Single heating loop using plastic tubing

Ted Robinson

I looked at a new construction building, 3 story with a separate apt on each floor. Each unit has a separate small gravity vented gas boiler with what seems to be a sngle loop of baseboards using the red plastic piping (1/2 inch). Each floor is about 1000 sq ft and I am concerned that there will not be enough water flow for a NY City winter design day. The system was not turned ON yet, so I cannot judge the performance. Does this sound like a working design?

Weezbo

why not?

Ted Robinson

Plastic pipe size

My concern is the volume of water that will squeeze through the saml id.

Ted Robinson

spelling oops

I mean "small id."

Richard_4

small id

How many feet of baseboard?

Tony_8

It depends

What's the heatloss ? How many feet of bbd ?

15-20,000 BTUH through 1/2" is normal. You can get more with sacrificing noise level and pump costs (both purchase and operating)

I'd like to know what kind of "red plastic" you're talking about. PEX or CPVC ?

Weezbo

fair enough.

just say the single loop designe of base board was adequate to meet designe the small gas boiler capeable of modulation and the base board convectors slightly oversized and the control allows for constant circulation....i still dont see anything intrinsically wrong with the idea.i have no problem with the idea ...other than zoning is often desireable...

Mark Eatherton1

ANd..

if zoning IS desirable, which it usually is, you can resort to the EnerJee 3 way non electric thermostatic bypass valve tocreate that effect.

FYI, I ran the numbers on Siggys SUperDuper software, and using a 1542, 60' of bbd, and 150' of 1/2" PEX it would deliver 20K btuh no problem. I seriously doubt that your load (except for the top floor) will exceed that.

ME

Ted Robinson

Single loop heat

Thanks folks for the responses - they are very helpful. Next week I may have more concrete data to add when I revisit the location. The total length of the baseboard is critical. This is a "builder" installation so the controller is a simple ON/OFF with fixed boiler/circulator settings. It would be very informative to learn how much the operating costs could be lowered with a higher efficency modulating boiler. My clients would be interested.

jeff_51

you might think about

adding a tekmar with remote outside sensor or something similar to modulate you heating curve. Alot cheaper than replacing boiler. When you figure your true savings of efficency vs replacement cost, that isn't always the most cost effective. Lets face it, boilers don't run at there peak efficiencys unless under optimum conditions, so you may not see that 15% you are thinking about. Yes I know thats why we use modulating boilers, but in small applications like this one, the payback in actual dollars is not very big.