Mostly toasty feet, but I have questions!

LauraL · November 9

Can someone explain to me how the flow meters work on my electric hydronic in-floor heat system? It is all new to me, and a brand new system. Sadly my installer passed away before he was completely satisfied with the way the system was working, so I can't ask him.

I have a couple of zones that are calling for heat, the boiler kicks on for around 30-40 seconds, then off for a minute or so, then back on. This may go on for hours. Should it be cycling this quickly, and for so long?

Could this be because the flow meters on those zones need to be adjusted? How do I adjust them? Should the spring-loaded black line move as I turn the knurled collar at the base of the meter? Or does the black line move in response to something else? (I have tried turning the knurled collar and see no immediate change.)

Below are pictures of my system for background. The boiler and small manifold are in my utility room, the larger manifold is in my pantry at the other end of the house. Another thing I don't understand is there are 8 actuators and flow meters, but only 6 thermostats in the house. Why might that be?

Thank you in advance! I can't wait to find out more about this system!

mikeapolis · November 9

Sorry to hear about the passing of the person who installed the system. Looking at the Temp/Pressure gauge I can't tell what the water pressure is at. Can you confirm that from the dial on the top of the boiler. Sounds like you have two loops feeding one zone, maybe to a living room or large space.

hot_rod · November 9

the system could need to be purges. With all the thermostats turned up, flow meters should read around .5 gpm.

If your boiler has ODR outdoor reset, that should be set up so the boiler temperature changes based on outdoor temperature. That would help with the short cycling.

LauraL · November 9

EdTheHeaterMan · November 9

Looks line the high limit or operating limit is set at 130°. Don't let the label fool you. That is not the desired temperature. That is a switch where the electric will turn off when the water temperature gets there. Watching that temperature gauge during the operation will give a clue as to how the boiler is operating.

EdTheHeaterMan · 12:07AM

The actual model number of the boiler will reveal its capacity. That will be much more helpful in solving your short-cycling situation.

If a boiler is turning on and off that many times during a heating season, you may find that its normal service life could be reduced to as little as five years. If you can get it to cycle only once or twice an hour, that boiler could last 20 years or more.

You need to find a competent professional to make these adjustments. Try contacting the boiler manufacturer for the name of a factory-trained professional, or check with the supply house where the boiler was purchased.

You can also click here to Find a Contractor in your area at the top of this page.

Jamie Hall · 12:41AM

The flow meters will help you balance the heat between various spaces — up to a point. If some areas seem to be a little warm, you can dial the flow back a bit. Conversely, if some areas are too cool, you can increase the flow to those area. How much you can adjust that depends a lot on how the system is laid out.

As to the cycling — if this were a fuel fired boiler, I'd not care for it. But electric? Probably doesn't hurt much — although if there is a way to adjust the operating temperature you might want to investigate that.

hot_rod · 1:14AM

that is a fine little boiler. If it is the M series it modulates based on the heat load. Unless it is grossly oversized, it should rev down for just a single zone.

I don’t see that model with ODR?

psb75 · 1:31AM

The black line in the flow meter should move down as the flow increases. In the close up picture, the meter on the left reads .6 gal/min. And the right one reads 1 gal/min.

LauraL · 1:35AM

Here is the tag with model number on the boiler. I do not know if it is an outdoor reset boiler. The installer initially bid a boiler with outdoor reset, but when purchase time came around that boiler was no longer available and this one is the substitute.

hot_rod · 1:55AM

That is about a 61,000 btu/hr boiler. What size home is this heating?

Do you have a total of 8 loops, 5 on one manifold, 3 on the other?

. Or are there more manifolds?

M2 indicated a modulating boiler, the manual would indicate how low it can modulate

Looks like that boiler wants 5.4 gpm minimum, .3 gpm per kw. With only that 3 port manifold operating You would not get 5.4 gpm through the boiler.

I’m wondering if the boiler is oversized?

hot_rod · 2:04AM

more info on your specific model.

Looks like the 18 kw modulated down to 47,000 btu/ hr? Bottom line, top chart.

If so that is not low enough for your small zones, hence the short cycling.

Let’s find out more about what the home actually needs.

It may be possible to disconnect one of the elements and downsize the boiler. Check with Electro on that. I have done it on other brands.

The bottom notice indicates the cause of “rapid stage cycling” Again lack of adequate flow and load.

hot_rod · 2:09AM

more info from the Electro website. It does mention ODR.

Dave Carpentier · 2:41AM

There does appear to be 2 240v breakers on the face…

Likely can turn one off and unit will still work.

Solves the btu clog for now, but once really cold hits you might need the 2nd element.

Elements are probably replaceable, perhaps lower wattage can be swapped in ?

LauraL · 3:43PM

Wow! This is a lot of information! I'll try to add what I think I know:

All of the manifolds are shown, 8 loops total. I believe I have figured out that three of the loops are connected to one thermostat, the Living, Dining, Kitchen. It is a large open area. The whole house is 2700 sq ft. Concrete floors.

Two zones seem to give me trouble, and indeed they are small areas, and located at the two far ends of the house. These seem to be the ones that cause the continual short cycling. When either of them is calling for heat (and none of the others are) is when I notice the short cycling, which can go on for hours, and they never get up to the set point on the thermostat! Eventually I turn the t-stat down, just to stop the cycling.

This morning, 6-7 am, most all the zones are calling for heat at the same time, and the black pump just below the boiler is reading 7 ft (normally is just has three little green lights circulating around which I assume means it is not actively pumping). The boiler is staying on for several minutes at a time (5 or more). Boiler temp is 120 degrees. This all seems to me like a more proper operation.

I have noticed when the boiler is short cycling the pump is in the little-green-lights-circulating mode, so lack of circulation could be the problem.

Mostly toasty feet, but I have questions!

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