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

[Smoke Signals]

Can you post a pic of the side arm?

 

[Smoke Signals]

What is the cord hanging down in pic #4, that's not for the circulator is it?

 

[slowzuki]

Thanks for pics, helps a lot, I was mistaken about the connections.

Ok so lots of people are hung up on the details of the piping runs and flows but there is a more basic problem, we can't be getting boiling and high temp shut down while having cool/barely warm to the touch water coming out the supply connections. The fire tubes are hottest at the bottom of this boilers tank so it can't stratify while being fired even with no loads/flow.

You have no return protection for the boiler and both loads are leaving slabs so you can be dumping very very cold water straight back into the boiler not a short term problem for a gassifier type boiler but a longer term issue for lifespan. Ignore for now.

At the flows you mention in the loops in parallel, you can't have boiling in a 110 kBtu boiler while dumping almost 7.5 gpm of 15 C slab return water into the top of the tank unless your boiler is low on water. The heating load is just so much larger than the boiler output it can't boil it.

As an example, if you are boiling at 212 F and getting 60 F water back from the slabs, at about 7.5 gpm combined flow, you need 570 kBtu input to keep water temp up, 5 times the rated output of your boiler, you'll never keep the water temps up to that 212 F.

Your cold slabs both continuously calling for heat should be overwhelming your boiler in the current config. Improving flow in the feed to the house right now will just expose the boiler to more load until that slab starts coming up to temp.

 

[heaterman]

Look at the "sticky" up at the top of the boiler forum here titled primary secondary .......

Doing that for the garage indoors and adding a dedicated circulator for that area will help the flow situation a bunch.
Right now when your garage zone is calling for heat, all the flow in that loop is diverted through the floor along with everything else. I'd guess you're less than 2gpm at that point. Running the garage as a secondary off the main loop would be relatively easy to do and not overly expensive

You don't have many good options given the loop configuration and the 1" pex

That loop really needed 1-1/4" in the first place.​

 

[heaterman]

"Plumber does not necessarily mean knowledgeable in boilers."
karl[/quote]


Sad to say but what Karl said there is true in a great majority of installs. Licensed or not.
I'd say the percentage of installation we encounter which are just plain bad is close to 80%. I swear most OWB installers, and dealers for that matter truly believe there is no reason for anythinglarger than. 1" tube. They seem to have the notion they are in some kind of magic zone where the laws of physics do not apply.

Here's the tell on your installation.....
Ask the dealer, and then the installer to calculate the head in that house/garage loop. I'll wager you get a deer in the headlights look.

Btw, I believe Karl is right about the automatic shutdown on your boiler if the water temp fails to rise. It thinks the fuel is gone because it sees no temp increase and shuts off the fan.

So.
1. You need a boiler protection device to keep boiler temp at 130-140. That's going to mean not allowing all loads on at the same time so additional controls will be required.
2. Separate the garage loop as a secondary circuit off the main 1" going to the house.
3. As Slowzuki said, if all your zones are calling, there is no way the boiler is large enough to service that load. (Refer to item 1)

 

[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.

Thanks for pointing out my mistake on the schematic. I drew the valve in the wrong direction. I've updated the schematic on the post above.

There are 4 connections to the boiler. I have pictures up now to make sure everyone understands.

 

[IACG]

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?

Not pressurized.

 

[IACG]

Can you post a pic of the side arm?

In the picture I have the valve above the tank shut so that I'm not cooling the water in the tank. The pump was circulating cool water.

 

[IACG]

What is the cord hanging down in pic #4, that's not for the circulator is it?

The pumps were wired in temporarily by the installer. I was going to get them done correctly yet, but I'm holding off now until I know how many pumps I will actually need.

 

[slowzuki]

I'm just gonna pick on a couple of things:

RE 1. - return protection for boiler doesn't mean you have to manage loads, but managing loads certainly helps your control and comfort.
RE 2. - The house garage loop is a secondary circuit. The bypass acts like close spaced T's. The 1/2" pex in slab will only have very very small induced flow while main loop operating as is plumbed UNLESS the bypass is closed. I'm assuming the bypass valve is there to aid in purging the pex in the floor.
RE 3. - Sometimes when bringing slabs into service after being unheated, you just have to wait. If you have return protection you can maintain limited service of other loads or assign priority to the house loads which is what heaterman is talking about in 1. If you don't have return protection, load priority won't matter.

General comments:
Folks are picking on the 1" loop and yes its not ideal especially with all those fittings BUT if the boiler side of things is set up right, you are sending water to loads in the right sequence with the load requiring lowest water temp last. Because this generates a large delta T, a lot more BTU's can be moved for a given GPM going to the house than what some folks systems can do designed using a low delta T. Doesn't cause the main problem with the boiler.

"Plumber does not necessarily mean knowledgeable in boilers."
karl

Here's the tell on your installation.....
Ask the dealer, and then the installer to calculate the head in that house/garage loop. I'll wager you get a deer in the headlights look.

