HTP EL-399 - Manual (Page 18)

18
LP- 293 REV. 5.20.14
EXPANSION TANK SIZING
EL-80 1.4 Gallons
EL-110 1.7 Gallons
EL-150 2.0 Gallons
EL-220 2.6 Gallons
EL-299 / EL-301 3.1 Gallons
EL-399 3.7 Gallons
Table 2
Undersized expansion tanks cause system water to be lost from the relief valve, causing make-up water to be added. Eventual boiler
failure can result due to excessive make-up water addition. SUCH FAILURE IS NOT COVERED BY WARRANTY.
2. The expansion tank must be located as shown in Part 4, Boiler Piping, or following recognized design methods. See expansion tank
manufacturer’s instructions for details.
3. Connect the expansion tank to the air separator only if the air separator is on the suction side of the circulator. Always install the
system fill connection at the same point as the expansion tank connection to the system.
4. Most chilled water systems are piped using a closed type expansion tank.
DO NOT install automatic air vents on closed type expansion tank systems. Air must remain in the system and return to the tank to
provide an air cushion. An automatic air vent would cause air to leave the system, resulting in improper operation of the expansion tank.
DIAPHRAGM (OR BLADDER) EXPANSION TANK
Always install an automatic air vent on top of the air separator to remove residual air from the system.
E. CIRCULATORS
DO NOT use the boiler circulator in any location other than the ones shown in this manual. The boiler circulator location is selected to
ensure adequate flow through the boiler. Failure to comply with this caution could result in unreliable performance and nuisance
shutdowns from insufficient flow.
Sizing Space Heat System Piping
1. See Piping Details in this manual, Section G. In all diagrams, the space heating system is isolated from the boiler loop by the
primary/secondary connection.
2. Size the piping and components in the space heating system using recognized design methods.
F. HYDRONIC PIPING WITH CIRCULATORS, ZONE VALVES, AND MULTIPLE BOILERS
This boiler is designed to function in a closed loop hydronic system. We have included a temperature and pressure gauge that allows
the user to monitor the system pressure and outlet temperature from the boiler. It is important to note that the boiler has a minimal
amount of pressure drop that must be calculated when sizing the circulators. Unless the system has a closed type expansion tank, each
boiler installation must have an air elimination device that will remove air from the system.
Install the boiler so the gas ignition system components are protected from water (dripping, spraying, etc.) Allow clearance for basic
service of boiler circulator, valves and other components.
Observe the minimum
1” clearance around all uninsulated hot water pipes when openings around pipes are not protected by non-
combustible materials.
On a boiler installed above radiation level, some states and local codes require a low water cut off device, which is an optional part
available through HTP (Part # 7450P-225). Check with local codes for additional requirements. If the boiler supplies hot water to
heating coils in air handler units, flow control valves or other devices must be installed to prevent gravity circulation of boiler water in the
coils during the cooling cycle.
Chilled water medium must be piped in parallel with the boiler. Freeze protection for new or existing systems must use glycol that is
specifically formulated for this purpose. Antifreeze must include inhibitors that will prevent the glycol from attacking the metallic system
components. Make certain that the system fluid is checked for the correct glycol concentration and inhibitor level. The system should be
tested at least once a year and as recommended by the producer of the glycol solution. Allowance should be made for the expansion of