LAARS HP-M2 Series - Installation, Operation and Maintenance Instructions - Manual (Page 12)

Page 12 LAARS Heating Systems
4B. Domestic Water Piping
Connect hot water tempering valve (12) “HOT”
port to hot water outlet from unit. This valve should be
mounted 3" to 6" below the outlet and set for 120° F
mixed delivery temperature or as local codes dictate.
H SERIES RECOMMENDS ANTI SCALD VALVE
SUCH AS SPARCO OR DANFOSS. (see Figure 13).
Connect gate or shutoff valve (13) to tempering
valve (12) “MIX” port, and cold water inlet.
Install supplied flow restrictor (14) ahead of mix
valve tee.
Connect pressure relief valve (1) (if required by
codes), maximum 150 PSI as close to the unit as
possible. No other valves or restrictions may be
installed between the H Series and the relief valve.
(DO NOT USE A TEMPERATURE/
PRESSURE RELIEF VALVE AS THIS IS NOT A
STORAGE HOT WATER HEATER).
*Model 60 is not recommended for larger hot
water demands.
WARNING
Failure to install a hot water tempering valve (12)
creates a scalding hazard with potential for serious
bodily injury. Some brands of tempering valves are
not designed as anti scold valves.
Installations with water containing 10 grains of
hardness or higher, must be installed with appropriate
water treatment.
SECTION 5.
Hydronic Heat Piping
5A. Hydronic Heat Piping
Hydronic Connections, Fittings and Accessories
(see Figure 16).
NOTE: A SEPARATE HEATING
CIRCULATOR MUST BE PROVIDED IN
SYSTEM PIPING, FOR ALL MODELS.
Connect system supply to 1" supply connection (A).
1.
Install thermostatic union (supplied) on H, HP
boilers.
2. Pipe the discharge of the relief valve, full size, to
a drain or in a manner to prevent injury or
property damage in the event of pressure relief.
3. Install an air purger (2) in supply line.
4. Install automatic float type air vent (3) on air
purger.
5. Connect diaphragm type expansion tank (5) to
air purger.
6. Install a boiler drain valve (8) adjacent to unit in
return line.
7. Connect system return to 1" return connection (B).
8. Install a properly sized circulator (9) with
optional isolation valves (10).
Caution
All hot water pipes must be installed with a
minimum 1" clearance from combustible materials.
NOTE: H, HP boilers installed in radiant (in
floor) systems and other low mass systems should be
provided with a buffer tank to assure constant supply
temperature without excessive boiler short cycling
(see Figure 17).
5B. Feed Water Make-Up
Connect boiler feed water supply with shut off
valve to inlet connection of automatic fill valve (4).
If codes require, install suitable back-flow
preventor (11) between automatic fill valve and city
main.
To ensure sufficient expansion volume of the
hydronic system water due to heat-up and cool-down
during normal operation, a #30 or larger expansion
tank must be used on all HW series applications.
H
E
A
T
M
A
K
E
R
12
1
13
13
14
15
CIRCULATOR
OPTIONAL RETURN LINE PIPING
AQUA-
STAT
WATER
SOFTENER
SUPPLIED
6"*
* or per valve manufacturers instructions.
Figure 13. Domestic Water Piping.
OUT OF
PRODUCTION