Walter Wilson HYDRA Series, Installation Instructions And Homeowner'S Manual

6. 

The flow of water through the system must be sufficient 
to continuously discharge the energy generated by the 
boiler.  If not, the High Limit protector will disconnect all 
the electric elements and a more or less frequent 
cycling mode will be established by the Safety Control 
(see the Technical Specifications Table, p. 10); 

7. 

In order to ensure satisfactory water flow, the friction in 
the piping system must not exceed the capacity of the 
circulator; 

8. 

After having completed all piping connections, run water 
through the system and purge the air.  The automatic 
vent should be in operation. 

Note:  Remove the panel on the right side of the unit and 
check to see if the elements and the temperature sensor are 
watertight. 

1.9) 

ELECTRIC POWER SUPPLY 

WARNING 

Risk of fire. 

The conductor sizing must conform to the last 
edition of the local or national codes. 

Failure to follow this rule can result in death, 
bodily injury and/or property damage. 

All electrical wiring must conform to the standards and 
regulations in force and the Canadian Electrical Code CSA 
C22.1. 
 
Electrical power to the boiler must come from a 120/240V 60 
Hz, single phase, 3-wire, grounded circuit, protected by an 
appropriately sized breaker, based on the total rating of the 
boiler.  Refer to the boiler nameplate and the technical 
specifications in this manual, p. 10, to select the proper 
breaker and determine the wire size. 
 
Power supply to the unit can be made using copper or 
aluminum wires.  The wire size must be decided in 
accordance to unit power consumption, the over current 
protection type and capacity, the wire type and length, and 
the environment where the unit is installed.  If an aluminum 
wire is used, other precautions (such as the use of a DE-OX 
inhibitor) must be taken to insure the conformity of the 
installation.  In all cases, all the factors affecting the wire 
gauge must be considered and the installation codes 
followed. 
 
The exterior of the unit must have an uninterrupted ground to 
minimize the risk of bodily harm.  A ground terminal is 
supplied with the control box for that purpose. 
 
In the event that wires inside the unit require replacement, 
these must be as same type as originals. (Copper wiring 
only). 

1.9.1)  Connecting the circulating pump 

The electronic circuit is designed in such a way that the 
circulator functions based on demand by the thermostat, or if 
a high limit condition is detected.  Refer to Figure 4, page 12 
for the connecting of the circulating pump. 

1.9.2) Connecting 

the 

thermostat 

Single heating zone 

Connect the low voltage thermostat to W1 and R terminals 
located inside the control panel on the electronic board, as 
represented on Figure 5, p. 13. 

Multiple heating zones 

Connect the contacts of the motorized valves or pump 
controls to W1 and R terminals inside the control panel on 
the electronic board. 

The anticipator inside the thermostat must be adjusted 
according to the electrical load connected to the thermostat. 

1.9.3)  Thermostat heat anticipator adjustment (if 

required) 

Certain thermostats are equipped with a heat anticipator that 
must be adjusted according to the instructions supplied.  
This is to ensure that the heating mode is comfortable and 
economical. 

Generally speaking, on a single stage thermostat, a reading 
of the current must be taken with an ammeter as follows: 

1)  Move the anticipator to its highest setting, rendering 

it ineffective. 

2)  Remove the wire from the “W1” terminal and 

connect an ammeter between the terminal and the 
wire. 

3)  Call for heat by raising the set point on the 

thermostat and allow the boiler to run for 3 to 4 
minutes to reach its peak output. 

4)  Once the current has stabilized, a reading should 

be taken and the anticipator adjusted to that value.  
If longer heating cycles are desired, the anticipator 
can be set to a higher value 

1.9.4)  Connecting the outdoor sensor 

Mount the sensor on an outside wall, protected from direct 
sunlight, so that it will accurately measure the outside 
temperature.  Install 2 only #20 wires between the outdoor 
sensor and the terminals identified as S1 and S2 on the 
electronic board terminal. 

5