Routine Inspection & Maintenance Operations Community Heating System - Heatrae Sadia HI-MAX INSTANT ID 5-60 Installation, Operation And Maintenance Manual


Where gasket seals have had to be broken to
replace components,
clean and gaskets are undamaged. If in doubt fi t a
new gasket. See spares list on page 51.
9.3 Routine inspection & maintenance
operations - community heating system
9.3.1 Isolation
There are two isolation valves located at the top of
the unit to isolate the components in the unit from the
community heating system and a drain valve at the
bottom to drain any water contained within the unit.
9.3.2 Community heating fl ow verifi cation

There are two ways of verifying the fl ow through
the unit:
1) Confi rm the minimum pressure drop across the unit
using a manometer and taking measurements using
the P/T test points at the top of the unit. To do this
remove the actuator off the PICV, this will open the
PICV to the set design fl ow rate of the valve. Note the
valve should be set to 3 on models 5-60 and 4 on 5-80
models on the dial see Figure 55. Note that the Heatrae
Sadia HI-MAX INSTANT uses pressure independent
fl ow control technology, which means that as long as
the minimum pressure drop across the unit is achieved
at the design fl ow rate the correct fl ow rate should be
achieved. See Figure 56 below for details of the P/T
test points (Binder points not supplied) and Table 5 for
unit minimum pressure drops.
Figure 55: PICV setting
PICV Factory Settings:
5-60 = 3
5-80 = 4
Figure 56: P/T Test points
38
ensure sealing surfaces are
Table 5 Minimum primary system pressure drop at
maximum primary fl ow rate
HIU Model
ID 5-60
ID 5-80
* excludes heat meter
2) The heat meter should have the facility to interrogate
the actual fl ow rate through the unit. Again this should
be done with the actuator removed.

Important. Check that the PICV actuator pin is
in its fully retracted position before fitting. This means
driving the actuator to fully open the PICV. To do this
follow the procedure below:
9.3.3 Procedure to retract pin in the PICV actuator:
1) When the actuator is removed from the PICV, close the
district flow isolation valve.
2) Ensure there is power to the HIU.
3) Open a hot bath tap. The PID controller will attempt
reach the DHW set point by trying to open the PICV
(ie retracting the pin in the actuator).
4) Wait for 45 seconds to allow the actuator to travel its full
distance.
5) Switch the power to the unit off. The actuator pin will
remain in its fully retracted position.
The actuator is ready to fit on to the PICV. Carefully screw
the actuator back on by hand. DO NOT USE PIPE GRIPS.

Tighten the actuator collar by hand only. Do not
use a tool such as pipe grips or a wrench.
9.3.4 Check strainer for blockages

With the unit isolated at the valves on top of the
fi rst fi x rail, drain down the district heating side of
the HIU into a bucket using the drain valve located
underneath the fl ow hydroblock.

Unscrew the strainer service cap (see Figure 57)
and remove the mesh fi lter. Check for debris and
clean as necessary.

Replace fi lter and cap.
Figure 57: Community heating system strainer
9.3.5 Check Wiring

Turn off the electrical supply and remove casings.

Check that all terminals are still tight and haven't
become loose.
Minimum ΔP across unit
61 kPa *
78 kPa *
Service cap