MCDonald Powerflow Instructions Manual

UNVENTED HOT WATER SYSTEM

QUEENSWAY INDUSTRIAL ESTATE,
GLENROTHES FIFE KY7 5QF
Tel : [phone] Fax : [phone]
Email : [e-mail]
Internet : www.mcdonaldwaterstorage.com

FOR SPARES CALL 01592 611123

INSTRUCTIONS

PLEASE LEAVE WITH HOUSEHOLDER

IMPORTANT - Failure to install and maintain this system

in accordance with these instructions will invalidate the
manufacturer’s warranty. Extended warranty card to be

completed and returned.

ANNUAL SERVICE REQUIRED

1

FOR SPARES VISIT WWW.MCDONALDWATERSTORAGE.COM OR CALL 01592 611123

IMPORTANT

Installation should only be carried out by a
‘competent operative’ i.e. the installer must
have attended a recognised course in
Unvented Hot Water Systems or received
appropriate training in their apprenticeship.
All registered operatives should carry an
Identification Card issued by their
certificate provider – for example BPEC or
SNIPEF. Installation should be carried out
in accordance with current local Building
Regulations and water Byelaws.

The unit should be handled
with care in order to avoid damage to
valves. It should be stored upright in a dry
place.

Full weights are available on page 7 of
this booklet. The installation area should
be able to cope with this weight, incoming
pipes and discharge pipe. Position the
unit to suit the installation.

Generally connections are to the front to
enable ease of access. Alternatively if a
sketch is provided refer to that. Ensure
suitable space is left for access for repair
and/or replacement of valves etc.

In areas with hard water we would
recommend restricting the temperature
and performing de-scaling procedures as
required.

All the following instructions must be
carried out: -

1. Installers should ensure incoming
mains pressure is less than 12Bar and
that local authority approval for
installation of Unvented Systems is
granted. Ensure adequate flow-rate is
available.

2. Excessive use of flux

can damage the
unit and especially the valves and
expansion vessel. Avoid over-use and

ensure the system is fully flushed of
any debris or flux before connection.

3. Incoming mains to arrive in a
minimum of 22mm copper pipe. Fit to
the Pressure Reducing Valve A

(See
Page 4) set at 2.1 Bar. Contract
Models 1.5 Bar and 3 Bar Models – 3
Bar. This includes a serviceable
Strainer. We would strongly
recommend this valve is fitted where
the mains enters the property, but it
can go wherever is most suitable for
the installation, between the mains
stopcock and the cylinder.

We recommend fitting a Tee between

the Pressure Reducing Valve (A) and
the Check Valve (A2) to provide a
BALANCED COLD OUTLET for all
cold taps, preventing cross-flow and

also giving potable water throughout
the house. Outdoor taps for hoses

should be taken before the Pressure
Reducing Valve.

4. The Check Valve

(A2) is supplied
loose, to be fitted between the
Pressure Reducing Valve and before
the Expansion Vessel on the Cold
Feed. Any balanced cold draw off
should be fitted between the Pressure
Reducing Valve (A) and the Check
Valve (A2).

5. The Temperature & Pressure Relief
Valve (D) set at 90°C and 4.5 Bar (3
Bar models set at 7 Bar), and the
Expansion Relief Valve (B) set at 3.5
Bar (Contract Model 3 Bar and 3Bar
Models 5 Bar), should be fitted and
connected to the Tundish (E). NB -
the relief valves are only to be used
for relief discharge purposes.

No valves should be fitted between

the relief valves and the cylinder.

2

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6. The Tundish (E), which shows visible

discharge from the Relief Valves, is to
be in a prominent, visible and safe
position away from any electrical
devices (likewise with the drain
connection) and within 500mm of the

Temperature & Pressure Relief Valve

(D). Pipework from the Tundish (E)
must initially be vertical for a minimum
of 300mm where possible and then
have a continuous fall in excess of 1
in 200. Pipework away from the
Tundish (E) should be in a minimum of
22mm, of material suitable for
temperatures of 95°C and have a
resistance to flow of water not greater
than that of a straight pipe of 9 metres
(each bend or elbow is equal to 0.8
metre of resistance). See BBA
Information. Sheet No 33:1989 for
further details - available from the
manufacturer. Also note page 9 of
these instructions.

7. The Expansion Vessel

(F) should be
set the same as the Pressure
Reducing Valve (A) - 2.1Bar (Contract
Models 1.5Bar and 3Bar Models 3Bar).

