User Guide
63
Design Guide - HZH/HZV Series
HZ Series 60Hz
Engineering Specications – Page 4
Refrigerant to air heat exchangers shall utilize enhanced corrugated lanced aluminum ns and ried copper tube or all
aluminum microchannel construction rated to withstand 625 PSIG (4309 kPa) refrigerant working pressure. Refrigerant to
water heat exchangers shall be of copper inner water tube and steel refrigerant outer tube design, rated to withstand 625
PSIG (4309 kPa) working refrigerant pressure and 500 PSIG (3445 kPa) working water pressure. The refrigerant to water
heat exchanger shall be “electro-coated” with a low cure cathodic epoxy material a minimum of 0.4 mils thick (0.4 – 1.5
mils range) on all surfaces. The black colored coating shall provide a minimum of 1000 hours salt spray protection per
ASTM B117-97 on all external steel and copper tubing. The material shall be formulated without the inclusion of any
heavy metals and shall exhibit a pencil hardness of 2H (ASTM D3363-92A), crosshatch adhesion of 4B-5B (ASTM D3359-
95), and impact resistance of 160 in-lbs (184 kg-cm) direct (ASTM D2794-93).
Refrigerant metering shall be accomplished by thermostatic expansion valve only. Expansion valves shall be dual port
balanced types with external equalizer for optimum refrigerant metering. Units shall be designed and tested for operating
ranges of entering water temperatures from 20° to 120°F (-6.7° to 48.9°C). Reversing valve shall be four-way solenoid
activated refrigerant valve, which shall default to heating mode should the solenoid fail to function. If the reversing valve
solenoid defaults to cooling mode, an additional low temperature thermostat must be provided to prevent over-cooling
an already cold room.
Option: The unit will be supplied with a cupro-nickel coaxial water to refrigerant heat exchanger.
Option: The unit shall be supplied with a hot water generator (desuperheater).
Drain Pan:
The drain pan shall be constructed of Stainless Steel to inhibit corrosion. This corrosion protection system shall meet
the stringent 1000 hour salt spray test per ASTM B117. If plastic type material is used, it must be HDPE (High Density
Polyethylene) to avoid thermal cycling shock stress failure over the lifetime of the unit. Drain pan shall be fully insulated.
Drain outlet shall be located at pan as to allow unobstructed drainage of condensate. Drain outlet for horizontal units
shall be connected from pan directly to MPT tting. No hidden internal tubing extensions from pan outlet extending to
unit casing (that can create drainage problems) will be accepted. The unit as standard will be supplied with solid-state
electronic condensate overow protection. Mechanical oat switches will NOT be accepted.
Vertical units shall be furnished with a PVC FPT condensate drain connection and an internal factory installed condensate
trap. If units without an internal trap are used, the contractor is responsible for any extra costs to eld install these
provisions, and/or the extra costs for his sub-contractor to install these provisions.
Electrical:
A control box shall be located within the unit compressor compartment and shall contain a 75VA transformer, 24 volt
activated, 2 or 3 pole compressor contactor, terminal block for thermostat wiring and solid-state controller for complete
unit operation. Reversing valve and fan motor wiring shall be routed through this electronic controller. Units shall be
name-plated for use with time delay fuses or HACR circuit breakers. Unit controls shall be 24 Volt and provide heating or
cooling as required by the remote thermostat/sensor.
Option: Units shall be supplied with factory installed non-fused electrical service disconnect switch.
Solid State Control System (DXM2):
Units shall have a solid-state control system. Units utilizing electro-mechanical control shall not be acceptable. The
control system microprocessor board shall be specically designed to protect against building electrical system noise
contamination, EMI, and RFI interference. The control system shall have the following features:
• Anti-short cycle time delay on compressor operation.