Upper floor is much warmer than ground floor

ineedheat

Hello,

I got a new buderus boiler installed in the house I moved in. I am facing an issue where the second floor is always above 75 degrees and there has been no need for thermostat to call for heat. The first floor is set at 70 and occasionally calls for heat. I am wondering if it's just hot air rising up or is there a zoning issue with the pipes. Can someone help? I opened all the windows and temperature dropped to 69. But overnight it crept up to 76 even when thermostat was turned off?!

Also, I have heard the boiler start up even when no thermostat is calling for heat. Probably because the water in the boiler has become cold. Is there any benefit to put a layer of insulation around the boiler to maybe save some heat loss and oil consumption? Appreciate any help.

Edit- I forgot to mention. There are 2 zones in the house. One zone with a pump for the first floor and another One with a pump for the second floor. It's the second floor that remains very hot. 

JimP

You may need a flow control device. The warm water may be circulating to the upper level by gravity.

ineedheat

So the hot water can still flow through a pump that's not on? I am assuming that if the thermostat is not calling for heat then the pump will not be turned on. 

Canucker

ineedheat said:

So the hot water can still flow through a pump that's not on? I am assuming that if the thermostat is not calling for heat then the pump will not be turned on. 

Depends on the set up, but unless there is a flow check installed, hot water absolutely can flow through a pump that isn't running

EBEBRATT-Ed

@ineedheat

Some systems have a "flow check valve" this could be a separate valve installed near the pump or it could be a check valve inside the pump.

The purpose of this valve is to prevent water circulation by gravity when the pump for that zone is off.


Here is the test, keep you second floor thermostat turned down low or off. When you here the boiler running for heat on the first floor check your second floor radiators and see if they are warm

ineedheat

Thank you all.
Yea it seems like second floor radiators are warm even when only first floor pump is turned on. Is this all hot water circulation without pump due to gravity or do you think there could be a some kind of internal connection such that first floor pump is somehow driving the flow through second floor too?

EBEBRATT-Ed

@ineedheat

Yes, when the FF pump runs you can get flow in another zone if that zone has a defective check valve/flow control valve. This is a common problem. You can also just get gravity flow if the boiler is warm and the FF pump is off.
?
Why not post some pictures of the boiler and the piping around the pumps

ineedheat

The pump on the left is for second floor and the middle pump is first floor. The pipe on right is first floor return and the pipe in middle is second floor return. 

Thank you.

ineedheat

ineedheat

pipes from boiler to board

ineedheat

ineedheat

Also if someone can guide me on insulation for the boiler? I hear the boiler start up many times when no thermostat is calling. Is the a insulation jacket that I can get for the boiler and pipes around it to preserve heat. Or is that not very helpful?

EBEBRATT-Ed

The boiler is probably starting due to the gravity circulation. I don't see any flow check valves in your piping. So either the installer forgot to install them or your circulators have internal check valves inside them (most likely)

The writing on the pump is too small to see. Look at the name plate on the pump and see if it has "IFC" in the model #

You will have to get a service tech in to replace the check valve in the pump if you want to stop the gravity circulation

ineedheat

Pump for first floor.

ineedheat

Pump for second floor. 

I see the IFC is missing in the pump for second floor. So you think if the pump for second floor was an IFC pump, it would stop any flow due to gravity or any pressure difference and only allow hot water to flow when thermostat cals for it?

And all of this could explain the water in the boiler dropping it's temperature to 120 and thus the boiler strata up to heat it as it still detects water movement?

JUGHNE

You could turn the 2nd floor stat all the way down and then close the valve on the 2nd floor pump. (that would do the same function as the flow check....just be sure that pump does not run with the valve closed)

See if you still overheat.

It is possible to still get gravity flow up to the second floor thru the single return pipe. The hotter water can rise in the center of the pipe and as it cools, that cooler water comes down the outer edges of the pipe interior.
As it cools more the more gravity flow in induced.
This is rare but can happen.

ineedheat

Yea I hear metal sounds from baseboards even when when the thermostat is not on. Maybe suggesting flow throughout. 

I have turned it off and the thermostat is off. So we shall see if I still overheat.

EBEBRATT-Ed

@ineedheat

You can see for yourself that the second floor pump has no flow check in the pipe nor does that pump have a flocheck built in. The first floor pump has an internal flocheck.

As I mentioned in my first post you have a flow check problem. If you want it fixed you have 2 choices.

(1) Replace the 2d floor pump with a pump with an internal flow check

(2) install a seperate flow check in the second floor pump piping.

#1 is probably less $$$ if you know how to drain and fill system and sweat pipe with a torch

#2 is a lot easier but cost more $$$

Chances are someone who didn't know what they were doing installed the wrong pump for the second floor or it was replaced at some point with a pump with no flow check

ineedheat

Thank you all. Such helpful and insightful explanation. 

After fixing all this, do you believe that the boiler won't have as frequent starts and if it still does, should I put insulation on the boiler and pipes?

JUGHNE

How do you heat your water for faucets, showers etc?

It sounds like you maintain a "hot" boiler, that is always kept hot waiting to deliver heat.

IMO, you should have a "cold" boiler, that is, it fires when a tstat calls for heat....or if you have an indirect water heater tank.

