IDEAL INDUSTRIES HE12, HE24, HE18, HE15 manual General Open Vent System Requirements, Balancing

GENERAL

3 OPEN VENT SYSTEM REQUIREMENTS

The system should be vented directly off the boiler flow pipe, as close to the boiler as possible. The cold feed entry should be inverted and MUST be positioned between the pump and the vent, and not more than 150mm (6") away from the vent connection.

Note. Combined feed and vent pipes may also be fitted.

There should be a minimum height 450mm (18") of open vent above the cistern water level. If this is not possible refer to Frame 5. The vertical distance between the highest point of the system and the feed/expansion cistern water level MUST not be less than 450 mm (18"). The pump must be fitted on the flow side of the boiler.

A suitable pump is a domestic circulator capable of providing a maximum 11oC (20oF) temperature differential across the boiler with the whole of the heating circuit open (e.g. Grundfos UPS 15/50, 15/60 or equivalent). With the minimum flow circuit allowed by the controls the differential must not exceed 25 oC. (18oC for the HE15)

The vertical distance between the pump and feed/expansion cistern MUST comply with the pump manufacturer's minimum requirements, to avoid cavitation. Should these conditions not apply either lower the pump position or raise the cistern above the minimum requirement specified by Ideal Stelrad Group. The isolation valves should be fitted as close to the pump as possible.

Return & flow connections

load 30 - 60 = 22 mm load 70 - 80 = 28 mm

4 SCHEMATIC PIPEWORK AND SYSTEM BALANCING

The boiler does not normally need a bypass but at least some radiators on the heating circuit, of load at least 10% of the minimum boiler output, must be provided with twin lockshield valves so that this minimum heating load is always available (see footnote re. thermostatic radiator valves).

Balancing

1.Set the programmer to ON for both CH

and HW. Turn the cylinder thermostat down. Close the manual or thermostatic valves on all radiators, leaving the twin lockshield valves (on the radiators referred to above) in the open position. Turn up the room thermostat and adjust these lockshield valves to give boiler flow and return temperatures not more than

20 oC apart. These valves should now be left as set.

2.Open all manual or thermostatic radiator valves and adjust the lockshield valves on remaining radiators to give around

11oC temperature drop at each radiator.

3.Turn up the cylinder thermostat and

adjust the cylinder balancing valve so that the cylinder achieves a maximum flow consistent with adequate flow to the radiators. Check that with only the domestic hot water loop in circuit a differential temperature of 20 oC across the boiler is not exceeded.

4.Adjust room and cylinder thermostats and programmer to NORMAL settings.

10 icos - Installation & Servicing