size boiler side piping.

 

I forgot to mention. I can confirm that no air elimination devices are installed.

 

Is there any yellow/white slag on your flue piping going to the chimney?
Have you pulled the flue piping off of the boiler breeching to see what the interior looks like?

 

I cannot help but notice NJTROOPER is in NJ and WOGPA67 is in PA. Either of you ever consult or install near Philadelphia. I at least have to ask. Is is possible to privately email me.

Thanks

I have not checked the flue but will do so.

 

Ummmm... it IS on the secondary loop.

Seems you are eager to provide a piping diagram of the way it should be?

Or are you only here to tear it apart?

 

If, I repeat, IF I were to go with a new condensing boiler. Given my conditions do you have a manufacturer or model line recommendation?

 

since when is the boiler the secondary loop?

 

don't go getting all crazy. ride the winter out and make a more informed decioson . we are almost through it.

 

You are right. I will calm down! Part of my research is where to start? Any advice regarding manufacture or model line of condensing boilers? I will look at these as well as the possibility of upgrade to my existing equipment.

Further study (by me) is required regarding constant circulation, controls, etc. I suspect I will be back with questions on this forum sometime soon.

I truly appreciate the advice and counsel. This forum is invaluable.

 

your system is salvagable if there hasent been too much condensing going on. If it's worth it would be the bigger question. two- three more months won't hurt it any more than what's been going on for years.

 

Where the boiler is does not 'name' the loop. The boiler can be on the primary OR the secondary.

THIS boiler is on the secondary loop.

Loops are 'named' according to the following rules:

The secondary loop is the one that comes off the BULL of the tees.

The RUN of the tees is the PRIMARY loop.

http://comfort-calc.net/primary-seco..._tutorial.html

 

A quick question. I am considering installation of a thermostatic mixing valve to protect the boiler and allow a full reset in my Tekmar 260 (lowered boiler minimum setting). Where in my system would a 3-way valve be located? Also any recommendation for a valve manufacturer?

With a mixing valve installed do you recommend a specific minimum boiler temperature setting in the Tekmar 260.

 

That's not a quick question, and there's a LOT more to it than meets your eye.

 

I get it. It is time for me to identify a local professional and get some on scene advice. It is apparent that I might know less than I think

I expect to come back to this forum with what I assume may be different approaches. I will then need help with analysis and determination of the best approach.

I cannot thank you enough for taking time and the responses so far!!!

To be continued...

 

I am back NJ Trooper

I have talked to a few local professionals and no two ideas (or cost) are the same. Below is a drawing which combines many ideas. Please comment. It is very different from the relatively simple P/S system which you expertly identified earlier in this post.