balancing diverter valves ,loops, and PDB valves

Bob Bona_4

Scott. And thank you for the input..make sense. What the baseline for start up was was purely intuitive. Future plans may include some basement finishing (radiant overpour, and a bumpout in the back of the house (radiant or panels). Want to have the main piping large enough to tap into.

I know the CI/SS/FP looks mismatched..hybrid..but, oh well. The whole shooting match would have looked nicer if the spray insulator hadn't gotten his overspray all over. Bending FP has it's places..and those places are tough to pick for us particularly minded folks :). Plus, I refuse to pay the sinful cost of copper!

Bob Bona_4

balancing panel rads/loops/PDB

See pictures at "Solo 110 install".

Now that project is done, I am looking for opinions/advice on the proper way to dial in flow rates on this system. Seat of the pants and common sense goes a long way, but would like to hear from others. This is the set up:

Solo 110 driving 8 panel rads w/ diverter valves. Constant circ, TRV's on rads. 1/2" PAP to rads. S/R lengths range from 5 feet to/5 feet from rads, to 30 ish feet to/from. Watts SS manifolds w/ flow meters and a cool pressure differential bypass that bolts on the end of the manifolds.

Questions: Where does one begin to balance? The PDB should be set for minimum boiler flow rate, correct? Once that is set, now which comes next- trying to even out the flow rates on the loops via the flow meters, or messing w/ the diverter bypass settings?

As is, the system is working pretty good with the diverter bypasses 1/2 open on the closer rads and the further rads have the bypass just about closed. I am attempting to balance flow at the manifolds to about 1/2 GPM via the flowmeters-which is easy for the close rads, but the far rads have to run wide open. Again, the system is working pretty well, by using some logic, and adjusting the TRV's.

What say you guys? TIA!

scott markle_2

I have used balancing manifolds for home run radiator jobs, but now question the economy or necessity, especially if trv's are used. When trv's are used the system becomes essentially self balancing. If a radiators is especially close to the manifold and another is quite distant there is a flow setter built into most panel rads that can be used to restrict the close ones. While the meters would certainly make this easer I have yet to encounter a situation were anything but a bit of intuitive tweaking was required. As far as the bypass valve my approach has been to leave enough radiators wild so as to eliminate the need. Save the trv's for bedrooms, guest rooms and perhaps mix trv's and non-trv rads in living areas, baths and entry ways wild. This approach depends on a careful calibration of the reset curve and ideally a user interface that allows for simple shifting of this curve based on user preferences.

I'm not to keen on trv systems that don't provide any user global adjustment of circulating temps other than ODR, It's a nice feature to incorporate timer setback into the odr curve, for those who prefer to sleep in colder temperatures. Although this does pose some issues with recovery unless indoor feedback is incorporated, Which of course must be monitored in a non-trv'd area.

The fosta looks good but why be so slavish to the straight and level approach of hard pipe. It seems like you could almost have eliminated enough fittings to use 3/4'' and had an equivalent head loss. For me the black iron and the fancy stainless manifold just don't look right in such close proximity.