Hi Delta CHX Option

On it's own, the Hi Delta line operates at 84% thermal efficiency for boilers, and 85% for water heaters and pool heaters. By adding the external Condensing Heat Exchanger (CHX) to a Hi Delta, a great deal of additional heat is recovered from the exhaust gases, increasing the system efficiency to an unequaled 98% at full fire. Removing that much heat from the exhaust gases does affect the venting of the unit, so the vent system must be carefully designed for proper operation.

The CHX option is only available on Hi Delta units in sizes 402B-2002B.

Multiple configurations are available to fit your installation needs, low-profile or small footprint, top-mounted or rear-mounted. The CHX can be installed on racked units as well, allowing for this same high efficiency up to 4,000,000 BUH input in the space of a single unit.

Can be used indoor or outdoor; some venting components require protection in outdoor installations.

All configurations require either an extractor or a power venter to overcome the pressure drop through the CHX. Please note that Raypak does not supply extractors. Raypak-supplied power venters are from Tjernlund Products.

For ease of ordering, the CHX option is designed as a series of packages which each include the needed components for a given configuration. All packages are available for all sizes, see below.

Because the temperature of the water entering the heat exchanger has a major bearing on the system performance and flue design, please note the following design criteria:

Table 1: Hi Delta/CHX Venting Material Options

    Extractor Fan Power Venter
Maximum Inlet Water temp to CHX Applications Note 1 Note 2 Note 3 Note 4
Up to 100F Heat pump or pool Cat I, B-Vent or PVC Cat IV, PVC Cat IV, PVC Cat I, B-vent or PVC
Up to 120F Low-temp DHW Cat I, B-Vent or CPVC Cat IV, CPVC Cat IV, CPVC Cat I, B-vent or CPVC
120-140F Typical DHW Cat IV, CPVC Cat IV, CPVC    
Above 140F steady Hydronic heating Cat I, B-Vent Cat IV, AL29-4C Cat IV, AL29-4C Cat I, B-vent

Note 1 A fixed-speed roof-mounted extractor, with barometric dampers used for draft relief
Note 2 A variable-speed roof-mounted extractor. No barometric damper required.
Note 3 An inline power venter with barometric damper for draft relief.
Note 4 A wall-mounted or ceiling-mounted power vent with barometric damper for draft relief.

All of the fixed-speed systems shown can be used when you direct vent the combustion air from the outside, but openings in the wall must be provided that will provide the proper volume of excess of excess air to operate the barometric damper.

If the configurations shown do not meet our needs, contact your Raypak sales rep for further assistance.

Please note that all domestic hot water systems require two pumps -- one for the heater and one for the CHX. See table for the CHX pump. Use standard pump selection for the heater. DHW systems must also include a flow switch for the CHX. See option F-1 below.

CHX Pump for Domestic Hot Water Systems
Heater Size Pump Description
402B-902B Stainless steel with 2" flanges
992B-2002B Bronze with 2-1/2" flanges
992B-2002B Cast iron bronze-fitted (CIBF) with 2-1/2" flanges


The following CHX package designs are available:
Package # of Units Description
HDCHX1 1 Top-mounted CHX with a power venter
HDCHX2 1 Rear-mounted CHX with power venter
HDCHX3 2 Stacked rear-mounted CHXs with power venters
HDCHX4 1 Top-mounted CHX with variable-speed extractor
HDCHX5 1 Top-mounted CHX with fixed-speed extractor
HDCHX6 1 Rear-mounted CHX with variable-speed extractor
HDCHX7 1 Rear-mounted CHX with fixed-speed extractors
HDCHX8 2 Stacked rear-mounted CHXs with variable-speed extractor
HDCHX9 2 Stacked rear-mounted CHXs with fixed-speed extractors

HDCHX packages include the venting connectors, racks and vent adapters required for that particular configuration. They do not include the Hi Delta unit itself, or the CHX.