Btw, I believe Karl is right about the automatic shutdown on your boiler if the water temp fails to rise. It thinks the fuel is gone because it sees no temp increase and shuts off the fan.

So.
1. You need a boiler protection device to keep boiler temp at 130-140. That's going to mean not allowing all loads on at the same time so additional controls will be required.
2. Separate the garage loop as a secondary circuit off the main 1" going to the house.
3. As Slowzuki said, if all your zones are calling, there is no way the boiler is large enough to service that load. (Refer to item 1)[/quote]

 

[brant2000]

In the picture I have the valve above the tank shut so that I'm not cooling the water in the tank. The pump was circulating cool water.

Wow, that's a big sidearm. I heat mine with a very small sidearm that's about 16" long. I also didn't notice at first, but you really shouldn't have your sidearm and HX in series (or if you did, you would probably want them in reverse order). It may be one of the lower items on the list of things that need modified, but that's something else to consider.

 

[James Reimer]

Speaking to a troubleshooting rep for Heatmaster, the G200 is very sensitive to supply/return flow rates. Apparently there are baffles and manifolds inside the boiler that direct cold water to certain places. If the flows are not at least 14 GPM there is a stratification issue inside the boiler and the supply water will never get hot while the top of the boiler will boil over. Having low flow and a high delta T like this scenario is, it will only exacerbate the problem as the cold water will fall to the bottom of the boiler and cause extreme stratification.

In typical boiler designs with storage stratification is your friend, but in this model of boiler the supply and return are located closer together in the middle of the water jacket. This is a unique situation for this model of boiler that doesn't happen to other manufacturers that have the supply at the top and the return at the bottom.

To resolve the issue he needs to get the flow rates up with a secondary mixing pump, or make some plumbing adjustments and add another pump for higher flow rates.

 

[maple1]

Sounds like you need a boiler bypass loop - which should also be able to be set up/controlled to provide boiler protection. Which I guess is what the 'secondary mixing pump' is. Also sounds like a unique boiler design - interesting.

 

[brant2000]

This is a unique situation for this model of boiler that doesn't happen to other manufacturers that have the supply at the top and the return at the bottom.

Forgive me if this sounds ignorant, I have no knowledge of Heatmaster or this particular boiler, but this is a basic tenant of thermodynamic design. There's a very good reason that coolant always flows through a car engine from bottom to top, and opposite through the radiator. This sounds like a very poor design.

 

[Karl_northwind]

it uses the principal of a counterflow heat exchanger, which is basic thermodynamic design. the return top supply bottom keeps the boiler mixed. Just my $0.02

IACG: is this an indoor installation? just checking on the lack of insulation on the lines, and the obviously exposed temp sensor on the line in the foreground of the boiler rear photo.

@brant2000: as I understand it, the flow patterns in auto engines also are designed to keep the air elimination function at the top of the radiator.

 

[slowzuki]

Based on what you're saying there is a problem with stagnant areas in the heat exchanger boiling while cold water bypasses that area despite the baffles/manifolds fix they tried? Their graphic of the inside of their boiler looks like a conventional fire tube hx although the sump area of the tank is pretty tight. Stratifying isn't the right word to use but I see what you mean.

Speaking to a troubleshooting rep for Heatmaster, the G200 is very sensitive to supply/return flow rates. Apparently there are baffles and manifolds inside the boiler that direct cold water to certain places. If the flows are not at least 14 GPM there is a stratification issue inside the boiler and the supply water will never get hot while the top of the boiler will boil over. Having low flow and a high delta T like this scenario is, it will only exacerbate the problem as the cold water will fall to the bottom of the boiler and cause extreme stratification.

 

[tom in maine]

In going through two pages of answers, the simple answer is that you still have inadequate flow in the system. If the boiler requires 14gpm, I think I can guarantee that there is no way this system as plumbed will ever do that.
This system would greatly benefit from a primary/secondary plumbing design, separating the garage from the house, putting them both in parallel.
A flow meter or two would be appropriate as well.

 

[James Reimer]

Based on what you're saying there is a problem with stagnant areas in the heat exchanger boiling while cold water bypasses that area despite the baffles/manifolds fix they tried? Their graphic of the inside of their boiler looks like a conventional fire tube hx although the sump area of the tank is pretty tight. Stratifying isn't the right word to use but I see what you mean.

Correct. The stagnant area directly on top of the firebox boils when the fan is running while the rest of the boiler doesn't get up to temp. This is due to inadequate flow rates for this boiler.

 

[cpeltier]

Speaking to a troubleshooting rep for Heatmaster, the G200 is very sensitive to supply/return flow rates. Apparently there are baffles and manifolds inside the boiler that direct cold water to certain places. If the flows are not at least 14 GPM there is a stratification issue inside the boiler and the supply water will never get hot while the top of the boiler will boil over. Having low flow and a high delta T like this scenario is, it will only exacerbate the problem as the cold water will fall to the bottom of the boiler and cause extreme stratification.

