Can I use 3/4" baseboard?

sunwave

I bought a 90,000 BTU input , 66,000 output boiler, According to the sizing formula i found online, GPM for 66,000 btu should be 6.6 GPM, so 1" pipe is required. I just wounder if i could use 3/4" baseboard? any comment is appreciated.

EBEBRATT-Ed

3/4" in one loop would be undersized. 3/4 is good for 4-4.5 gpm. Can you split the loop? 1" supply off the boiler 1X3/4 X 3/4 tee feed two 3/4 loops. run through baseboard. Tie returns back togeather with another tee as above and run 1" return to boiler. Split the amount of baseboard on each loop evenly if you can. It would be best to install a balancing valve valve on each loop in the supply or return (doesn't matter) but keep them the same for each loop.

hot_rod

What's the heatload of the building? Do you need 66K at design.

If the baseboard is 500 but/ ft output, for example, you would need about 132 feet of BB.

If you could split that into two loops as Ed mentioned, you could be fine.

Ideally a room by room load calc, as the baseboards at the end of the loop may need to be sized longer to get the required output at the lower temperatures they will see.

There are some series baseboard sizer programs to help, once you have the loads figured out.

sunwave

EBEBRATT-Ed said:

3/4" in one loop would be undersized. 3/4 is good for 4-4.5 gpm. Can you split the loop? 1" supply off the boiler 1X3/4 X 3/4 tee feed two 3/4 loops. run through baseboard. Tie returns back togeather with another tee as above and run 1" return to boiler. Split the amount of baseboard on each loop evenly if you can. It would be best to install a balancing valve valve on each loop in the supply or return (doesn't matter) but keep them the same for each loop.

Thank you, Ed!
Actually I want to do 2 loop as well, because the area of 1st FL is about 1000 sq. ft, and i only intend to heat 600 sq. ft of the usable basement area. In this case, baseboard distribution for each loop might not be even, could balancing valve take care of this problem? Which balancing valve do you recommend?

sunwave

hot rod said:

What's the heatload of the building? Do you need 66K at design.

If the baseboard is 500 but/ ft output, for example, you would need about 132 feet of BB.

If you could split that into two loops as Ed mentioned, you could be fine.

Ideally a room by room load calc, as the baseboards at the end of the loop may need to be sized longer to get the required output at the lower temperatures they will see.

There are some series baseboard sizer programs to help, once you have the loads figured out.

Hi, Hot rod, I have 1000 sq ft 1st FL + 600sq ft basement to heat up. Do you think the system is over sized?
If I add 2 zone control to this system, does this have positive or negative effect? or none? Thank you!

icesailor

IMO.

Unless you plan on living in the basement, it is a waste of time and materials to put a basement on a separate heating zone or put heat in the basement. Unless you have some extremely extenuating circumstances, cellars with heating equipment just don't get that cold. I never saw a house with total electric heat and a heater in the cellar turned off, that ever had a freeze up. Nor in enclosed crawlspaces unless foundation vents were left open or were drafty and leaking air.

hot_rod

sunwave said:

hot rod said:

What's the heatload of the building? Do you need 66K at design.

If the baseboard is 500 but/ ft output, for example, you would need about 132 feet of BB.

If you could split that into two loops as Ed mentioned, you could be fine.

Ideally a room by room load calc, as the baseboards at the end of the loop may need to be sized longer to get the required output at the lower temperatures they will see.

There are some series baseboard sizer programs to help, once you have the loads figured out.

Hi, Hot rod, I have 1000 sq ft 1st FL + 600sq ft basement to heat up. Do you think the system is over sized?
If I add 2 zone control to this system, does this have positive or negative effect? or none? Thank you!

Sounds like a big boiler for 1600 sq. ft? 1600 X 25 btu/ ft is 40,000 btu/hr. 25 is just a guesstimate, but...

The only way to answer the question is to perform a heatload calc.

Look for the SlantFin Virtual Heat Loss Calculator app at www.slantfin.com Quick and easy.

You really don't want an oversized boiler

bmwpowere36m3

@sunwave

Did you do the heat loss calc yourself? For example my house, 1 story, built '56, 1600 sq ft (non-heated basement) I figure 37k BTUs. Granted I just redid the siding, insulation, air barrier, sealing, windows, doors, etc... and my design temp is 7*.

The less zones the better in terms of simplicity and cost. However you also lose the ability to regulate temps in different areas of the house. If you do a large series loop, then the baseboard sections at the end of the loop will need to be larger due to supply temp drop thru the loop. However you can avoid that by splitting the supplies and joining the returns together, like in parallel.

