Lochinvar CVL075075 Installation And Operating Manual Download

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100221773_2000189439_Rev. 01

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COMBO HEATING

This section serves as a guide for the installation and use
of “Combo” heating systems utilizing a domestic water
heater that has been specifically approved for such use.
It is written for those knowledgeable in the required trades
and professionals involved in the design and installation
of Combo Heating Systems.
It is the responsibility of the installer/designer to follow all
applicable codes to ensure the effectiveness and safety
of the installation.

System Requirements

The following requirements must be met for the installation
of Combo Heating Systems:
1. All components used for the distribution of water in

the heating loop must be suitable for potable water.
These include all piping, fittings, solder and fluxes,
pumps for circulation of water, valves, etc.

2. The water heater must not be connected to a hydronic

heating system that has been used previously. This
heater is not designed to be used in a space heating
only application.

3. No boiler treatment chemicals of any kind shall be

introduced into the system.

4. The Combo System components must be selected

and sized to meet and maintain the total calculated
demands  for  both  domestic  service  hot  water
and  space  heating  requirement.  The  sizing  and
installation  must  be  performed  in  accordance  with
good  engineering  practice  such  as

“ASHRAE

Handbooks”, HRAI’s Unified Combo Guidelines,
“Hydronics Institute Manuals”, ANSI Z223.1, CSA
F280, National/Provincial Building Codes

, ANSI

and/or codes having jurisdiction.

5. The air handler (fan coil) and/or the circulating pump

in a baseboard hydronic loop will require a dedicated
120V circuit. This must be provided and identified for
this purpose.

6. All piping between the water heater and the air handler

or hydronic baseboard loop must be adequately
insulated to reduce heat loss.

7. If the local jurisdiction requires a back-flow preventer

in the cold water line, an expansion tank of adequate
size must be installed.

8. “Combo” Heating Systems require higher water

temperatures than other applications. When the
system is used to supply water for Combo Heating
applications, a means, such as mixing valve, must be
installed to temper the water in order to reduce scald
hazard potential (see Figure 22 & Figure 23).

Installation

The heating mode may be one of the following options:
A. A fan coil/air handler (Figure 22).
B. A hydronic baseboard (finned tube) loop/In floor

heating (Figure 23).

The following is a list of requirements for the installation
of option A or B.

1. Install shut-off valves and unions so that the water

heater can be isolated from the heating module should
servicing of the water heater become necessary.

2. Install a drain valve at the lowest point of the heating

loop so that water can be drained from the heating
module without affecting the water heater.

3. If the air handler does not have a venting means at

the highest point of the piping arrangement, install
an air bleed at the highest point of the plumbing
arrangement.

4. Important:

Install a spring loaded check valve in

the side tap return line to prevent cold water from
continuously entering the water heater. Failure to
install such a valve could cause “stacking” and cause
the T&P valve to open.

WATER

HEATER

HOT

OUTLET

EXPANSION TANK (OPTIONAL)

MIXING

VALVE

COLD
INLET

CHECK VALVE (IF USED
REQUIRES EXPANSION TANK)

COLD SUPPLY

HOSE BIB

(OPTIONAL)