Speed question about Taco 007 vs. 0015e3

Rickoo

Oil fired, forced water Peerless cast iron boiler with fin tube baseboards.

I’ve been having an issue with the amount of time it’s been taking (during outdoor temps in the teens or low twenties) to bring the temp up to 68 degrees from a 64 degree nightly setback. (Have posted before about this and other issues.)

Had the service manager from the company who services my boiler come have a look at it. Even though the baseboards seemed pretty warm during operation, he felt it might be the 24 year old 007 circulator. He pulled it to have a look at the impeller to see if it appeared worn. It did not. However, he wanted to try increasing the flow to the affected zone and installed a 3 speed 0015e and set it on high. It’s been about a week or so and it doesn’t seem to have made much difference.

My next plan is to upgrade the attic insulation in my 24 year old home and maybe have a blower door test performed to see if I have excessive heat loss somewhere that could be cost effectively addressed.

Being concerned about possible erosion from the likely unnecessary higher flow, I’d like to turn the circulator speed down to a flow that more closely resembles the older 007. Is this a good idea and if so, is there a speed setting on the 0015e3 that would accomplish this?

Thanks everyone! You folks have been an invaluable resource to me and all the folks coming here for advice!

Dave H_2

The 0015e3 set on medium speed has a very similar performance to the 007.

When you say you have an issue raising the temperature inside from 64 to 68 degrees, what do you mean?

Does is take an ungodly amount of time or is it different amount of time from month to month and hard to track?
Has it always been that way for the past 24 years or is it a recent issue?

Jamie Hall

Simple test. What is the difference in temperature between the supply pipes going out of the boiler and the return pipes coming back? Or if you have primary/secondary piping, the pipes to the system from the low loss header or closely spaced Ts? If that difference is much higher than say 25 degrees F, you need more flow. If it's lower than say 10 F, you need less...

Rickoo

So, it's been taking around 6 hours to bring the house up to 68 from the 64 degree setback with outdoor temps in the teens.

I don't ever recall it taking this long, however I recently retired and am home much more often. Not sure if it's always been this way and I've never noticed? I any case this seems like an awful long time for a 4 degree rise. 

The second floor zone is set on 65 and left alone. We have an open foyer that I'm sure allows the first floor heat to rise to the second.

Zones are each series loops and not primary/secondary. 

I just set the 0015 circ to medium and measured the delta-T.  Finding about 24 degrees but seems like sort of a moving target. I'm measuring with a small Seek thermal camera and trying to pinpoint the hottest area on the black iron piping supply and return piping. I tested about 30 seconds after the burner shut off at high limit. 

Rickoo

By the way, hydrolevel is currently set at high limit of 185. Low at 160. Economy off. 

GGross

It is quite possible that you do not have enough emitters in the space to adequately recover from setback in the timeframe you are looking for. Lowering the heat loss of the building, or adding emitters to the spaces most impacted should get you faster recovery. More flow will only really help to a certain point, as you pointed out too much flow isn't good for the pipes. If you have baseboard you can go through and clean the fins and also make sure there is not a bunch of stuff blocking airflow through the fins.

Dave H_2

I think what may be occurring is what i call "two drivers, one car"

The Hydrolevel is trying to learn the house heating curve, temperature patterns, outside air temp and providing energy savings without sacrificing comfort. I don't know enough about the programming and algorithms of the unit. This is the first driver.

The second driver is the thermostat. If you have ever had two drivers in a car with massive type A personalities, they each have their own way of getting there and they each believe their way is the only right way.

Maybe try to not turn the thermostat back as much. I have similar controllers fighting each other in my house, I turn my thermostat back only 3 degrees only. This 3 degree drop gave me what I wanted (keep the zone off during the night) and the right amount of time to get the heat up to temp.

Rickoo

Thanks.

I have the economy features turned off in the hydrolevel. I'm fairly certain its acting as a dumb aquastat set up this way. However, I fully get the 2-driver scenario. Been there, done that (and will continue to) with my better half.

Don't think there are two few emitters. I have what I believe to be plenty of finned baseboard and the service folks agreed. All as clean as the day (ok, maybe close to) they were installed.

When we built the house it was insulated with R-30 (9.5) inches of blown in cellulose. All of which has settled to likely 6-7 inches on average.

The other thing that has changed is we installed a ducted Mitsubishi heat pump air handler in the attic 2-3 years ago. In total I have 7 supply registers and 4 returns upstairs. All open to the attic ducting. (Which is all properly sealed and as well insulated as ducting can be.)

I'm wondering if I'm losing heat to the attic ducting installed in a cold, ventilated attic? Is there any reason to maybe try covering the supply and returns with something in the winter? We have not been using this air handler zone for heating.