First you should consider "zoning", you're habits and desires as far as temperatures within the home. Examples would be: living areas at one temp, bedrooms slightly cooler and bathrooms slightly warmer (don't you hate getting out of the shower into a "cold" bathroom). Or maybe you have an infrequently used room that you'd like to keep the temps lower in.

sunwave

hot rod said:

sunwave said:

hot rod said:

What's the heatload of the building? Do you need 66K at design.

If the baseboard is 500 but/ ft output, for example, you would need about 132 feet of BB.

If you could split that into two loops as Ed mentioned, you could be fine.

Ideally a room by room load calc, as the baseboards at the end of the loop may need to be sized longer to get the required output at the lower temperatures they will see.

There are some series baseboard sizer programs to help, once you have the loads figured out.

Hi, Hot rod, I have 1000 sq ft 1st FL + 600sq ft basement to heat up. Do you think the system is over sized?
If I add 2 zone control to this system, does this have positive or negative effect? or none? Thank you!

Sounds like a big boiler for 1600 sq. ft? 1600 X 25 btu/ ft is 40,000 btu/hr. 25 is just a guesstimate, but...

The only way to answer the question is to perform a heatload calc.

Look for the SlantFin Virtual Heat Loss Calculator app at www.slantfin.com Quick and easy.

You really don't want an oversized boiler

Thank you! I've done the calculation, it gave me 60k btu, I guess old house does need more heat to make up the loss.
you were right, this unit is over sized.

sunwave

bmwpowere36m3 said:

@sunwave

Did you do the heat loss calc yourself? For example my house, 1 story, built '56, 1600 sq ft (non-heated basement) I figure 37k BTUs. Granted I just redid the siding, insulation, air barrier, sealing, windows, doors, etc... and my design temp is 7*.

The less zones the better in terms of simplicity and cost. However you also lose the ability to regulate temps in different areas of the house. If you do a large series loop, then the baseboard sections at the end of the loop will need to be larger due to supply temp drop thru the loop. However you can avoid that by splitting the supplies and joining the returns together, like in parallel.

First you should consider "zoning", you're habits and desires as far as temperatures within the home. Examples would be: living areas at one temp, bedrooms slightly cooler and bathrooms slightly warmer (don't you hate getting out of the shower into a "cold" bathroom). Or maybe you have an infrequently used room that you'd like to keep the temps lower in.

Thank you for the info. You are right, zoning is unnecessary sometimes.
I have a huge family, so the basement is used as living room and entertainment room. And I am thinking to develop the unused portion of the basement for guest bed room in the future. For now this unit is definitely over sized.

sunwave

icesailor said:

IMO.

Unless you plan on living in the basement, it is a waste of time and materials to put a basement on a separate heating zone or put heat in the basement. Unless you have some extremely extenuating circumstances, cellars with heating equipment just don't get that cold. I never saw a house with total electric heat and a heater in the cellar turned off, that ever had a freeze up. Nor in enclosed crawlspaces unless foundation vents were left open or were drafty and leaking air.

you are right, but my case is a little different. I placed all heating equipments in the locked utility room to keep kids away. And we use basement a lot since i have a big family.

icesailor

I hope you have adequate make up air in this locked up space to keep the little kids out. Little kids grow up.

I hope you don't create too many "issues" with a tight closet install.

sunwave

icesailor said:

I hope you have adequate make up air in this locked up space to keep the little kids out. Little kids grow up.

I hope you don't create too many "issues" with a tight closet install.

The utility room has a window, air should be adequate.

Hilly

You need proper make up air for combustion requirements. Unless you have a hole cut in the window it probably wouldn't cut it.

icesailor

Hilly said:

You need proper make up air for combustion requirements. Unless you have a hole cut in the window it probably wouldn't cut it.

Some I/O manuals have the specific requirements for combustion air in confined spaces. Few confined space applications meet the requirements.

hot_rod

What type of boiler? Many are sealed combustion now a days. It may not need combustion air via an opening. And the manual; will give clearances to combustibles.

sunwave

hot rod said:

What type of boiler? Many are sealed combustion now a days. It may not need combustion air via an opening. And the manual; will give clearances to combustibles.

Sentry Slantfin S-90

sunwave

from the manual:

minimum clearance for combustible construction：
front--6"
rear--6"
Left side--6"
Right side--12"
Top--12"
Flue connector--6"

hot_rod

The manual spells out combustion air requirements. Note also you may need a combustible base, if it is installed on a wood floor.

sunwave

hot rod said:

The manual spells out combustion air requirements. Note also you may need a combustible base, if it is installed on a wood floor.

Thank you for pointing out, I'll make sure all the requirements are met.
This unit will be sitting on the concrete floor of basement.

hot_rod

We want you to be comfortable, but also safe.