HDCHX1




Notes on HDCHX1 package:
  • This design is not approved for systems with return water temperature between 120F and 140F
  • Field-supplied transition adapter may be required.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the power venter.
  • When selecting this system, room air must be provided for both ventilation and combustion air. The power vent can be mounted either as shown or as near the ceiling as possible. All flue piping between the CHX and the power vent must be category IV. Connecting piping is not provided by Raypak.
  • See table 1 to confirm venting category of discharge piping.
  

HDCHX2




Notes on HDCHX2 package:
  • This design is not approved for systems with return water temperature between 120F and 140F
  • Rear-mounted CHX units must include the D-14 rear vent tee to change the flue outlet connection from the top port to the rear port. See Hi Delta Venting Accessories. (link)
  • Field-supplied transition adapter may be required.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the power venter.
  • When selecting this system, room air must be provided for both ventilation and combustion air. The power vent can be mounted either as shown or as near the ceiling as possible. All flue piping between the CHX and the power vent must be category IV. Connecting piping is not provided by Raypak.
  • See table 1 to confirm venting category of discharge piping.
  

HDCHX3




Notes on HDCHX3 package:
  • This design is not approved for systems with return water temperature between 120F and 140F
  • Rear-mounted CHX units must include the D-14 rear vent tee to change the flue outlet connection from the top port to the rear port. See Hi Delta Venting Accessories. (link)
  • Field-supplied transition adapter may be required.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the power venter.
  • When selecting this system, room air must be provided for both ventilation and combustion air. The power vent can be mounted either as shown or as near the ceiling as possible. All flue piping between the CHX and the power vent must be category IV. Connecting piping is not provided by Raypak.
  • Outdoor air sensor included
  • See table 1 to confirm venting category of discharge piping.
  

HDCHX4




Notes on HDCHX4 package:
  • This system is designed to be used when you direct vent the combustion air from the outside. A wall opening that communicates directly with the outdoors is required for ventilation air, in accordance with the Hi Delta I & O manual. The installation will have no outside air to operate the unit and must have a variable-speed extractor supplied by the installer. The extractor may be installed either vertically or horizontally.
  • Field-supplied transition adapter may be required.
  • When using this package on systems involving a condensing vent, confirm that the extractor selected is suitable for use on condensing vent systems.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the extractor.
  • See table 1 to confirm venting category of discharge piping.
  

HDCHX5




Notes on HDCHX5 package:
  • A fixed-speed extractor provided by the installer must be used with the barometric damper. The extractor may be installed either vertically or horizontally.
  • When using this package on systems involving a condensing vent, confirm that the extractor selected is suitable for use on condensing vent systems.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the extractor.
  • See table 1 to confirm venting category of discharge piping.
  

HDCHX6




Notes on HDCHX6 package:
  • This system is designed to be used when you direct vent the combustion air from the outside. A wall opening that communicates directly with the outdoors is required for ventilation air, in accordance with the Hi Delta I & O manual. The installation will have no outside air to operate the unit and must have a variable-speed extractor supplied by the installer. The extractor may be installed either vertically or horizontally.
  • Rear-mounted CHX units must include the D-14 rear vent tee to change the flue outlet connection from the top port to the rear port. See Hi Delta Venting Accessories. (link)
  • Field-supplied transition adapter may be required.
  • When using this package on systems involving a condensing vent, confirm that the extractor selected is suitable for use on condensing vent systems.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the extractor.
  • See table 1 to confirm venting category of discharge piping.
  

HDCHX7




Notes on HDCHX7 package:
  • A fixed-speed extractor provided by the installer must be used with the barometric damper. The extractor may be installed either vertically or horizontally.
  • Rear-mounted CHX units must include the D-14 rear vent tee to change the flue outlet connection from the top port to the rear port. See Hi Delta Venting Accessories. (link)
  • Field-supplied transition adapter may be required.
  • When using this package on systems involving a condensing vent, confirm that the extractor selected is suitable for use on condensing vent systems.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the extractor.
  • See table 1 to confirm venting category of discharge piping.
  

