Radiator (hot water system) pipes need angle?

Jim Karr

We have a house built in the 20's with a hot water radiator system. I am currently working on remodeling the basement and we previously had a drop ceiling system, which is now being replaced with drywall. Problem is 2 pipes to the radiator in our dining room run 12' in and drop below the joists roughly 2" where they connect back to the main supply and return lines. Since the lines start at the very top of the joist on the radiator side, I could, after bleeding the system, raise the lines up so they no longer protrude past the joist, I'm just wondering if this will have any impact on the system performance??

Right now it's a 7" drop over 12', which if I calculate right is a 5% slope down to the return and supply. If I reduced that slope to 2.7% (possibly a little less, like 3.2% since I see a fitting is very rusted on the radiator side) is there going to be a problem with the system?

Thank You.

bob young

SLOPE

SINCE ITS A FLOODED , PUMPED SYSTEM , PITCH IS NOT CRITICAL AFTER INITIAL AIR REMOVAL [ BLEEDING & PURGING ]

Unknown

Is it still gravity?

Bob is right, however I saw no mention from you to a pump.
Assuming it is (gravity), you may have probs unless the system is properly cleaned.

Dave

Jim Karr

pumped..

Don't think there is a pump. New boiler installed about 5/6 years ago, but don't know if there is a pump inside. I just looked at it, it's a Dunkirk, with 3 lights on the front. One is "Call for heat circulator pump", "Gas Burner Valve" and "Main Power"

So would I be right to assume it's a pumped system with the circulator pump mention on the boiler?

Unknown

Thanks Jim

after hearing that,, I would concur with Bob.
Out of curiosity, what model Dunkirk is it?

Dave

Jim Karr

Dunkirk PWX-5ENG2

On the lower end of the boilers I believe looking at the efficiency, but, it's much better than the 80 year old boiler that was in here before and half if not more the size of the old one.

We've been happy with it, even if it is rated like 81 on the energy efficiency scale. No problems with it yet and I'm thinking it is a bit older than 5 or 6 years.

Jim Karr

Follow-up, rusted pipe question

When replacing the pipes that are rusted, should I use plumbers putty or is teflon just fine? And am I assume it's correct to use black pipe not galvanized as I've seen what happens to the inside of galvanized after 40 years.

Thanks All, this has been a very good experience. I appreciate the help!