The Expansion Vessel should be fitted

to the wall and connected to the Tee
(F1), between the Check Valve (A2)
and Cold Feed, (hard piped or fitted
with the braided flexi-hose). (On
previous units the check valve was
factory fitted to the Cold Feed). No
isolating valve is allowed between the
Vessel and the Cold Feed.

The Vessel must also be fitted within

2m of the cylinder.

8. Connect the 3kW 11” 240V Immersion
Heater/s BSEN 60335/2/73 (with
manual re-set cut out at 80°C) to the
power supply and earth them in
accordance with the current IEE wiring
regulations. The fuse rating should be
13 Amps. Do not at any time fit

Immersion Heaters without a thermal
cut-out.

9. On Indirect Units

where a Coil is fitted

to the cylinder, when supplied, the

Two Port Motorised Zone Valve

and

Dual Thermostat Controller

(J) must
be fitted in accordance with the
instruction details supplied with them
for the appropriate installation. See
back page for Solar & Heatpump
coils

N.B. Indirects, are suitable for oil,

gas and electric fired boilers on a
pumped, gravity or sealed system.
(We would however recommend
28mm Coil connections with a 28mm
Zone Valve on gravity systems).
Maximum working pressure of the
coil is 3.5 Bar. All electrical wiring to

thermostats, zone valve and
immersion heaters must be earthed
and to current IEE Wiring Regulations.
The fuse should generally be 3 Amps
but refer to appliance instructions to
confirm this.

10. The Secondary Return

(L) if supplied,
should be plugged if not required. If
the Secondary System pipe-work is
greater than 15% of the unit capacity,
a larger Expansion Vessel may need
to be fitted - contact McDonald Water
Storage.

11. Immersion Heaters

(H) and the Dual

Thermostat Controller (J) supplied
with the Indirect units should be set to
no greater than 60°C and the internal
High Limit Thermostats are factory set
no higher than 85°C. Always check

this before switching on power.

(Immersion Heaters - 1 = 10ºC, 2 =
25ºC, 3 = 40ºC, 4 = 55ºC, 5 = 70ºC).

Please see the checklist on page 4 to

ensure all controls are present and
correct.

3

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ONCE ALL THE PRECEDING INSTRUCTIONS HAVE BEEN
FOLLOWED, COMMISSION THE SYSTEM.

IMPORTANT

COMMISSIONING - These instructions
must be followed.

After following the instructions on pages
1 & 2 proceed as follows: -

1. Close the Drain (I) at base of cylinder.

2. Open a Hot Tap.

3. Fully open the Cold Mains Stopcock
and fill Cylinder until water appears at
the Hot Tap.

4. Close the Hot Tap and attend each hot
water outlet in turn and ensure water
flow is obtained at each.

IT IS THE RESPONSIBILITY OF THE
INSTALLATION ENGINEER TO CHECK
AND ENSURE THAT ALL VALVES,
FITTINGS AND IMMERSION/S ARE
PROPERLY SEALED AND WATERTIGHT.

5. Check the control thermostats on the

Immersion Heater/s (H) and the Dual
Thermostat (J) are set no higher than

60°C and that the High Limit
Thermostats are set to no higher than
85°C.

6. Ensure there is no discharge from the
Relief Valves (B and D).

7. Switch on water heating system and
check operation of the system.

IT IS EXTREMELY IMPORTANT TO
FOLLOW ALL THE INSTRUCTIONS
PREVIOUSLY MENTIONED, AS FAILURE
TO DO SO COULD BE DANGEROUS OR
LEAD TO THE SYSTEM WORKING
INEFFICIENTLY.

SPARES CODES

Below is a list of the codes for the

spares, available on the

website:

WUVPR – Pressure Reducing Valve 2.1 B

WUVPR3 – Pressure Reducing Valve 3.0 B

WUVPRC – Pressure Reducing Valve 1.5 B

WUVC – 22mm Check Valve

WU12EV – 12L Expansion Vessel

(Other sizes available: 8, 18, 24, 33)

WUVER – 15mm Exp. Relief Valve 3.5 B

WUVTP – 15mm P & T Relief Valve 4.5 B

WUEIH – 3kW Immersion Heater

WUTUND – 15 x 22mm Tundish

WUEDAC – Dual Thermostat

WUEMZV22 – 22mm Motorised Zone Valve

Other sizes and pressures available on our
website:

www.mcdonaldwaterstorage.com