Pumping Towards @ 1 1/4\"

ALH_4

What type of system is this? Is the circulator sized properly? It may be undersized. What is the heat loss? How many square feet is each zone? It is likely that larger header piping would be ideal, but it also might be that even with that larger header piping, you need more flow than your existing circulator can supply.

Another possibility is that the head loss in the zones may not be balanced enough so that the smaller zones steal most of the flow from the larger zone. It may be that you need balancing valves on the smaller zones, and you may be able to retain the header piping and the current circulator size with no problems.

If you do need to install a larger circulator, I strongly recommend also installing a differential bypass valve. Install a ball valve in the bypass to close the bypass while filling the system.

ChasMan

I need to replace my circulator pump. While I am at it, I was wondering if it would be worthwhile to make the outlet larger. I have four 3/4" zones fed by 3/4" copper that comes out of the pump. When we dropped a couple of degrees below design I couldn't hold the house at 68 degrees on the main zone and am wondering if that might help a bit?

Probably not because this is the return side where the pump is which I cant change now. On the supply side where the zone valves are, if I make that a 1" manifold and make the retun side a 1" mnifold would that be better?

Weezbo

sizing your manifold is important in the design of a heating

system ,guessing at it doesn't work real well. however if 3/16ths doesn't work 1/2' may work better ,although what you might actually need is 1 1/4" . what you want to consider is the amount of heat that you need to deliver .to make the case for the design of a system, with insufficient emitters changing pipe sizes and increasing circulator sizes wont produce any miracles.

what you are asking will likely require a shade more information...

ChasMan

No doubt

Sizing it corectly would help I am sure. But with the house under renovation and expanding here and there its hard to be definitive on what the ultimate heat loss and radiation / zone layout will be. I take it making it bigger can only help. I know splitting one zone into two has made for much more heat available in that part of the house. However, the 3/4" supplying the 4 zones now appears to be starved when I put all 4 zones on. The primary zone temperature starts to drop as more zones call for heat. So as long as there is no harm in going bigger, I think I will.

hot_rod

How large is the heat source?

the pipe should be sized to the amount of flow needed to keep that happy.

1" would easily handle 8 GPM or 80,000 BTU at a 20 degree delta T. If your boiler is that size or smaller no need for 1-1/4" piping, as the purgers, valves fittings, etc just go up in price.

hot rod

ChasMan

Thanks

Thanks Hot Rod, The Heat loss of the house is about 72K but the boiler is 125K. I think 1" should be enough then. Dang, need a new reducer :-) The pump is a 007 Taco.

ChasMan

Thanks

The heatloss is apox 79K for the whole house. One Zone is 10K, another 10K, another 20K (2nd floor) and another 38K. The 38K zone (main one) has 65 feet of fin tube in it so from a radiation standpoint its kind of close. It seems to be mostly adequate but at design outdoor temp (7 degrees F) I can barely keep it at 68 degrees. However, the other smaller zones heat just fine when its that cold. Its fairly easy for me to put 1" pipe in there and thats what I think I will try to start with. I plan on replacing the boiler in a couple of years and at that time Ill rethink the whole darn thing. Hopefully we might get another design day to test the 1" pipe out with.

ALH_4

balancing

The 007 is pretty close. A 0010 might be what you need. If there are valves on the zones, you might try throttling back the smaller zones on a day when the main zone is not keeping up and see what happens. Taco also has a nice 3/4" dP bypass that wont break the bank. I have a feeling the large zone gets starved for flow when the smaller zones call.

ChasMan

Poor Mans Bypass

Excellent, I can try that when it gets cold again. For today, I have my aquastat at 135 / 165 with a 20 deg diff. You would never know there was an issue on a lovely day like today. Im going to swap the pump for one of those 3 speed jobs from Wilo, Its only a tich bigger than the 007 on high speed but I think most of the time I should be ok with speed 2. Ill swap the return manifold out for 1" pipe and later, I'll change the supply to 1". Then when I replace the boiler I hope there are some niftier pumps around. One thing I thought of was to put a relay network on the pump so it runs at speed one with certain valves open, speed 2 with others and speed three with all 4. Just an idea, dunno if its a good one.

Chris S

wrong sized piping

Hot Rod,

I bave a new customer in a commercial building that has a 230,000 btu boiler with a 1 " feed & a 1" return. The high limit is set at 210. I got called last week because the were complaining the radiant zone was cold. The radiant zone consists of 3/4" copper under the wooden floor in the office area. I tried to convince my customer that if it was installed properly they wouldn't even be able to walk on it ( 210 degrees !!). The plumber who installed all of this is a dead guy- yes I read Dan's book. Unfortunately this customer will only allow maintenance on the system, we won't get a chance to fix it. I'm writing this more as a vent than anything, I'm sure you've all seen worse.

We keep a simple chart for the installers showing what pipe size to use for the corresponding BTU load at 180 degrees. While we don't use 1/2" pipe- we do use a lot of 5/8 for heat loops & then on up to boiler header size. Trying to get them to think for themselves.

Chris

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Tony_23

Just wait : )

Wilo has a residential circ coming out called the "Eco", it will do all that and at a minute cost of electricity.

hot_rod

How can 210F copper not

heat a wood floor? Something seem amiss.

I have actually seen more then one 180f boiler to copper slab job around here. A bunch were installed in the 50's sometime. Oddly enough the owners loved them. Some have original cast iron boilers still attached!

I remember one where the vinyl floor tile would squirm around as you walked across, the concrete was that hot.

hot rod

Chris S

210 degree

The installation is a framed raised (20") platform over a concrete slab. It is inaccessible. I think that they framed it , installed all of the copper down at the bottom of the floor joists- no insulation , heat plates, foil - nothing. I think the place where the mice are living is warm- but there is enough draft & heat loss to the the concrete etc. that it's not really doing its intended job. I've seen similar installation id residential construction that worked well- 2 nd floor framing no drafts SR on the bottom flooring on top- sealed ends. Not the case here.
I thought you'd comment more on the 1" piping with that BTU output
Chris

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"