Had boiler installed, doesn't work correctly! Please Help

[IACG]

Hi,

I just installed an indoor wood boiler in my shop which will heat the shop (30'x50' w/ 14' ceiling) and has a line to the house which will heat my DHW, has a rad in the forced air furnace and is connected to my floor heat of my garage. The garage already had floor heat which was heated with a 3000W DHW tank element. I had a guy come out to install the system for me because I didn't want to spend a lot of money installing pumps, mixing valves etc and then have something done wrong and it not work. Unfortunately, after the install, I found out it does not work.

First, here is the problem. My fire goes out on me before the wood is all burnt, the water is only luke warm coming out of the boiler. It is warm enough to heat floor heat, but does not do any good for the sidearm on the hot water tank, or the rad in the furnace. The boiler says that it gets really hot in fact it shut itself down because it hit the high temp alarm. I realize that the water at the top of the boiler is getting hot, but the water is stratifying in the boiler. I checked the flow and realized I do not have the minimum recommended flow. The instructions coming from the boiler say 14 gpm min. I have a total of 7.

With that said, I'll describe the system and include a couple of diagrams.

The shop is heated with one pump (15-59 Grundfos Pump). There are 4 loops of 1/2" pex in the floor. I measured 2.5 gpm on this loop.

The house is fed by one pump (26-99 Grundfos Pump). 1" pex pipe is used throughout this loop. The distance from the boiler to the house is 170'. Inside the house the first component in the system is a 4' sidearm on the DHWT. Next it goes to a 20"x20" rad in the furnace. After this it goes to the attached garage. Here there is a ball valve installed across the Supply and Return which I was told to leave open (otherwise it forces it through the garage system.) After this ball valve the return line goes back to the boiler. In the garage is a mixing valve and a pump, connected through my original DHWT element boiler. There are a lot of elbows (just over 20) in the system and the flow of this loop is 4.5 gpm.

The talked to the guy I bought the boiler from (who is not the installer, he does not install them, but recommended the guy who did the install.) and he suggested I put in a second pump in the return line at the house. Is this a good idea?

Here are some diagrams I drew of how the system has been put together.
Edited: I had two mistakes on my diagrams. One length was 5 3/8" instead of 36' and I drew one of the mixing valves in with it pointed the wrong way. (Sorry to add confusion)

Any help would be greatly appreciated.
Thanks!

 

[DaveBP]

Do you have anything on the return lines to the boiler to keep the minimum temperature going back into the boiler above a minimum temperature (something like 130 or 140F?

That is a LOT of heat to try to force through that much 1" PEX.

 

[tom in maine]

First look, the Garage needs its own loop. It should be in parallel with the house and the shop, not in series with the house. To force the return from the house to the garage and then back to the boiler is way too much frictional loss. There should probably be a pump on the house loop as well. The house and garage would benefit from a primary/secondary plumbing design.

 

[maple1]

You will need to measure temps in your piping, wherever it goes in and out of something.

All over. Starting with the boiler.

I can't look at pump curves from here, but that's a long run for 1" pipe - first flag.

 

[BoiledOver]

Begin at the boiler...............It does not get up to temp. After that is resolved, consider the zones if need be.

What boiler are you using? Name and capacity?

 

[IACG]

Do you have anything on the return lines to the boiler to keep the minimum temperature going back into the boiler above a minimum temperature (something like 130 or 140F?

That is a LOT of heat to try to force through that much 1" PEX.

Something to keep the return above a minimum temperature? Sorry for my ignorance, I'm kind of new at the this, hence the reason I hired someone to do it for me. A friend did tell me that the temperatures should not be drastically different, but what can I do to minimize this difference? What are you suggesting?

 

[IACG]

Begin at the boiler...............It does not get up to temp. After that is resolved, consider the zones if need be.

What boiler are you using? Name and capacity?

The boiler is a HeatMaster G200. It lists a Max BTU Output of 232000 BTU/hr and a Heat Output (8 Hour Burn) of 111500 BTU/hr. 195 gallon water capacity. From what I understand the reason it does not get up to temp is because the water is stratifying due to lack of circulation. Therefore, the top of the boiler heats up, telling the sensor to shut down the fire. It has a damper and a fan both of which shut off because thinks that my water storage is all hot. I figured if I increased the gpm, with the increased flow I might solve that.

 

[Mauler]

also check the temp sensor.

 

[IACG]

Well, I would agree except that when it says that the boiler is hot, it really is because it starts steaming out the top, yet the supply lines are still just warm. After running for a while they did get warmer, but still not what I would call hot. I could hold my hand on the elbow right at the supply coming out of the boiler. I do have a thermometer strapped to the pex just after the pump, but there is no insulation around it, so it really is not a valid measurement. It started out at around 5 degrees Celsius and the hottest it ever went to is 36 degrees Celsius.

