Hitachi RAS-H(V)RNME-AF Service Manual page 154

5 Control system
• Heater wait time
If Water set-point (Ttwo) ≤ Maximum Heat Pump Operation, Electric Heater will be only allowed to operate when more than
electrical heater waiting time (5-005) Wait Time has passed since Heat Pump was started.
When Water set-point (Ttwo) > Maximum Heat Pump Operation or when heater needs to operate in emergency mode,
Electric Heater may be operated regardless of Wait time.
1
Heat Demand by
Thermostat
0
1
Heater Demand
[5-006 ]
0
1
Heater Output
0
User Variable:
CODE REF
5-005 WTEH Wait time for electric Heater
Heater inter-stage steps control
After each step increase, further step increases are prohibited during ISWT to avoid hunting. Step decrease does not have
this limitation. Since sampling time is 1 minute, at least 1 minute needs to pass between any step changes.
In any of the following conditions step will be forced to 0. This change will occur regardless of maximum 1-step change
and user defined delay:
1
Heater Demand
0
3
2
Heater Output
1
0
User variables:
CODE REF
5-004 ISWT Inter-Stage Wait time
144
SMGB0070 rev. 1 - 08/2011
5-005
Description Default Value
5-005 5-004
Description Default Value
Range
30 0~90
5-004 5-004 5-004
Range
5 0~10
Request
No request
Request
No request
ON
OFF
Time
Steps Units
1 min
No request
Request
Step 3
Step 2
Step 1
OFF
Steps Units
1 min