In typical boiler designs with storage stratification is your friend, but in this model of boiler the supply and return are located closer together in the middle of the water jacket. This is a unique situation for this model of boiler that doesn't happen to other manufacturers that have the supply at the top and the return at the bottom.

To resolve the issue he needs to get the flow rates up with a secondary mixing pump, or make some plumbing adjustments and add another pump for higher flow rates.

I've seen older combination boilers that stratify like this and require a small pump (Taco 007 or equiv - almost no head loss) that simply recirculates between the supply and return to provide mixing within the boiler. This pump would run whenever the fire is burning. With all of the PEX in this system it may be easy to try.

 

[Clarkbug]

Why not hook that pump up in series with the existing one as a troubleshooting measure? Might get some more flow moving until more permanent solutions can be found...

 

[maple1]

In going through two pages of answers, the simple answer is that you still have inadequate flow in the system. If the boiler requires 14gpm, I think I can guarantee that there is no way this system as plumbed will ever do that.
This system would greatly benefit from a primary/secondary plumbing design, separating the garage from the house, putting them both in parallel.
A flow meter or two would be appropriate as well.

I am thinking that if a boiler requires that much flow through it when burning (and it sounds like the case here), it should have and come with a pumped bypass loop to ensure it. I don't have great exposure to a lot of systems - but 14gpm is sounding kind of on the high side for system flow, and more often than not a typical system won't flow that much. I could be wrong on that, but mine flows less than 10. What would a typical range of system flows be?

 

[Karl_northwind]

14 gpm in a typical 200,000 btu boiler system isn't out of the ordinary at all.
200,000 btu at a 30 degree delta T= 13.5 GPM.

 

[cpeltier]

I am thinking that if a boiler requires that much flow through it when burning (and it sounds like the case here), it should have and come with a pumped bypass loop to ensure it. I don't have great exposure to a lot of systems - but 14gpm is sounding kind of on the high side for system flow, and more often than not a typical system won't flow that much. I could be wrong on that, but mine flows less than 10. What would a typical range of system flows be?

14GPM at a typical 20F delta T is 140 BTU/hr. That's a lot of wood to burn and heat to move without a bypass loop, primary/secondary loop or storage system. The way this system is setup now his delta Ts could be much higher with the sequential loads finishing with radiant heat. I would add a short primary loop feeding the secondary loop with a high head circulation pump (Taco 009 or 011) or another pump in series as already suggested. The run length is so far that getting over 10GPM will be next to impossible. The fan coil may also have a significant head loss at these flow rates and may need a bypass zone valve.This is a non-pressurized system so i assume you must use non-oxidizing and more expensive pumps.

 

[slowzuki]

Trying to force more gpm through the long loop is expensive if you don't need the BTU's in the house but just need mixing. Cheaper to circulate at low head through the boiler like other posters mentioned earlier.

What a fundamental problem to have in the boiler though, you'd think they would have picked that up. With the extra ports on the back maybe they anticipated one set just for a mixing pump.

BTW its not really a 200k boiler, only something like 111k if you read the literature.

 

[IACG]

The dealer came back with some suggestions today.

1) Put a larger pump (Grundfos 26-150) the equivalent of 2 -2699’s on the line that runs to your house. Take the 26-99 that is currently on the line and move it to the line that runs your floor heat in your shop.

2) Add an additional 26-99 on the return line from your house and replace the 15-58 that is running your shop floor with a 26-99.

3) Add a 26-99 to the bottom of your stove where the 1” drain valve is. Attach the pump to both of your return lines essentially creating a circulating loop.

He figured the second option was best option. He says that the two smaller pumps working together would be more effective than one large one. With the addition of that pump and the upgrade of the 15-58 he says there should be enough flow to prevent thermal layering.

I asked him about the thermal shock having such a large Delta T. He says that it is not a problem. He contacted the manufacturer and they too say it is not a problem to send back really cold water. The told him, "The only way that it could potentially become an issue is if you had very cold water ( close to freezing continuously running back to it.) With the way its set up the water that runs back to the boiler instantly mixes with the other 150 gallons that are already in there, so it is highly unlikely that it would ever become and issue."

I was wondering if this option would be better:

Running a small pump on Ts from the shop loop. There are 1" Ts already mounted on the supply and return of that loop. Because there would be virtually no head in this loop enough flow would not be a problem. I was just not sure if the way the Ts are set up if I would this pump draw too much flow away from the shop loop. This does not solve the large Deta T issue, but the dealer assures me that I would be wasting my money buying a mixing valve and such to warm the return line from the house. In fact, he figures the added resistance would cause even more of an issue.

So what do you guys think of his suggestions (or my idea?)

Thanks for all your advice.