 

[IACG]

I wish I had come to this forum before starting the project. If you can give me some advice as to what can be done now, with the boiler and line to the house as is that would be great. I laid the line to the house before pouring the shop's slab. This set of 1" lines was what was recommended by the dealer where I bought the boiler and the pipe. I told him what I was wanting to heat at the house and garage. To add another line to the house right now is not really an option. (I hope) I'm over budget on this project already.
Thanks

 

[maple1]

Sure sounds like not enough water moving, if the boiler is heating like I think you say. Could be a whole host of issues going on here, starting with near-boiler piping & continuing to each area. We would need all the temp data I mentioned above, plus lots of pictures. Not sure what an 'easy' fix for now would be, but it would likely involve adding another pump to the loop. Maybe a big one. Also suspect a poor choice of underground pipe.

Does the shop heat OK?

 

[brant2000]

That's completely unrealistic to expect to move nearly 14 GPM through 1" pex that distance. If you just find a run a quick calculation using something like this (http://www.freecalc.com/fricfram.htm), you'll see that the head loss at that distance and flows are enormous. I just did a quick calc at 350' of 1" (I would expect 1" steel without additional fittings to be similar to pex) at 14 GPM, and found the head loss to be 44'. Without looking at the curve for your pump, I doubt it even dead heads at 44', let alone can push anywhere near 14 GPM at 44'.

I second Tom's recommendation to split the garage off as a secondary, parallel loop and see if that might get you closer to minimum flow.

 

[maple1]

Just looked at the diagram again. So it's 170' (x2) underground - then another 100' within the house? So something like 450' of 1" pex? Plus all the fittings & mixer & heat exchangers? Pretty sure there's not much water going around that. You might be behind a big 8 ball starting with the undergound pipe. Curious as to exactly what kind of pipe it is - most of whatever heat gets out of the boiler could be going into the ground.

 

[IACG]

Sure sounds like not enough water moving, if the boiler is heating like I think you say. Could be a whole host of issues going on here, starting with near-boiler piping & continuing to each area. We would need all the temp data I mentioned above, plus lots of pictures. Not sure what an 'easy' fix for now would be, but it would likely involve adding another pump to the loop. Maybe a big one. Also suspect a poor choice of underground pipe.

Does the shop heat OK?

The shop and the garage were heating up nicely. My attached garage went from 6 degrees C to 15 degrees C in 2 days of running the boiler (Air temperature). This is with the boiler having gone out on me over night and then me starting a new fire in the morning. The shop also was warming up I have a temperature sensor in the floor and it went from 7 degrees C to 14 degrees C in that same time.

My side arm and rad were the issue because I need actual hot water coming to them, not just warm water as the floor wants (obviously normally done with the mixing valve though).

I let the fire die and have not had it running now since Saturday when I realized that the lack of flow was causing the boiler to not operate correctly. That's when I phoned the boiler dealer and he suggested adding another pump. I figured I should do a bit of research before just throwing another pump at it. This is why I don't have any temp data as you suggested I should take.

Thanks for your suggestions so far.

 

[IACG]

First look, the Garage needs its own loop. It should be in parallel with the house and the shop, not in series with the house. To force the return from the house to the garage and then back to the boiler is way too much frictional loss. There should probably be a pump on the house loop as well. The house and garage would benefit from a primary/secondary plumbing design.

When you suggest putting the garage on its own loop, your suggesting digging in a new line toward the house/attached garage? Or are you suggesting reconfiguring the loops once they are at the house/garage? (I hope you are because right now I can't afford to trench more stuff to the house.)

 

[IACG]

Just looked at the diagram again. So it's 170' (x2) underground - then another 100' within the house? So something like 450' of 1" pex? Plus all the fittings & mixer & heat exchangers? Pretty sure there's not much water going around that. You might be behind a big 8 ball starting with the undergound pipe. Curious as to exactly what kind of pipe it is - most of whatever heat gets out of the boiler could be going into the ground.

The pipe is called 1" pex though it has an inside diameter around 7/8". It has the two pipes with Styrofoam around it inside a drain-tile type pipe. (Not perforated though obviously)

 

[leon]

The first thought that comes to mind is thermal shock.

Is this fellow a licensed plumber?

It is entirely possible the cooled return water is not mixing in
the boiler with the hot water to then circulate the
water completely.

