Install Instructions

IM-PR 566442 1114 (Design Manual)
132
Size (in.) O.D. (in.) I.D. (in.)
Water Content
(Gal/ft)
½ 0.625 0.475 0.009
⅝ 0.750 0.574 0.014
¾ 0.875 0.671 0.018
1 1.125 0.862 0.030
Table 5-22 ViegaPEX Barrier and FostaPEX tubing
specifications
A system uses 10,000 ft of ⅝" ViegaPEX Barrier
tubing and has 30 gallons of volume within the
boiler and additional tanks and reservoirs.
Water content: 10,000 x 0.014 + 30 = 170 gal
% glycol mixture selected is 40%
Glycol gallons required: 0.40 x 170 = 68 gal
Purging
Once the pressure test has been successfully
completed and the system is filled with glycol
solution, follow these steps to purge the system.
1. Remove the high-limit from any mixing valve.
The high-limit can be reinstalled and reset
after the purge is complete. For instructions
on setting the high-limit, see Section 4.2.3.
2. Close isolation ball valves on supply and
return headers.
3. Connect fill hose/purge kit to drain valve on
supply header.*
4. Attach a drain hose to the return header
drain valve.
5. Open drain valve on supply header to start
water flow into supply header.
6. Once purge and fill for first circuit is
complete, close circuit shutoff valves on
supply and return headers.
7. Repeat steps 4 and 5 for each additional
circuit, one at a time.
8. Once last circuit is purged and filled, close
last circuit shutoff valve.
9. Open all circuit shutoff valves on supply and
return headers.
10. Close drain valve.
NOTE: If the system must be purged again in
the future for any reason, the high-limit must be
reopened during purging for full flow.
*Use of a fill and purge kit is recommended for
snow melt systems. Building a fill and purge
kit will allow the fill and purge process to be
quick, efficient and easy. Figure 5-17 shows an
economical kit (parts supplied by others).
Figure 5-17 Example of a fill and purge kit
Kit consists of:
1) Barrel (~35 gal)
2) Double female hoses
3) Foot valve
4) Transfer pump
5) Pressure gauge
Return from System
Supply to
system
2
2
2
3
4
5
1
5.13.2 Initial Balancing
If the snow melt circuits are of different lengths,
the system should be balanced in order to provide
adequate flow to each circuit. Refer to your design
for detailed balancing flow rates. Procedure:
Balancing Circuits
It is important to balance the circuits on the
manifolds to ensure even distribution of the radiant
heating. The fluid (water and glycol mix) flows in
the path of least resistance. Longer circuit lengths
cause higher pressure drops (resistance). The
shutoff/balancing valves can equalize the pressure
drop (resistance) in every circuit. For proper
balancing see calculations and diagrams on the
following page.