Boiler for baseboard heat cycles on / off all day

jackheney

Hi,

I bought my house a couple years ago, it has a Buderus Legamax Plus GB142 fed baseboard heat system. Let me preface all of this by saying I know next to nothing about heating systems.

I noticed today that the boiler was constantly cycling on and off, and the temperature reading on the control panel would rapidly drop from 160 degrees to about 110, then cycle on and heat back up. It also didn't appear that the baseboards were heating up, especially on the upper floors.

I suspected water wasn't properly circulating, as the pipes leading to the baseboards weren't particularly hot...there's a Taco 221 Flow-Check in the system, and just by touching all the pipes in the system it seems like that was about the place hot water was getting stopped. I loosened the thumb screw on top, and after about 5 minutes it seemed like circulation was improving, the boiler temperature stabilized and it stopped cycling so much.

My question is whether I should tighten the thumb screw on the flow-check again. I'm not sure I *fully* understand what this is for, and the boiler is only used for heat (I have a separate hot water heater for domestic purposes).

Thanks in advance!

Jack

Ironman

Whats the pressure reading on the boiler gauge?

jackheney

P17

Ironman

Is it a single zone system?

jackheney

There's only one thermostat, but 5 valve-controlled baseboard zones that were tuned by the previous owner to try to balance heat distribution throughout the house

EdTheHeaterMan

Here is a booklet you may find interesting. It has easy to understand technical explanations of basic concepts used in your heating system. http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf

The info about what the valve you opened is used for, is on page 9 column 2

I suspect there are other issues that are giving you poor heating distribution problems and short cycling. Could you take a picture of your heater from far enough away so we can see all the connecting pipes and maybe those balancing valves (from different points of view also)

jackheney

Pictures attached...and thank you both so much for taking a bit of your time to look at this (and the PDF you linked is super-helpful).

Is your thesis that I've got *some sort of* circulation problem that is preventing the weight in the flow-check from being pushed up, and I've temporarily mitigated that by loosening the valve at the top?

Ironman

Well, I can’t quite see how everything is connected, but I do see the following issues:
1. The circulator near the flow check is improperly mount in the vertical position which will cause it to fail. This may be your problem.
2. The way those ball valves have been used to throttle the loops is a mistake and restricting flow which will cause the boiler to short cycle.
3. The way that the smaller zone is connected at the low loss header is incorrect, but may or may not be a problem.
4. The way the supply line is connected into the bull of the Tee after the flow check is against code and proper piping practices.
5. The SafeGaurd low water cut off is for steam boilers and has a 10 or 20 minute shut off function to prevent the water from foaming in a steam boiler.

I believe your main issue is lack of flow from either air binding or a bad circulator.

Your last pic is of a gas manifold.

jackheney

Thanks Bob, lots of useful stuff. I have a couple questions if you have a minute...

1. I'm assuming you're talking about the circulator in the third picture?
2. You mean in the last picture? I see the gas manifold (I think you reference this at the bottom), but up above that are the loop control valves, is that what you're talking about? I can switch them all to wide open if you think that will help.
3. I'm not sure I know what you mean by "the smaller zone". Can you clarify?
4. I can have a plumber / HVAC tech come out and solve that (I hope)
5. Does this mean it's unnecessary? Or that it may be contributing to the problem?

Is there a way for me to isolate whether it's air binding or the circulator?

Thanks agin for all the help!

jackheney

RE: #3, I forgot that there's a radiant floor in the mudroom that is a second zone...I see what you mean on that one.

ChrisJ

Ironman said:

Well, I can’t quite see how everything is connected, but I do see the following issues:
1. The circulator near the flow check is improperly mount in the vertical position which will cause it to fail. This may be your problem.
2. The way those ball valves have been used to throttle the loops is a mistake and restricting flow which will cause the boiler to short cycle.
3. The way that the smaller zone is connected at the low loss header is incorrect, but may or may not be a problem.
4. The way the supply line is connected into the bull of the Tee after the flow check is against code and proper piping practices.
5. The SafeGaurd low water cut off is for steam boilers and has a 10 or 20 minute shut off function to prevent the water from foaming in a steam boiler.

I believe your main issue is lack of flow from either air binding or a bad circulator.

Your last pic is of a gas manifold.

Hi Bob,

You're thinking of the Cycleguard.
The Safeguard, unless it's recently changed does not do this.

Ironman

ChrisJ said:

Well, I can’t quite see how everything is connected, but I do see the following issues:
1. The circulator near the flow check is improperly mount in the vertical position which will cause it to fail. This may be your problem.
2. The way those ball valves have been used to throttle the loops is a mistake and restricting flow which will cause the boiler to short cycle.
3. The way that the smaller zone is connected at the low loss header is incorrect, but may or may not be a problem.
4. The way the supply line is connected into the bull of the Tee after the flow check is against code and proper piping practices.
5. The SafeGaurd low water cut off is for steam boilers and has a 10 or 20 minute shut off function to prevent the water from foaming in a steam boiler.

I believe your main issue is lack of flow from either air binding or a bad circulator.

Your last pic is of a gas manifold.

Hi Bob, You're thinking of the Cycleguard. The Safeguard, unless it's recently changed does not do this.

Thanks Chris. Another senior moment.

Ironman

If you’re getting heat from all the BBs, I wouldn’t recommend trying to purge air from the loops yourself. It’s not that difficult once you’ve been shown how, but it’s not so easy to describe without being there.

For now, I’d recommend that you get a HYDRONIC pro on site and let him evaluate what’s going on an fix the circulator that’s installed wrong.

Check the contractor locator above for someone near you.