Where does the cold return water enter the boiler?
Where the heated water exit the boiler? They cannot
enter and exit on the same side

The cooled return water must be heated fully and then
pumped to the shop and home.

In my case the the heated water is suctioned to the
base and then pumped to the single heat loop and the
temperature balancing pump between the two boilers
I have which are a wood and coal boiler and a Buderus
oil fired boiler.

 

[Tennman]

Do you have an estimate of how much energy you want/need to dump into the house? If so I can plug that into a spreadsheet to compute gpm, velocity, and head based on your 1" pex which will tell you if the pump's adequate. Unless you have a very efficient home that's not too large, 1" is pretty small for those distances. Which means to move more btus/hr you must increase velocity, which increases head, which increases pump horsepower.

Somehow get the temp of the water entering your underground and the temp where it exits to get the temperature loss in underground. I lose about 1* or less in about the same distance (2*F round trip including thru the HX when fan's off). The source of our boiler said 1" would be adequate, but I did the math and installed 1 1/4"... for our boiler which is roughly in your class, our install would be more efficient with 1 1/2". I was in similar circumstances 6 years ago and the guys here helped me sort it out. In my case years ago it was multiple problems I needed to address. But checking pump size is a start. The diagnosis process often involves going down the list identifying what it's not.

BTW.... Did you read the underground sticky? The pipe drain I used for my first underground was not perforated, but when I sprayed foam inside I was shocked to see all the tiny pin holes. When I dug up my first underground install it was all filled with water and mud. I was losing a huge amount of energy to the dirt. Yes... too bad you discovered this site after the fact, but you'll get lots of great help here.

 

[Karl_northwind]

it looks like you may need return protection, and probably need a primary loop on the boiler from which you pull secondary loops to the house, garage. that will keep the boiler stirred, and reduce the chances of thermal shock. might be a good application for a taco bumblebee. it'll ramp up when the loops start calling, but keep the boiler mixed running on low when heat loads are not calling.

for starters, I would connect the attached garage in-floor as a secondary as it is, but right after the forced air coil in the flow loop.

you're definitely hampered on the size of the underground pex. you could for now go to a larger circulator in stead of the 2699, maybe a taco 2400-50 or so (you could also add a second 26-99 in-line and remove it if you replace or upsize the underground). the circular alone is a bandaid solution though, you need bigger pex underground for those distances.

If I remember the operation of the G-200 right, if the boiler is at full fire and the water temp goes down too far, it will think the wood is exhausted and shut down. the short primary loop mixing at a relatively high flow rate will help that, as well as provide some moderate return protection.

and also: Plumber does not necessarily mean knowledgeable in boilers.

karl

 

[slowzuki]

It sure seems to me that the house zone is pulling water from the Taco Mixing Valve, going around the boiler. That's the only way I see how the cast iron suction feeding the house zone pump is cold while the boiler high temp is kicking on.

I think people missed the note about the T's and are taking the drawing to mean 4 connections to the boiler. The mixing valve is drawn odd too, is this the actual valve orientation in the install? I would expect the mixed leg discharging into the radiant load in the garage.

 

[maple1]

Pictures would likely help quite a bit.

 

[IACG]

It sure seems to me that the house zone is pulling water from the Taco Mixing Valve, going around the boiler. That's the only way I see how the cast iron suction feeding the house zone pump is cold while the boiler high temp is kicking on.

I think people missed the note about the T's and are taking the drawing to mean 4 connections to the boiler. The mixing valve is drawn odd too, is this the actual valve orientation in the install? I would expect the mixed leg discharging into the radiant load in the garage.

I'm going to take a look at the orientation of the mixing valve. Likely I just drew it wrong. Looking at the diagram I put a comment on there saying that the back-up electric heat source in the attached garage is not going to work the way it is shown there. Maybe I just drew it wrong. I also noticed a mistake on my measurements diagram. The distance from the garage to the exit of the pipe from the house is not 5 3/8"... I messed up and did not type in the right size. That one measurement is the actual size of the drawing. Sorry for the confusion.

 

[IACG]

Here are some pictures of what I've got:


(Above: This is at the switch over from 170' coming from shop into the house. The Ts and valves were for the addition of a small floor heat loop in the future. (yeah right!))

 

[maple1]

I would be nervous having my near-boiler piping in pex like that, would feel much better with copper or black iron. And not 100% sure from the pic, but that looks like the kind of underground piping that might end up sending a lot of your heat into the ground eventually - are both lines together in the same cavity?

Is this a pressurized boiler/system?

 

[Smoke Signals]

first thing I see is in pic #3, there is a by pass valve open. I will look a more.

edit: ok, after looking at the drawing I see why the by bass is open.