That boiler should heat up quickly on a call for heat.

As far as the insulation, any heat lost from boiler jacket and piping is still in your house. Perhaps keeping the basement and the bottom side of your floor warm is to your advantage.

I am not familiar with your zone control box on the wall by the pumps, but my best guess this change from maintaining hot boiler, to on demand only, can be changed in there.

Other wallies please correct me if needed.

EBEBRATT-Ed

Looks like a Tekmar control, cant read the model. You just have to fix the "flo ckeck " problem and then go from their. The Buderus boiler are usually well insulated

JUGHNE

Also if you continue the "hot" boiler condition it is more likely to have the single gravity upward flow in the return line. Even with the pump valve off or a flow/check installed on the supply side.

This test if done overnight, may let you know.

ineedheat

I shut off the valve overnight and the pump was off. There was no heat the whole night and temperature was 68 throughout night. I think swapping the pump for one that has flow control should solve the issue. I believe buderus boilers are cold strat boilers so I don't think it's starting up to maintain a temperature. I have a separate water heater that provides domestic hot water. 

I will skip adding more insulation as you all suggested, the heat is not "lost".

JUGHNE

With both tstats set to not call for heat does the boiler stay cold/cool?

ineedheat

With both tstat off, I have heard the boiler go off. And when I check it's because the temperature of water is below 120. I am posting a picture of the set up on the boiler and maybe some settings can be changed on it to make it more efficient

ineedheat

And this is after opening the cover.

ineedheat

The setting are

High limit-180
Low limit-120
Economy-off

EBEBRATT-Ed

@ineedheat

Go to the Hydrolevel site or to Supply House .com and download the instructions for that control.

You low limit set to 120 is keeping the boiler on. You can turn it off by disabling the low limit if you want.

This does not mean the circulator that is missing the check valve is ok. That still needs to to be done

ineedheat

@EBEBRATT-Ed
Thank you. Yes I agree the check valve issue is separate and will have to be addressed.

I was able to understand the instruction for hydrolevel and it seems pretty straightforward to reduce the low temp limit or turn it off. Can I turn off the low limit without causing corrosion or any damage to the boiler? I know buderus boilers are more tolerant to thermal shock. Anybody have experience with buderus G215 boilers with low temp limit turned off?

EdTheHeaterMan

You can add a IFC to most existing Taco 007 pumps made today. (Cant' add it to older pumps because the housing was not designed for the IFC) buy this part online https://www.supplyhouse.com/Taco-006-047RP-IFC-Replacement-Kit-for-Select-Taco-00-Series-Cartridge-Circulators Because you have isolation valves you an make the repair easily. Then get a sticker and put it on the pump

JUGHNE

Is this a new install for you?
Did you ask the installing company about your problems?

EdTheHeaterMan

So you don't use more fuel than necessary, go inside this control
Then set the low limit dial to OFF and remove jumber B (if you have one)

Gilmorrie

One of the pump's nameplate has "inegral flow check". The other pump's nameplate does not. Both pumps need a flow check, either integral or external. That is the problem.

ineedheat

@EdTheHeaterMan @JUGHNE

Yes this is a new install. The company is sending over technicians to take of care of the check valve tomorrow. I will ask them the same questions tomorrow and have the low limit changed to a more efficient setting. I wanted to get some knowledge and opinions before so that I can make an informed decision about things. I appreciate the help from all of you.

So, I understand that the low limit can be safely turned off for this boiler and also address the check valve at the pump for second floor.

JUGHNE

It looks to be a pretty good install, but they just overlooked some details.
They should of had a senior tech come check things out before billing for the job.

What does the exhaust flue/chimney set up look like.....before we add more good install comments.

The oil burner people here could give that a good looking over....I am not one of them.

ineedheat

@JUGHNE

JUGHNE

So these are both oil burners?
I see no barometric dampers that are usually on oil burners.....IDK if needed or not.

Is there a new liner up the old chimney?

Can you get a better shot of where it connects in the wall/chimney?

It looks to be running down hill into the wall??

ineedheat

Left is an oil water heater and right is an oil boiler for heating only.

EBEBRATT-Ed

@ineedheat

Where the flue pipe enters the chimney it is not sealed to the chimney as it should be. Also as @JUGHNE mentioned the lack of barometric dampers the Buderus may or may not need one.

The boiler can be run as a cold start with the low limit turned off IF your TECHNICIAN determines that it can come up to temp quickly to avoid flue gas condensation. If not the low limit needs to stay on

ineedheat

Thank you @JUGHNE and @EBEBRATT-Ed.

I will find out about this tomorrow.

EdTheHeaterMan

Another consideration is the capacity of the chimney. Each vent connector (smoke pipe) should have its own barometric draft control. this means that you should have one for the water heater and another one for the Buderus boiler. Then have the technician test for proper draft with each burner operating separately and with both burners operating at the same time. That is 4 different tests. 1. HW by it self and 2. HW with the other burner operating 3. then Boiler by itself and 4. boiler with other burner operating.



Also check the venting tables on NFPA 31 for the chimney capacity. If the chimney is to small to handle both the burners operating simultaneously, then a priority relay can be added to shut down the heating boiler oil burned when the DHW burner is operating.