Can Heating Cycles Be Too Long?

Steve Rockwell_2

I've heard of long run times, but this is ridiculous.

We've had our Ultra 155 for three months now, and love it. Thanks to the pdf that Floyd posted, I have programmed many of the parameters of the boiler, some of them several times as I try to adjust the boiler to our application and weather. The house has never been more comfortable, and so far our gas bills are down 47% over a 3 month period (not weather corrected).

It sometimes short cycled before, but now I wonder if I have gone too far the other way. It essentially never shuts off.

The thermostat is always dead nuts on 69* as set, but the boiler is running virtually all the time. Considering that the temperature is where I want it, is it bad to have the boiler continuously running?

Your thoughts please.

Constantin

Well, let's think about this...

.... you own a condensing modulating boiler, that, IIRC, has a 5-1 turn-down ratio. Thus, it can fire at 20% of its nameplate capacity (139kBTU in) all day long for about 27kBTU net output at 96% AFUE. Given the low output number and the likely heat loss of the home considering the size of the boiler, it's pretty safe to assume that once your home is on the perfect reset curve that the Ultra won't stop running from October to March.

I'd call WM and make sure that 24/7 operation is OK, but I doubt it wouldn't be. In fact, considering how much start-up and shut-down usually wears on things, they might prefer their appliance to run 24/7.

Bill Nye_2

gas bill

the gas bill is down 47% ?? I wouldn't argue about that. Room temp. is perfect? No complaint there either.

Unknown

Condensing/Modulating Boilers Run & Run

I just spent a cold day with the Vitodens I installed a few months back. The boiler never shut off once the whole time I was there. I have been playing with the slope/shift, day & night temp schedules. As the colder weather has now set in, I find that the lead /lag time switch points need to be fine tuned. Amazed to see & hear the dripping from the condensate drain when it's this cold out. Indoor temps are right on the money but boiler just sits on low fire & stays there. Dial on the gas meter barely moves.

Check out the ice on the cage for my vent termination!

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Unknown

Condensing/Modulating Boilers Run & Run

I just spent a cold day with the Vitodens I installed a few months back. The boiler never shut off once the whole time I was there. I have been playing with the slope/shift, day & night temp schedules. As the colder weather has now set in, I find that the lead /lag time switch points need to be fine tuned. Amazed to see & hear the dripping from the condensate drain when it's this cold out. Indoor temps are right on the money but boiler just sits on low fire & stays there. Dial on the gas meter barely moves.

Check out the ice on the cage for my vent termination!

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

Condensing/Modulating Boilers Run & Run

I just spent this cold day with a Vitodens I installed a few months back. The boiler never shut off once the whole time I was there. As the colder weather has now set in, I find that the switch points need to be fine tuned for more accurate Day & Night temp schedules. I have been playing with the slope/shift trying to see how far I can lower the curve without underheating the house. I'm still amazed to see & hear the dripping from the condensate drain when it's this cold out. Indoor temps are right on the money and boiler just sits on low fire & stays there. Only way I can tell it's running is the little green light on the Comfortrol™

Check out the ice on the cage of the vent termination!

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

.

Your system appears to be working exactly as it is supposed to work.

Unknown

Nope

They should last all winter long. (low fire)

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Mitch_4

Look at it this way

It where you put the BTU's you burn. Once the heat exchanger has heated to a point where it transfers heat as fast as it absorbs it, you are putting it in your house. Everytime the boiler shuts off and restarts, the heat exchanger has to be reheated, BEFORE it starts to put it in the space. That is energy wasted, you are sending it up the chimney, not into your h2o. If it keeps your place warm, the bills are low, and it is NOT shutting off, it is running at its finest.

Mitch

Steve Rockwell_2

A Breather

After several days with what appears to be constant firing, it is cycling somewhat.

Obviously I understand that it was designed to run in long cycles, but it did seem a bit odd that it NEVER cycled.

Can you say "micromanage?" Perhaps I should keep my nose out of the boiler room, as it seems to be doing beautifully without me looking over its shoulder.

All is well. Thanks for the input.

Mike T., Swampeast MO

Watch and Learn

Proportional control is so foreign to most of us that we can't understand:

Q: Why is my boiler more efficient when it runs constantly?

A: Only because it is producing just the amount of heat being lost.

oil-2-4-6-gas

> Proportional control is so foreign to most of us

> that we can't understand:

>

> Q: Why is my boiler

> more efficient when it runs constantly?

>

> A:

> Only because it is producing just the amount of

> heat being lost.

oil-2-4-6-gas

.

in Commercial heating i try to set-up the boilers to modulte down to low fire and maintain temp. the less start and stop of most of the motors,starters and electriacal parts last longer and you are more efficient------its like going on the highway in your car for miles flooring it then stopping start-up again and floor it --its much more efficient to maintain speed --a lot of energy is wasting going full out only to stop and go full out again -