GGross

We need to transfer more BTU/h into a space to raise the temperature 4 degrees in 1 hour as opposed to 4 degrees in 6 hours, heating systems are generally designed to maintain a set temperature all the time, a 4 degree setback is quite large in my opinion, and recovering that in the span of an hour with baseboard will be challenging. many systems are oversized and can recover that without problems, but then they are oversized the rest of the year. Some systems utilize supplemental heat to recover from large setbacks

I am still thinking you don't have the emitters to accomplish this, as we know you have adequate flow, adequate supply temperature etc. The added loss from the new ducts as you pointed out is minimal as it will all be insulated and sealed, and even if it were enough to change things you could overcome that with more heat delivered to the space

STEAM DOCTOR

Maybe problem on the fire side. 

Mustangman

I think you solved the problem. First, your heat loss increased with every diffuser and RA that was cut into the attic space. If you aren't using the heat pump side of your Mitsubishi system, you should have insulated panels for all the returns. 1" ductboard painted black works well on returns. The supply diffusers should be closed. The other thing is the Delta T. He said something about it moving. Depending on what he was using to measure supply and return water. I don't have faith in infrared type. The beam will bounce off of shiny things and will give a false reading. You are looking for 20 degree difference. If its only a 10 degree difference, you may be pumping so fast the BTUs can't jump off. If its a super wide difference like 30 to 40 degree increase the flow. An accurate Delta T is your first move.Your issue could be 2 fold, cold air coming into the space from the attic duct system

GGross

" you may be pumping so fast the BTUs can't jump off" this is not how heat transfer works

Delta T is always a moving target until a heating system reaches thermal equilibrium. unless you are using a pump that specifically controls delta T. A moving delta T is perfectly acceptable, and you would expect it to move while heating the space up 4 degrees

Jamie Hall

Since I suggested measuring the delta T... thank you. And your delta T is fine. Which means that given what you have for radiation and its condition you are putting as much heat into your space as you can.

Rickoo

Thinking bringing my attic insulation up to today's code cant be a bad idea and plan on moving forward with that before summer. Interested if anyone else has a take on the benefit of closing/sealing the supply/return registers on the second floor for the cold season. I have no problem constructing some sort of cover system, but if there won't likely be any real benefit, I won't bother.

Mustangman

Actually it is how transfer works. When we set up radiant loops to a 15 degree delta T It is exactly how you adjust. You can see it happen watching your temperature gauges. If its a really broad delta like 30 or 40 degrees, that makes the return coming back from your 300" loop about 75 degrees. So 2/3 way through your loop, you can't effectivily heat the floor. Speed it up. All your btus won't be used up close to the manifold. You may be sending out 130 and bringing You may be carrying 110 degrees back to the boiler, not double digit lows you had when the flow was too fast. If I am not mistaken, Mr Holohan himself enlightened me on that. Didn't make sense but they he used a story about kids on a bus are like btus in a pipe. they travel too fast, they cant get off the bus so the delta T gets narrower.

GGross

@Mustangman
"they travel too fast, they cant get off the bus "
again that is not how it works, the bus analogy had to do with the passengers being BTU and only so many BTU can fit on the bus. as you increase flow you increase average water temperature (more buses in the analogy), a higher average water temperature will transfer more heat through emitters. With a radiant floor you are limited somewhat because you don't want to overheat the floor, with baseboard you are limited somewhat because if your GPM is too high it is bad for the pipes, with either heating method an increase in flowrate, results in a higher average water temperature which results in a higher heat output to the space. The idea that its too fast and they can't get off the bus is an old misconception that is repeatedly proven incorrect

GGross

Rickoo said:

Thinking bringing my attic insulation up to today's code cant be a bad idea and plan on moving forward with that before summer. Interested if anyone else has a take on the benefit of closing/sealing the supply/return registers on the second floor for the cold season. I have no problem constructing some sort of cover system, but if there won't likely be any real benefit, I won't bother.

Personally I don't think it will help much if the duct in your attic is well insulated (it should be). It might be an easy enough thing to try though, just make sure the unit is off while the returns are blocked if you try it

hot_rod

Mustangman said:

Actually it is how transfer works. When we set up radiant loops to a 15 degree delta T It is exactly how you adjust. You can see it happen watching your temperature gauges. If its a really broad delta like 30 or 40 degrees, that makes the return coming back from your 300" loop about 75 degrees. So 2/3 way through your loop, you can't effectivily heat the floor. Speed it up. All your btus won't be used up close to the manifold. You may be sending out 130 and bringing You may be carrying 110 degrees back to the boiler, not double digit lows you had when the flow was too fast. If I am not mistaken, Mr Holohan himself enlightened me on that. Didn't make sense but they he used a story about kids on a bus are like btus in a pipe. they travel too fast, they cant get off the bus so the delta T gets narrower.

This issue of Idronics may help clear up how heat transfer works , in any heat emitter.
An example of fin tube, at 1, 4 and 8 gpm. Notice the temperature increase in the fins. So higher output at higher flow..

And the hydronic formula to do the calculations if you have flow and delta T numbers.
https://www.caleffi.com/sites/default/files/media/external-file/Idronics_23_NA_Heat transfer in hydronic systems.pdf