SylvanLMP
Hey Harold, I love hot water heating as it is not only very forgiving but you can play all sorts of great games with it.
Indoor out door set backs, non electric zone valves with and without remote bulb applications, the sizing is not that critical as compared to steam systems.
You can make a system as simple as a one pipe loop Or as complicated as a circulator for each zone with all kinds of by passes
The flow control valve I was talking about would require minimum HP to open as it would only be closed to the normal stratification of hot to cold movement.
The Solco and B&G types for example do not require much in the way of power to lift the weight up YET in time of circulator you can manually set them to open for gravitational flowing.
The problem with using a circulator supplied by a boiler manufacturer is Price. The manufacturers main concern is bottom line and “AVERAGE” demand
For example an automatic feeder is factory set 12-15 PSI so this would handle buildings up to 34.65 feet high above the boiler BUT in reality you must take off the positive pressure required to make sure air is not in the system “positive” pressure of 4 PSI which is I am correct would be almost 9 1/4 feet Then you have the friction losses to take into consideration and other restrictions.
I personally like B&G and am now trying Armstrong as per supply house recommendations SAME Price but a better warrantee IM told.
By using a circulator on constant run with the non electric thermostatically controlled valves the system would have a constant thermo setting with little coefficient of expansion per inch per degree taking place THUS no creeping sounds and less possibility of thermo shock
The supply and return (DELTA) temperature would indicate the exact BTU demand in velocity of this system once it was balanced out.
Another strong point about these older systems is the temperature of the heated water could be raised much higher with the same velocity with little concern as the newer copper systems should never be run at any temperature above 180 degrees with more then 2-3 FPS
1. Water at high velocity. High water velocity may be caused by an
undersized piping system or an oversized pump. One of the interesting myths
here is the notion that a return line failed because Type M copper was used,
so the repair is to install Type L copper. Since Type L copper has a smaller
ID than Type M copper, the velocity in the system is actually increased,
raising both the likelihood and rate of erosion that may take place. The
real solution is to lower the water velocity. Installation of a smaller
capacity pump or a throttling bypass on the existing pump should help in
lowering the velocity of the water in the system. The relationship is as
follows: Reduce pipe size, increase velocity; increase pipe size, reduce
velocity. Recommended velocity for hot water in a copper tube system is 4 –
5 feet per second (fps). If systems are designed to respect these velocities
the return lines will last as long as the rest of the system. The practice
of reducing tube diameter for the return line run is counterproductive and
is the main cause of high velocity in these systems. Since there is no
sizing guide in the Model Codes for return lines, there is little guidance
for the plumber on how to size this portion of the system. In the course of
installing or replacing circulating lines, some contractors have been
increasing the size of the return loop piping to 1″ or at least the same
diameter as the hot water supply out of the water heater.
2. Numerous, abrupt changes in direction in the piping system. Where
structural conditions cause numerous directional changes, long radius (1.5
Diameter) fittings should be used to minimize the interruption of laminar
flow. ( Hazen Williams) Pump manufacturers also have recommendations that limit the number of
changes in direction near the pump and the minimum distances these can be
installed from the pump. This is to protect the pump from these same
erosion/corrosion processes (cavitation). This is the main reason why you
would not use a corrugated connector on these pump installations. Flow
characteristics, the number and severity of the bends that could be made in
these connectors may be detrimental to the pump. < explains PUMP Burn out HUH?
Ah the joys of knowing ones job
Harold isn’t it fun talking professionally? LOL
