converted gravity HW

STEAM DOCTOR

Good evening. I have a customer who just moved into a home with what I believe is a converted gravity hot water system. The mains are all 2" and the radiator runouts are 1 1/4 or 1". There is one radiator that is heating slower then the rest and one radiator that is not heating at all. Both have been blead. There is a single 007 circulator for the entire house. Those 2 rads are both being feed and returned from a common 1" T. There are other 1" lines in home that are heating without problem. The rad that is not getting hot is 3/4" baseboard(converted at some point from 1" rad).I am wondering if there is no flow to the 3/4" because of smaller size and as a result the 1" rad on that same T is being affected. Is there any benefit to replacing the 007 with a 3 piece circulator? I seem to remember from one of dans books that 007's dont belong on gravity systems. All thoughts would be appreciated. BTW the homeowner wants me to snake out the lines

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Zman

Snake it

After you snake the lines, I would be suspicious of the baseboard conversion. How is it piped? The oldtimers were pretty careful, the convertors, maybe not so.

Check out this on circ sizing http://www.heatinghelp.com/article/343/Circulators/238/Sizing-Circulators-for-Hot-Water-Heating-Systems

Carl

STEAM DOCTOR

thanks for the link

No way in the world that I am snaking it. would need to drain system, cut into steel pipe with no unions available, snake 1" line, reassemble somehow, hope not to crack the hundred year old lines and then after all of that we will be back to square one because there is no way in the world that the line is clogged. This is a closed system. Without air there is no rust. This is a flow issue no matter what the the home owner thinks

John S_2

baseboard

I'm with Zman, most baseboard is meant to be piped in series while rads are mostly in parallel. Had a job years ago where we had to add a separate circulator to feed the added baseboard zone. HO had the same kind of problem. Some earlier contractor had added baseboard to a rad system. Never heated up until we repiped as a separate zone.

TonyS

Two pipe direct return

That is the type of system that was used for gravity. As you follow out your supply main you will see the first radiator to get water is also the first back to the boiler. Water is lazy ,similar to electric and will take the path of least resistance. To make things more troublesome... someone added some baseboard.

The two best options are this.

1. Convert your two pipe direct return to a two pipe reverse return, if all the mains are visible and not under some god forsaken crawl space, this works out very well, setting up a natural balance in the system.

2. Install TRV,s on each radiator, this will shut off each radiator as the room comes up to temperature and redirect the flow elsewhere in the system. The TRV,s will also let you zone each room so in some cases there may be other savings as well.

Paul48

Bet

I'd bet it's air. I know you said it's been bled,but I've dealt with the same thing.