HDCHX8




Notes on HDCHX8 package:
  • This system is designed to be used when you direct vent the combustion air from the outside. A wall opening that communicates directly with the outdoors is required for ventilation air, in accordance with the Hi Delta I & O manual. The installation will have no outside air to operate the unit and must have a variable-speed extractor supplied by the installer. The extractor may be installed either vertically or horizontally.
  • Rear-mounted CHX units must include the D-14 rear vent tee to change the flue outlet connection from the top port to the rear port. See Hi Delta Venting Accessories. (link)
  • Field-supplied transition adapter may be required.
  • When using this package on systems involving a condensing vent, confirm that the extractor selected is suitable for use on condensing vent systems.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the extractor.
  • See table 1 to confirm venting category of discharge piping.
  

HDCHX9




Notes on HDCHX9 package:
  • A fixed-speed extractor provided by the installer must be used with the barometric damper. The extractor may be installed either vertically or horizontally.
  • Rear-mounted CHX units must include the D-14 rear vent tee to change the flue outlet connection from the top port to the rear port. See Hi Delta Venting Accessories. (link)
  • Field-supplied transition adapter may be required.
  • When using this package on systems involving a condensing vent, confirm that the extractor selected is suitable for use on condensing vent systems.
  • A lockable balancing baffle or blast baffle may be required to control excess draft. This must be located between the barometric damper and the extractor.
  • See table 1 to confirm venting category of discharge piping.
  

Options Related to the CHX Design

D-2 Power Venter, Fixed-Speed

Opens to relieve excess pressure in the heat exchanger if the pressure exceeds 75 PSIG.
  • Shipped loose.
  

D-12 Barometric Damper, Single-Acting

  • See Hi Delta Venting options (link)
  • Shipped loose for field mounting on outlet in sizes 2002B-2342B. Fittings not provided.
  

D-15 Sidewall Vent Termination Cap

  • See Hi Delta Venting options (link)
  

D-18 Adapter, Barometric Damper

  • See Hi Delta Venting options (link)
  

D-19 Adapter, Flue Termination Cap

  • See Hi Delta Venting options (link)
  

D-24 Elbow, Flue Exhaust

Fits between the flue collar on the unit and the intake of the CHX. Used only on installations with a top-mounted CHX. Adapters required on both ends (options D-27 and D-28).
  • Shipped loose.
  

D-26 Tee, Barometric Damper

Provides a connecting point for the D-12 barometric damper for those systems where draft relief is required .
  • Shipped loose.
  

D-27 Adapter, Male

Connects between the D-24 elbow and the CHX intake port
  • Shipped loose.
  

D-28 Adapter, Female

Connects between the D-24 elbow and the Hi Delta top vent port
  • Shipped loose.
  

D-29 Extender, Flue Exhaust

Used only on the lower unit in a stacked configuration. This extends the flue pipe between the Hi Delta rear vent port, required due to the stacked CHX configuration.
  • Shipped loose.
  

F-1 Flow Switch

Required for the CHX in a domestic hot water installation.
  • Shipped loose.
  

X-5 Rack Kit for Top-Mounted CHX

This rack holds the CHX in position. Two different designs are used: one for single top-mounted systems, and one for the upper unit in a stacked pair. For a single rear-mounted unit, or the lower unit in a stacked pair, use option X-6.
  • Shipped loose, unassembled.
  

X-6 Base/Rack Kit for Rear-Mounted CHX

This rack holds the CHX in the proper position for a rear-mounted design. For a single to-mouinted unit, or the upper unit in a stacked pair, use option X-5.
  • Shipped loose, unassembled.
  

Z-11 Silicone, 10 oz Tube

Required for vent connections.
  • Shipped loose.