Adding GHW - 1943 home

Jim_141

I have a 1940's house w/gas forced air located in PA. It's a (5) multi-level, 1st is basement, then up to a den and .5 bath on 3' crawl, then up 7 steps LR/DR/kit w/full basement, up 7 steps (above the den & bath) is two Bdrms w/full bath and above the LR/DR is the master bdrm.

I found cast iron radiators and a 2 yo old Burnham boiler. 165k btu +/-. I purchased a Taco 6 zone control, copper 3/4 sweat fittings and full 3/4 sweat ball valves, plus the thermostat wire.

I plan on plumbing a copper supply and return loop in the basement with 4 zones w/4 pumps. Plumbing the LR/DR/Kit will basically be a strait drop into this loop from above- zone 1. In this basement I was going to install the ball valves at each rad supply to control the heat at each radiator- no valves at actual rad. Zone 2 Den/.5 Bath I wanted to run copper supply to the crawl area and change to PEX supply & return, same with the zone 3 above, change to PEX in the wall, making fishing easier. Plumbing to the master bdrm zone4 can easily be done in copper.

My concerns, Can I use just one return loop in basement to return multi-zone loops? I think it's ok. And is there any issue with changing a supply from copper to PEX and back to a copper return? All zones will have its own pump, costing more, but I think it's better system/design vs zone valves. Also, the master bdrm zone will only have one big radiator, Can you have one rad on 1 zone only? Running all the thermostat wires will be a challenge but possible. Does distance/length make a difference? and can I run the wire attached the copper return, ie. does heat effect the wire?

I consider myself very handy and I can sweat 1/2" w/o problems. People in the trade look at me like I'm building the Great Wall myself. The hardest part will be moving the radiators again, and making sure my design idea will work. Most will say have the system engineered, I think having each rad w/valve can reduct too much heat in the rooms.

Any insight in this project is appreciated.
Jim

jalcoplumb_7

Heat-Loss Calc.

You should start with the heat-loss calculation. Find out what each room requires and the total for the whole structure. Make sure the boiler is not over or undersized. When you know how much heat is required for each room, put the appropriate sized radiation in that room. Need help with the heat-loss calculation click on the link at the top of the page.

As for the zones figure out how many btu’s will be in each zone and make sure your supply and return piping is sized to handle the load. If the zones are small then the boiler might short cycle and use more gas/oil than it should.

I use pex a lot. I like to use a radiant manifold at the boiler and run the radiation back to it. One manifold per zone works. Might cost more but the manifolds I use have a flow control valves and a flow meter built in. Great for balancing the system.

Need to be careful with the pex that you don’t have to long of a run. Or you might not have enough flow.

Speaking of flow need to make sure your circulators are sized properly as well.

A lot of stuff to think about. The t-stat wire is the least of the worries.

Good Luck.